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Asrani SG, McGlumphy EJ, Al-Aswad LA, Chaya CJ, Lin S, Musch DC, Pitha I, Robin AL, Wirostko B, Johnson TV. The relationship between intraocular pressure and glaucoma: an evolving concept. Prog Retin Eye Res 2024:101303. [PMID: 39303763 DOI: 10.1016/j.preteyeres.2024.101303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 09/17/2024] [Accepted: 09/18/2024] [Indexed: 09/22/2024]
Abstract
Intraocular pressure (IOP) is the most important modifiable risk factor for glaucoma and fluctuates considerably within patients over short and long time periods. Our field's understanding of IOP has evolved considerably in recent years, driven by tonometric technologies with increasing accuracy, reproducibility, and temporal resolution that have refined our knowledge regarding the relationship between IOP and glaucoma risk and pathogenesis. The goal of this article is to review the published literature pertinent to the following points: 1) the factors that determine IOP in physiologic and pathologic states; 2) technologies for measuring IOP; 3) scientific and clinical rationale for measuring diverse IOP metrics in patients with glaucoma; 4) the impact and shortcomings of current standard-of-care IOP monitoring approaches; 5) recommendations for approaches to IOP monitoring that could improve patient outcomes; and 6) research questions that must be answered to improve our understanding of how IOP contributes to disease progression. Retrospective and prospective data, including that from landmark clinical trials, document greater IOP fluctuations in glaucomatous than healthy eyes, tendencies for maximal daily IOP to occur outside of office hours, and, in addition to mean and maximal IOP, an association between IOP fluctuation and glaucoma progression that is independent of mean in-office IOP. Ambulatory IOP monitoring, measuring IOP outside of office hours and at different times of day and night, provides clinicians with discrete data that could improve patient outcomes. Eye care clinicians treating glaucoma based on isolated in-office IOP measurements may make treatment decisions without fully capturing the entire IOP profile of an individual. Data linking home blood pressure monitors and home glucose sensors to dramatically improved outcomes for patients with systemic hypertension and diabetes and will be reviewed as they pertain to the question of whether ambulatory tonometry is positioned to do the same for glaucoma management. Prospective randomized controlled studies are warranted to determine whether remote tonometry-based glaucoma management might reduce vision loss and improve patient outcomes.
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Affiliation(s)
- Sanjay G Asrani
- Department of Ophthalmology, Duke University Medical Center, Durham, NC, USA
| | | | - Lama A Al-Aswad
- Scheie Eye Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Craig J Chaya
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Shan Lin
- Glaucoma Center of San Francisco, San Francisco, CA, USA
| | - David C Musch
- Department of Ophthalmology & Visual Sciences and Department of Epidemiology, Kellogg Eye Center, University of Michigan, Ann Arbor, MI, USA
| | - Ian Pitha
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Alan L Robin
- Department of Ophthalmology & Visual Sciences and Department of Epidemiology, Kellogg Eye Center, University of Michigan, Ann Arbor, MI, USA; Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Barbara Wirostko
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA.
| | - Thomas V Johnson
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Muhsinoglu O, Akalin I, Karadag R, Yilmaz S, Bayramlar H, Nicholson JD. Heterozygous Pyrin (MEFV) E148Q allele carriers indicate a reduced glaucoma risk for Turkish population: a prospective clinical analysis. Ophthalmic Genet 2024; 45:332-336. [PMID: 38482581 DOI: 10.1080/13816810.2024.2324362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 02/12/2024] [Accepted: 02/23/2024] [Indexed: 09/11/2024]
Abstract
PURPOSE The MEFV gene encodes pyrin, a protein linked to increased severity of symptoms in Familial Mediterranean Fever (FMF). We consider that inflammation due to MEFV variants would increase eye inflammation and damage aqueous humor regulation. The present study is the first analysis investigating a MEFV (E148Q) variant as a marker protecting from glaucoma. METHODS In this prospective clinical analyze, we performed detailed gene sequencing focusing on 22 specific regions of the pyrin (MEFV) gene. The study involved two distinct groups: individuals diagnosed with glaucoma (n = 200) and control subjects without glaucoma (n = 100). Both groups were carefully selected to exclude individuals with symptoms or a previous diagnosis of Familial Mediterranean Fever (FMF). The diagnosis of glaucoma for each participant was rigorously established through comprehensive direct ophthalmic examinations. RESULTS A significant odds ratio for protection against glaucoma was found in carriers of the subclinical E148Q allele (OR:2.22; 95%CI: 1.098-4.485). No significant differences were found for other variants. One mutant E148Q-allele could decrease the probability of glaucoma development by approximately 68,9%. We observed no differences in the genotype frequency between glaucoma and healthy for the other MEFV gene variants. CONCLUSION The pyrin variant of the MEFV gene resulting in a subclinical phenotype appears to reduce the incidence of glaucoma, and heterozygous pyrin (MEFV) E148Q allele carriers confer protection against glaucoma. It is important to consider the limitations arising from the relatively small number of studies conducted on this topic.
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Affiliation(s)
- Orkun Muhsinoglu
- Faculty of Medicine, Ophthalmology, Maltepe University, Istanbul, Turkey
| | - Ibrahim Akalin
- Faculty of Medicine, Medical Genetics, Maltepe University, Istanbul, Turkey
| | - Remzi Karadag
- Ophthalmology, Veni Vidi Eye Hospital, Istanbul, Turkey
| | - Sarenur Yilmaz
- Faculty of Medicine, Medical Genetics, Medeniyet University, Istanbul, Turkey
| | | | - James D Nicholson
- Department of Neurology, The University of Maryland Baltimore, New York, USA
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Masdipa A, Kaidzu S, Tanito M. Assessing the Impact of PRESERFLO MicroShunt on Intraocular Pressure in Porcine Eyes Ex Vivo Using Infusion Pump System. Bioengineering (Basel) 2024; 11:669. [PMID: 39061751 PMCID: PMC11274192 DOI: 10.3390/bioengineering11070669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/05/2024] [Accepted: 06/28/2024] [Indexed: 07/28/2024] Open
Abstract
To evaluate the effectiveness of the PRESERFLO MicroShunt (PFM) in reducing intraocular pressure (IOP) ex vivo in porcine eyes using an infusion pump system and to simulate various IOP conditions, In this study, porcine eyes received increasing flows between 2 and 20 μL/min. IOP measurements were taken under conditions with and without the PFM [PFM (+) and PFM (-), respectively]. In the PFM (-) group, IOP increased from 7.4 mmHg to 46.3 mmHg as the flow rate increased from 2 μL/min to 20 μL/min. The rate of IOP reduction (%ΔIOP) rose with increasing flow rates, although the absolute IOP values achieved with the PFM insertion also increased. The correlation between IOPs in the PFM (-) conditions and the %ΔIOP was modeled as %ΔIOP = 22.4 Ln [PFM(-) IOP] - 41.7. According to this equation, IOP reduction by PFM insertion is 0% at IOPs of 6.4 mmHg or lower. IOP reductions of 10%, 20%, 30%, and 40% were observed when the pre-insertion IOPs were 10.1, 15.7, 24.6, and 38.4 mmHg, respectively. Achievable post-insertion IOP levels of ≤21 mmHg, ≤18 mmHg, ≤15 mmHg, and ≤12 mmHg corresponded to the initial IOPs of 33 mmHg, 26 mmHg, 20 mmHg, and 14.8 mmHg, respectively. In conclusion, the PFM effectively reduced IOP within a specific range of IOP values in an ex vivo experimental system. In clinical situations, the PFM is unlikely to be effective at low IOP levels. At higher levels, the PFM reduces IOP, but it may be insufficient to achieve the target IOP.
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Affiliation(s)
| | | | - Masaki Tanito
- Department of Ophthalmology, Shimane University Faculty of Medicine, Izumo 693-8501, Japan; (A.M.); (S.K.)
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Fard MRB, Chan J, Read AT, Li G, Cheng L, Safa BN, Siadat SM, Jhunjhunwala A, Grossniklaus HE, Emelianov SY, Stamer WD, Kuehn MH, Ethier CR. Magnetically Steered Cell Therapy For Functional Restoration Of Intraocular Pressure Control In Open-Angle Glaucoma. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.13.593917. [PMID: 38798683 PMCID: PMC11118342 DOI: 10.1101/2024.05.13.593917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Trabecular meshwork (TM) cell therapy has been proposed as a next-generation treatment for elevated intraocular pressure (IOP) in glaucoma, the most common cause of irreversible blindness. Using a magnetic cell steering technique with excellent efficiency and tissue-specific targeting, we delivered two types of cells into a mouse model of glaucoma: either human adipose-derived mesenchymal stem cells (hAMSCs) or induced pluripotent cell derivatives (iPSC-TM cells). We observed a 4.5 [3.1, 6.0] mmHg or 27% reduction in intraocular pressure (IOP) for nine months after a single dose of only 1500 magnetically-steered hAMSCs, associated with restoration of function to the conventional outflow pathway, as judged by increased outflow facility and TM cellularity. iPSC-TM cells were also effective, but less so, showing only a 1.9 [0.4, 3.3] mmHg or 13% IOP reduction and increased risk of tumorigenicity. In both cases, injected cells remained detectable in the iridocorneal angle three weeks post-transplantation. Based on the locations of the delivered cells, the mechanism of IOP lowering is most likely paracrine signaling. We conclude that magnetically-steered hAMSC cell therapy has potential for long-term treatment of ocular hypertension in glaucoma. One Sentence Summary A novel magnetic cell therapy provided effective intraocular pressure control in a mouse model of glaucoma, motivating future translational studies.
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Xu FY, Lam AK. Intraocular pressure variation from ocular compression in low and high myopia. Clin Exp Optom 2024; 107:213-218. [PMID: 36975202 DOI: 10.1080/08164622.2023.2191784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 03/10/2023] [Indexed: 03/29/2023] Open
Abstract
CLINICAL RELEVANCE Change in intraocular pressure during acute ocular compression is related to aqueous humour dynamics. Monitoring intraocular pressure (IOP) change throughout ocular compression has potential to evaluate aqueous outflow facilities. BACKGROUND Recent studies have monitored lamina cribrosa deformation using optical coherence tomography during ocular compression. IOP was measured only once immediately after ocular compression. This study aimed to evaluate IOP changes during and after ocular compression and compare the differences between low and high myopia. METHODS Two groups of young, healthy adults were age-matched and underwent ocular compression. IOP was measured at baseline and monitored during a 2-min ocular compression followed by a 10-min recovery phase. Rebound tonometry was used and applied at 30-s intervals. RESULTS Thirty low and 30 high myopes (60 right eyes) were included in the study. They had similar baseline IOP at 14.9 mmHg. IOP was elevated to 21.7 ± 3.8 mmHg and 22.3 ± 4.2 mmHg for the low and high myopic group, respectively (p = 0.877). Low myopes had faster IOP decay during ocular compression at -3.24 mmHg/min than high myopes at -2.58 mmHg/min (p = 0.0528). The IOP dropped below the baseline level after the release of the compressive force. Low myopes had IOP that returned to baseline levels faster (at 360 s) than high myopes (at 510 s). CONCLUSION Measuring IOP once immediately after ocular compression could under-estimate the effect of IOP elevation during ocular compression. Further studies are required regarding IOP changes from ocular compression in aqueous humour dynamics.
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Affiliation(s)
- Fang-Yu Xu
- School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong
| | - Andrew Kc Lam
- School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong
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Lyons LJ, Kazemi A, Bakri SJ, Barkmeier AJ, Iezzi R, Olsen TW, Hodge DO, Sit AJ. The Effect of Scleral Buckle Surgery on Tonographic Outflow Facility, Positional Intraocular Pressure, and Ocular Biomechanics. Ophthalmol Glaucoma 2024; 7:1-7. [PMID: 37482122 DOI: 10.1016/j.ogla.2023.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/15/2023] [Accepted: 07/17/2023] [Indexed: 07/25/2023]
Abstract
PURPOSE To investigate the in vivo effect of scleral buckle surgery on ocular biomechanics and aqueous humor dynamics. DESIGN Prospective observational cross-sectional study. PARTICIPANTS Nine patients with unilateral 360 degree encircling scleral buckles without vitrectomy for rhegmatogenous retinal detachments, between 3 and 39 months postoperative. METHODS All measurements were performed in both eyes of all participants. Intraocular pressure (IOP) was measured in the seated and supine positions using pneumatonometry. Outflow facility was measured using 2-minute weighted pneumatonography. Ocular rigidity coefficient was determined from the Friedenwald equations based on the difference in IOP with and without a weighted tonometer tip. The percentage change in IOP upon transitioning from seated to supine was calculated. Measurements for buckled and nonbuckled eyes were compared using paired Student t test of means. MAIN OUTCOME MEASURES Sitting and supine IOP and percentage difference between the 2 positions; outflow facility; ocular rigidity coefficient. RESULTS Seated IOP was similar between buckled and nonbuckled eyes (16.1 ± 2.5 vs. 16.7 ± 2.7 mmHg; P = 0.5) whereas supine IOP was lower in buckled eyes compared with nonbuckled eyes (18.7 ± 2.6 vs. 21.3 ± 2.5 mmHg; P = 0.008). The percentage increase in IOP upon change in body position from seated to supine was greater in nonbuckled eyes (17.4 ± 9.4% vs. 27.6 ± 9.5%; P = 0.005). Ocular rigidity coefficient was lower in buckled (9.9 × 10-3 ± 1.4 × 10-3 μL-1) vs. nonbuckled eyes (14.4 × 10-3 ± 3.1 × 10-3 μL-1; P = 0.006). Outflow facility was not significantly different in buckled and nonbuckled eyes. CONCLUSIONS Scleral buckling decreases ocular rigidity but does not affect outflow facility. This change in ocular biomechanics likely results in the attenuated IOP change from seated to supine position. Decreased ocular rigidity may also reduce IOP fluctuations and potentially reduce the risk for glaucoma progression. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Lance J Lyons
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota
| | - Arash Kazemi
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota
| | - Sophie J Bakri
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota
| | | | - Raymond Iezzi
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota
| | - Timothy W Olsen
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota
| | - David O Hodge
- Department of Quantitative Health Sciences, Mayo Clinic, Jacksonville, Florida
| | - Arthur J Sit
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota.
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Mimura M, Akagi T, Kohmoto R, Fujita Y, Sato Y, Ikeda T. Measurement of vitreous humor pressure in vivo using an optic fiber pressure sensor. Sci Rep 2023; 13:18233. [PMID: 37880357 PMCID: PMC10600124 DOI: 10.1038/s41598-023-45616-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 10/21/2023] [Indexed: 10/27/2023] Open
Abstract
We conducted a study to assess the pressure difference between the aqueous and vitreous humors in rabbit eyes using a direct intraocular pressure (IOP) measurement method. A micro-optic-fiber pressure sensor was utilized for this purpose. Preliminary experiments with enucleated porcine eyes confirmed the sensor's accuracy in measuring both aqueous and vitreous humor pressure. The main study involved six healthy albino rabbits, where the sensor measured the pressure in the anterior chamber (aIOP) and posterior vitreous-cavity (pIOP). These measurements were compared to aIOP values obtained through rebound tonometry. Additionally, pre- and postoperative pressure comparisons were made after performing a vitrectomy. Results revealed a significant disparity between aqueous and vitreous humor pressures. Prior to vitrectomy, pIOP was 22.8 mmHg, over twice as high as aIOP (11.0 mmHg), but decreased to a similar level following the procedure. Comparison between the sensor measurements and rebound tonometry showed agreement in aIOP values. In conclusion, our study demonstrates that vitreous humor pressure is consistently higher than aqueous humor pressure, reaching the upper limit of normal IOP. Furthermore, vitrectomy effectively reduces pIOP, aligning it with aIOP. These findings contribute valuable insights into intraocular pressure dynamics and have implications for clinical interventions targeting ocular pressure regulation.
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Affiliation(s)
- Masashi Mimura
- Department of Ophthalmology, Osaka Medical College, Takatsuki-City, Osaka, Japan.
- Department of Ophthalmology, Hyogo Medical University, 1-1, Mukogawa-Cho, Nishinomiya-Shi, Hyogo , 663-8501, Japan.
- Department of Ophthalmology, Toho University Sakura Medical Center, Sakura-City, Chiba, Japan.
| | - Tadamichi Akagi
- Division of Ophthalmology and Visual Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Ryosuke Kohmoto
- Department of Ophthalmology, Osaka Medical College, Takatsuki-City, Osaka, Japan
| | - Yasushi Fujita
- Department of Ophthalmology, Osaka Medical College, Takatsuki-City, Osaka, Japan
| | - Yohei Sato
- Department of Ophthalmology, Osaka Medical College, Takatsuki-City, Osaka, Japan
| | - Tsunehiko Ikeda
- Department of Ophthalmology, Osaka Medical College, Takatsuki-City, Osaka, Japan
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Kaufman AR, Elhusseiny AM, Edward DP, Vajaranant TS, Aref AA, Abbasian J. Topical netarsudil for treatment of glaucoma with elevated episcleral venous pressure: A pilot investigation in sturge-weber syndrome. Eur J Ophthalmol 2023; 33:1969-1976. [PMID: 36850063 DOI: 10.1177/11206721231159694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
PURPOSE Topical netarsudil 0.02% may reduce intraocular pressure (IOP) by decreasing episcleral venous pressure (EVP), which carries theoretical utility for glaucoma associated with elevated EVP. A role for netarsudil in patients with elevated EVP is evaluated in a pilot investigation using a cohort of individuals with Sturge-Weber syndrome (SWS). METHODS Retrospective study of patients with SWS and glaucoma who were treated with netarsudil. Five patients (six eyes) were identified. Data collected included demographics, visual acuity, IOP, glaucoma medical and surgical treatments, and adverse effects of netarsudil. RESULTS Mean age was 13.6 ± 8.5 years. EVP elevation was presumed based on clinical stigmata and/or historical features. Mean number of baseline glaucoma medications was 3.3 ± 1.2. There was a significant reduction in the IOP at netarsudil initiation (mean 26.2 ± 4.5 mmHg) to 1 month of netarsudil therapy (mean 20.2 ± 3.8 mmHg, p = 0.0283) and latest IOP on netarsudil (mean 17.6 ± 1.4 mmHg, p = 0.0034). Mean duration of netarsudil therapy was 18.7 ± 11.8 months. Three patients required additional glaucoma procedures; one patient required an additional glaucoma medication. Three eyes (50%) developed conjunctival hyperemia. One patient discontinued netarsudil at 29 months, to reduce drop burden. CONCLUSIONS Netarsudil can effectively reduce IOP in patients with SWS, even when used as a fourth or fifth glaucoma medication. A possible role for netarsudil in the management of patients with elevated EVP is suggested pending further future investigations.
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Affiliation(s)
- Aaron R Kaufman
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, University of Illinois at Chicago, Chicago, IL, USA
| | - Abdelrahman M Elhusseiny
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, University of Illinois at Chicago, Chicago, IL, USA
- Department of Ophthalmology, Harvey and Bernice Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Deepak P Edward
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, University of Illinois at Chicago, Chicago, IL, USA
| | - Thasarat Sutabutr Vajaranant
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, University of Illinois at Chicago, Chicago, IL, USA
| | - Ahmad A Aref
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, University of Illinois at Chicago, Chicago, IL, USA
| | - Javaneh Abbasian
- Department of Ophthalmology and Visual Sciences, Illinois Eye and Ear Infirmary, University of Illinois at Chicago, Chicago, IL, USA
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Baumgarten S, Plange N, Htoon HM, Lohmann T, Videa A, Koutsonas A, Schellhase H, Kuerten D, Walter P, Fuest M. Outcomes of combined single-use dual blade goniotomy and cataract surgery. Int Ophthalmol 2022; 42:2685-2696. [PMID: 35357642 PMCID: PMC9420088 DOI: 10.1007/s10792-022-02257-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 03/12/2022] [Indexed: 11/26/2022]
Abstract
Purpose Single-use dual blade goniotomy (SBG) is a novel ab interno procedure that removes three to five clock hours of trabecular meshwork (TM). We analysed the reduction of intraocular pressure (IOP) and topical glaucoma medication (Meds) in eyes following combined cataract surgery and SBG (Cat-SBG).
Methods IOP and Meds were evaluated retrospectively in 55 eyes of 38 patients. 44 eyes had high tension glaucoma (HTG) and eleven eyes had normal tension glaucoma (NTG). Complete success (no Meds) and qualified success (with Meds) for IOP levels ≤ 21, ≤ 18 , ≤ 16 mmHg or ≥ 20% IOP reduction at the two- and six-month follow-up were evaluated.
Results IOP and Meds were significantly reduced from before to two months after Cat-SBG in HTG- and NTG-patients (HTG: IOP 19.4 ± 3.3 to 15.1 ± 3.3 mmHg; p < 0.001; Meds 2.1 ± 1.3 to 0.8 ± 1.3; p < 0.001; NTG: IOP 14.0 ± 2.3 to 11.5 ± 2.3 mmHg; p = 0.004; Meds 1.6 ± 0.7 to 0.3 ± 0.7; p < 0.001). IOP and Meds did not change significantly from two to six months after Cat-SBG. In HTG, complete and qualified success rates were 43% (19/44) and 93% (41/44) for IOP ≤ 18 mmHg, 36% (16/44) and 64% (28/44) for IOP ≤ 16 mmHg and 30% (13/44) and 43% (19/44) for ≥ 20% IOP reduction six months after surgery. In NTG, complete and qualified success was 81% (9/11) and 100% (11/11) for IOP ≤ 18 and ≤ 16 mmHg, and 27% (3/11) for IOP reduction ≥ 20%. IOP and Meds reduction were comparable between HTG and NTG eyes. Only minor postoperative complications occurred. Conclusion Cat-SBG is an efficient method to significantly lower IOP in patients with HTG and NTG.
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Affiliation(s)
- Sabine Baumgarten
- Department of Ophthalmology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany.
| | - Niklas Plange
- Augenzentrum Am Annapark, Steigerweg 3, 52477, Alsdorf, Germany
| | - Hla Myint Htoon
- Singapore Eye Research Institute, 11 Third Hospital Ave, Singapore City, 168751, Singapore.,Duke-NUS Medical School, 8 College Road, Singapore City, 169857, Singapore
| | - Tibor Lohmann
- Department of Ophthalmology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Andreas Videa
- Department of Ophthalmology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Antonis Koutsonas
- Department of Ophthalmology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Hannah Schellhase
- Department of Ophthalmology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - David Kuerten
- Department of Ophthalmology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Peter Walter
- Department of Ophthalmology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Matthias Fuest
- Department of Ophthalmology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany.
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10
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Casson RJ. Medical therapy for glaucoma: A review. Clin Exp Ophthalmol 2022; 50:198-212. [PMID: 35037367 DOI: 10.1111/ceo.13989] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/17/2021] [Accepted: 08/23/2021] [Indexed: 12/12/2022]
Abstract
A number of pharmacological targets are exploited to modify the parameters in the Goldmann equation and reduce the intraocular pressure (IOP). This strategy constitutes the foundation for the medical management of glaucoma, the evolution of which, until only recently, has been in relative stagnation. A burst of innovation has produced new ocular hypotensive drugs and long-acting delivery methods, including intracameral delivery, which are expanding the clinician's medical armamentarium. A number of IOP-independent neuroprotection strategies have shown strong potential in animal models of glaucoma, but translational attempts have been surprisingly limited. However, while pharmacological options are expanding, the traditional role of topical medical therapy is being challenged by selective laser trabeculoplasty, micro-invasive glaucoma surgery, and sustained delivery methods. A scientifically rigorous assessment of new treatments will be critical to empower clinicians with evidence-based information to optimise vision preservation and quality of life outcomes for their patients.
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Affiliation(s)
- Robert J Casson
- Ophthalmic Research Laboratories, Adelaide Health & Medical Science Building, University of Adelaide, Adelaide, Australia.,Department of Ophthalmology, Royal Adelaide Hospital, Adelaide, Australia
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11
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Kim Y, Yang J, Kim JY, Lee JM, Son WC, Moon BG. HL3501, a Novel Selective A3 Adenosine Receptor Antagonist, Lowers Intraocular Pressure (IOP) in Animal Glaucoma Models. Transl Vis Sci Technol 2022; 11:30. [PMID: 35191964 PMCID: PMC8883152 DOI: 10.1167/tvst.11.2.30] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The A3 adenosine receptor (A3AR) is a known therapeutic target for glaucoma treatment. In this study, we developed HL3501 and examined its selectivity profile and in vitro and in vivo effects. Methods For the rabbit model, intraocular pressure (IOP) was increased by laser photocoagulation of the trabecular meshwork (TM). The rabbits were then topically treated with HL3501, latanoprost, timolol, or vehicle for 3 weeks. For the mouse model, HL3501, latanoprost, or vehicle was administered following induced IOP elevation by dexamethasone (Dex). The IOP of all rabbits and mice was measured. Electroretinography was performed on both eyes of dark-adapted anesthetized mice on days 0 and 21. The mice's eyes were enucleated at the end of the treatment for immunofluorescence staining. Results HL3501 was highly specific to the A3AR and inhibitory of A3AR function. In the rabbit glaucoma model, HL3501 and latanoprost significantly decreased the IOP. In the Dex-treated mouse model, HL3501 and latanoprost significantly decreased the IOP and increased the b-wave amplitude as compared with the vehicle treatment. HL3501 and latanoprost also inhibited fibronectin and α-smooth muscle actin expression induced by Dex treatment. Conclusions HL3501 had effects similar to those of latanoprost in reducing ocular hypertension in animal models. HL3501 could be used as a novel approach to treat glaucoma. Translational Relevance HL3501 is a novel preclinical compound targeting the A3 adenosine receptor, which may also be a new treatment option to fill the unmet needs of many glaucoma patients.
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Affiliation(s)
- Yunhee Kim
- Handok Pharmaceuticals, Seoul, Republic of Korea.,Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Jaewook Yang
- T2B Infrastructure Center for Ocular Disease, Busan Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
| | - Jee Young Kim
- T2B Infrastructure Center for Ocular Disease, Busan Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea
| | - Jang Mi Lee
- Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - Woo Chan Son
- Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea
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12
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Khan S, Kirubarajan A, Lee M, Pitha I, Buckey JC. The Correlation Between Body Weight and Intraocular Pressure. Aerosp Med Hum Perform 2021; 92:886-897. [PMID: 34819215 DOI: 10.3357/amhp.5769.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
INTRODUCTION: Preflight body weight is a strong predictor of visual changes in spaceflight. To understand the effect of body weight on the eye, we examined the effect of increased body mass index on intraocular pressure on Earth.METHODS: We conducted a systematic review to summarize the relationship between weight parameters (including body mass index (BMI) and obesity indices), and intraocular pressure (IOP). Study selection and data extraction were performed in duplicate using EMBASE, MEDLINE, and CENTRAL, from database inception to the second week of April 2020.RESULTS: A total of 66 individual studies were included for qualitative analysis from the 1364 studies eligible for title and abstract screening. A total of 39 studies were available for quantitative analysis. The average BMI was 25.9 (range, 20.148.8) and the average IOP was 14.9 mmHg (range, 11.627.8). The overall pooled RR between BMI and elevated intraocular pressure (IOP) was 1.06 (95 CI%, 1.041.07), meaning for each unit increase in BMI one is 6 more likely of having higher IOP than baseline. Two studies assessed the effects of bariatric surgery, and both showed significant decreases in IOP postoperatively.CONCLUSION: A higher BMI was associated with increased IOP in ground-based studies. IOP also decreased with weight loss. These data support the idea that alterations in body weight affect intraocular pressures. Further research is needed to understand the relationship between body weight, IOP, and microgravity-induced visual changes. This finding may also be useful clinically.Khan S, Kirubarajan A, Lee M, Pitha I, Buckey JC Jr. The correlation between body weight and intraocular pressure. Aerosp Med Hum Perform. 2021; 92(11):886-897.
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13
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Greenwald SH, Macias BR, Lee SMC, Marshall-Goebel K, Ebert DJ, Liu JHK, Ploutz-Snyder RJ, Alferova IV, Dulchavsky SA, Hargens AR, Stenger MB, Laurie SS. Intraocular pressure and choroidal thickness respond differently to lower body negative pressure during spaceflight. J Appl Physiol (1985) 2021; 131:613-620. [PMID: 34166098 DOI: 10.1152/japplphysiol.01040.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Spaceflight-associated neuro-ocular syndrome (SANS) develops during long-duration (>1 mo) spaceflight presumably because of chronic exposure to a headward fluid shift that occurs in weightlessness. We aimed to determine whether reversing this headward fluid shift with acute application of lower body negative pressure (LBNP) can influence outcome measures at the eye. Intraocular pressure (IOP) and subfoveal choroidal thickness were therefore evaluated by tonometry and optical coherence tomography (OCT), respectively, in 14 International Space Station crewmembers before flight in the seated, supine, and 15° head-down tilt (HDT) postures and during spaceflight, without and with application of 25 mmHg LBNP. IOP in the preflight seated posture was 14.4 mmHg (95% CI, 13.5-15.2 mmHg), and spaceflight elevated this value by 1.3 mmHg (95% CI, 0.7-1.8 mmHg, P < 0.001). Acute exposure to LBNP during spaceflight reduced IOP to 14.2 mmHg (95% CI, 13.4-15.0 mmHg), which was equivalent to that of the seated posture (P > 0.99), indicating that venous fluid redistribution by LBNP can influence ocular outcome variables during spaceflight. Choroidal thickness during spaceflight (374 µm, 95% CI, 325-423 µm) increased by 35 µm (95% CI, 25-45 µm, P < 0.001), compared with the preflight seated posture (339 µm, 95% CI, 289-388 µm). Acute use of LBNP during spaceflight did not affect choroidal thickness (381 µm, 95% CI, 331-430 µm, P = 0.99). The finding that transmission of reduced venous pressure by LBNP did not decrease choroidal thickness suggests that engorgement of this tissue during spaceflight may reflect changes that are secondary to the chronic cerebral venous congestion associated with spaceflight.NEW & NOTEWORTHY Spaceflight induces a chronic headward fluid shift that is believed to underlie ocular changes observed in astronauts. The present study demonstrates, for the first time, that reversing this headward fluid shift via application of lower body negative pressure (LBNP) during spaceflight may alter the ocular venous system, as evidenced by a decrease in intraocular pressure. This finding indicates that LBNP has the potential to be an effective countermeasure against the headward fluid shift during spaceflight, which may then be beneficial in preventing or reversing associated ocular changes.
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Affiliation(s)
| | - Brandon R Macias
- National Aeronautics and Space Administration, Johnson Space Center, Houston, Texas
| | | | | | | | - John H K Liu
- Shiley Eye Institute, University of California, San Diego, California
| | - Robert J Ploutz-Snyder
- Applied Biostatistics Laboratory, School of Nursing, University of Michigan, Ann Arbor, Michigan
| | - Irina V Alferova
- Russian Federation State Research Center Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | | | - Alan R Hargens
- Altman Clinical and Translational Research Institute, University of California, San Diego, California
| | - Michael B Stenger
- National Aeronautics and Space Administration, Johnson Space Center, Houston, Texas
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14
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Sit AJ, Gupta D, Kazemi A, McKee H, Challa P, Liu KC, Lopez J, Kopczynski C, Heah T. Netarsudil Improves Trabecular Outflow Facility in Patients with Primary Open Angle Glaucoma or Ocular Hypertension: A Phase 2 Study. Am J Ophthalmol 2021; 226:262-269. [PMID: 33524367 DOI: 10.1016/j.ajo.2021.01.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 01/04/2023]
Abstract
PURPOSE Intraocular pressure (IOP) reduction is key to controlling primary open angle glaucoma (POAG). Pharmacotherapies for POAG or ocular hypertension (OHT) commonly lower IOP by increasing uveoscleral outflow or decreasing aqueous humor production. Netarsudil (Rhopressa), a Rho kinase inhibitor, reduces IOP by improving trabecular outflow facility, which is reduced in POAG. We investigated the effects of netarsudil on aqueous humor dynamics in patients with POAG or OHT. DESIGN Double-masked, randomized, vehicle-controlled, Phase 2 trial. METHODS Netarsudil 0.02% was instilled in 1 eye and vehicle into the contralateral eye of 20 patients once daily in the morning for 7 days. The primary endpoint was change in mean diurnal outflow facility on day 8 versus that on day 1 (baseline). Outflow facility was measured by using Schiøtz tonography, IOP by pneumotonometry, and episcleral venous pressure (EVP) by automated venomanometry. RESULTS Eighteen patients (90%) completed the study. Mean diurnal outflow facility increased 0.039 versus 0.007 µL/min/mm Hg from baseline in the netarsudil- and the vehicle-treated groups, respectively (P < .001 vs. baseline for netarsudil), a treatment difference of 0.03 µL/min/mm Hg (P ≤ .001). Mean diurnal IOP change from baseline at day 8 was -4.52 mm Hg for netarsudil versus -0.98 mm Hg for vehicle, a treatment difference of -3.54 mm Hg (P < .0001). Mean diurnal EVP change from baseline was -0.79 mm Hg in the netarsudil-treated group versus 0.10 mm Hg for vehicle, a treatment difference of -0.89 mm Hg (P < .001). All patients reporting an adverse event reported conjunctival hyperemia of mild or moderate severity. CONCLUSIONS Netarsudil acts on the conventional outflow pathway, both proximal and distal, to significantly reduce IOP in POAG and OHT by improving trabecular outflow facility and decreasing EVP.
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Affiliation(s)
- Arthur J Sit
- From the Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, USA.
| | - Divakar Gupta
- Department of Ophthalmology, Duke University, Durham, North Carolina, USA
| | - Arash Kazemi
- From the Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, USA
| | - Hayley McKee
- Aerie Pharmaceuticals, Inc., Durham, North Carolina, USA
| | - Pratap Challa
- Department of Ophthalmology, Duke University, Durham, North Carolina, USA
| | - Katy C Liu
- Department of Ophthalmology, Duke University, Durham, North Carolina, USA
| | - Jae Lopez
- Aerie Pharmaceuticals, Inc., Durham, North Carolina, USA
| | | | - Theresa Heah
- Aerie Pharmaceuticals, Inc., Durham, North Carolina, USA
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15
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Toris CB, Gagrani M, Ghate D. Current methods and new approaches to assess aqueous humor dynamics. EXPERT REVIEW OF OPHTHALMOLOGY 2021. [DOI: 10.1080/17469899.2021.1902308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Carol B. Toris
- Dept. Of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE, USA
- Dept. Of Ophthalmology and Visual Science, Case Western Reserve University, Cleveland, OH USA
| | - Meghal Gagrani
- Dept. Of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE, USA
| | - Deepta Ghate
- Dept. Of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE, USA
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16
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Li G, Lee C, Read AT, Wang K, Ha J, Kuhn M, Navarro I, Cui J, Young K, Gorijavolu R, Sulchek T, Kopczynski C, Farsiu S, Samples J, Challa P, Ethier CR, Stamer WD. Anti-fibrotic activity of a rho-kinase inhibitor restores outflow function and intraocular pressure homeostasis. eLife 2021; 10:60831. [PMID: 33783352 PMCID: PMC8009676 DOI: 10.7554/elife.60831] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 03/12/2021] [Indexed: 12/22/2022] Open
Abstract
Glucocorticoids are widely used as an ophthalmic medication. A common, sight-threatening adverse event of glucocorticoid usage is ocular hypertension, caused by dysfunction of the conventional outflow pathway. We report that netarsudil, a rho-kinase inhibitor, decreased glucocorticoid-induced ocular hypertension in patients whose intraocular pressures were poorly controlled by standard medications. Mechanistic studies in our established mouse model of glucocorticoid-induced ocular hypertension show that netarsudil both prevented and reduced intraocular pressure elevation. Further, netarsudil attenuated characteristic steroid-induced pathologies as assessed by quantification of outflow function and tissue stiffness, and morphological and immunohistochemical indicators of tissue fibrosis. Thus, rho-kinase inhibitors act directly on conventional outflow cells to prevent or attenuate fibrotic disease processes in glucocorticoid-induced ocular hypertension in an immune-privileged environment. Moreover, these data motivate the need for a randomized prospective clinical study to determine whether netarsudil is indeed superior to first-line anti-glaucoma drugs in lowering steroid-induced ocular hypertension.
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Affiliation(s)
- Guorong Li
- Department of Ophthalmology, Duke University, Durham, United States
| | - Chanyoung Lee
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, United States
| | - A Thomas Read
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, United States
| | - Ke Wang
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, United States
| | - Jungmin Ha
- Department of Mechanical Engineering, Georgia Institute of Technology, Atlanta, United States
| | - Megan Kuhn
- Department of Ophthalmology, Duke University, Durham, United States
| | - Iris Navarro
- Department of Ophthalmology, Duke University, Durham, United States
| | - Jenny Cui
- Department of Ophthalmology, Duke University, Durham, United States
| | - Katherine Young
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, United States
| | - Rahul Gorijavolu
- Department of Ophthalmology, Duke University, Durham, United States
| | - Todd Sulchek
- Department of Mechanical Engineering, Georgia Institute of Technology, Atlanta, United States
| | | | - Sina Farsiu
- Department of Ophthalmology, Duke University, Durham, United States.,Department of Biomedical Engineering, Duke University, Durham, United States
| | - John Samples
- Washington State University Floyd Elson School of Medicine, Spokane, United States
| | - Pratap Challa
- Department of Ophthalmology, Duke University, Durham, United States
| | - C Ross Ethier
- Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, United States.,Department of Mechanical Engineering, Georgia Institute of Technology, Atlanta, United States
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, United States.,Department of Biomedical Engineering, Duke University, Durham, United States
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17
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Chae JJ, Jung JH, Zhu W, Gerberich BG, Bahrani Fard MR, Grossniklaus HE, Ethier CR, Prausnitz MR. Drug-Free, Nonsurgical Reduction of Intraocular Pressure for Four Months after Suprachoroidal Injection of Hyaluronic Acid Hydrogel. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2001908. [PMID: 33511001 PMCID: PMC7816721 DOI: 10.1002/advs.202001908] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 09/14/2020] [Indexed: 06/12/2023]
Abstract
Glaucoma is the leading cause of irreversible blindness. Current treatments use drugs or surgery to reduce intraocular pressure (IOP). In this study, a drug-free, nonsurgical method is developed that lowers IOP for 4 months without requiring daily patient adherence. The approach involves expanding the suprachoroidal space (SCS) of the eye with an in situ-forming hydrogel injected using a microneedle. This study tests the hypothesis that SCS expansion increases the drainage of aqueous humor from the eye via the unconventional pathway, which thereby lowers IOP. SCS injection of a commercial hyaluronic acid (HA) hydrogel reduces the IOP of normotensive rabbits for more than 1 month and an optimized HA hydrogel formulation enables IOP reduction for 4 months. Safety assessment by clinical ophthalmic examinations indicate the treatment is well tolerated. Histopathology shows minor hemorrhage and fibrosis at the site of injection. Further analysis by ultrasound biomicroscopy demonstrates a strong correlation of IOP reduction with SCS expansion. Outflow facility measurements show no difference in pressure-dependent outflow by the conventional pathway between treated and untreated eyes, supporting the hypothesis. In conclusion, SCS expansion with an in situ-forming hydrogel can enable extended IOP reduction for treating ocular hypertension and glaucoma without drugs or surgery.
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Affiliation(s)
- J. Jeremy Chae
- School of Chemical and Biomolecular EngineeringGeorgia Institute of TechnologyAtlantaGA30332USA
| | - Jae Hwan Jung
- School of Chemical and Biomolecular EngineeringGeorgia Institute of TechnologyAtlantaGA30332USA
- Department of Pharmaceutical EngineeringDankook UniversityCheonan16890South Korea
| | - Wei Zhu
- Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory UniversityGeorgia Institute of TechnologyAtlantaGA30332USA
- Department of PharmacologySchool of PharmacyQingdao UniversityQingdao266021China
| | - Brandon G. Gerberich
- Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory UniversityGeorgia Institute of TechnologyAtlantaGA30332USA
| | | | | | - C. Ross Ethier
- Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory UniversityGeorgia Institute of TechnologyAtlantaGA30332USA
- George W. Woodruff School of Mechanical EngineeringGeorgia Institute of TechnologyAtlantaGA30332USA
| | - Mark R. Prausnitz
- School of Chemical and Biomolecular EngineeringGeorgia Institute of TechnologyAtlantaGA30332USA
- Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory UniversityGeorgia Institute of TechnologyAtlantaGA30332USA
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18
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Bhandari A, Bansal A, Sinha N. Effect of aging on heat transfer, fluid flow and drug transport in anterior human eye: A computational study. J Control Release 2020; 328:286-303. [PMID: 32861760 DOI: 10.1016/j.jconrel.2020.08.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/07/2020] [Accepted: 08/22/2020] [Indexed: 12/15/2022]
Abstract
There are a lot of geometrical and morphological changes that happen in the human eye with age. Primary open-angle glaucoma, which is caused by the increase in intraocular pressure inside the anterior chamber of the eye is also associated with the physiological aging of the eye. Therefore, it is crucial to understand the effects of aging on drug delivery in the human eye when applied topically. Consequently, a numerical model of topical drug delivery for an aging human eye has been developed using commercial software COMSOL Multiphysics in the current study. Three different age groups (young, middle and old) have been considered and the changes in geometrical and tissue properties of different domains of the eye with age have been included in the numerical model. The effect of aging on heat transfer, aqueous humor flow, intraocular pressure and drug concentration in different domains and orientations of the eye have been investigated. Additionally, an attempt has been made to predict the best class of anti-glaucomatic treatment in silico that should be preferred to treat primary open-angle glaucoma effectively. Results illustrate that there is a decrease in the average corneal temperature and an increase in the temperature deviation across the cornea with age. Further, there is a decrease in the aqueous humor flow magnitude in the anterior chamber of the eye and an increase in intraocular pressure in the anterior chamber of older age groups, which leads to primary open-angle glaucoma. The reduced aqueous humor flow leads to increased drug concentration in the anterior chamber as well as iris and reduced drug concentration in the trabecular mesh of the older age groups, thereby affecting the treatment efficacy. Additionally, our simulated results demonstrate that anti-glaucomatic treatments should be more focused on treating the trabecular mesh rather than the ciliary body of the eye.
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Affiliation(s)
- Ajay Bhandari
- Department of Mechanical Engineering, Indian Institute of Technology, Kanpur 208016, India; Department of Mechanical Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand 826004, India
| | - Ankit Bansal
- Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee 247677, India
| | - Niraj Sinha
- Department of Mechanical Engineering, Indian Institute of Technology, Kanpur 208016, India.
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19
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Wong VHY, Zhao D, Bui BV, Millar CJ, Nguyen CTO. Increased episcleral venous pressure in a mouse model of circumlimbal suture induced ocular hypertension. Exp Eye Res 2020; 202:108348. [PMID: 33166503 DOI: 10.1016/j.exer.2020.108348] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 10/29/2020] [Accepted: 11/03/2020] [Indexed: 11/30/2022]
Abstract
PURPOSE To investigate changes in aqueous humor dynamics during intraocular pressure (IOP) elevation induced by circumlimbal suture in mice. METHODS Ocular hypertension (OHT) was induced by applying a circumlimbal suture behind the limbus in male adult C57BL6/J mice. In the OHT group, the suture was left in place for an average of 8 weeks (n = 10, OHT group). In the sham control group the suture was cut at 2 days (n = 9, sham group) and in the naïve control group (n = 5) no suture was implanted. IOP was measured at baseline across 3 days, 1 h post-suture implantation, and at the chronic endpoint. Anterior segments were assessed using optical coherence tomography (OCT). Episcleral venous pressure (EVP), total outflow facility (C), uveoscleral outflow (Fu) and aqueous humor flow rate (Fin) were determined using a constant-flow infusion model. RESULTS All aqueous dynamic and chronic IOP outcome measures showed no difference between sham and naïve controls (p > 0.05) and thus these groups were combined into a single control group. IOP was elevated in OHT group compared with controls (p < 0.01). Chronic suture implantation did not change pupil size, anterior chamber depth or iridocorneal angles (p > 0.05). EVP was significantly higher in OHT eyes compared to control eyes (p < 0.01). There was no statistical difference in C, Fu and Fin between groups (p > 0.05). A significant linear correlation was found between IOP and EVP (R2 = 0.35, p = 0.001). CONCLUSIONS Circumlimbal suture implantation in mouse eyes results in chronic IOP elevation without angle closure. Chronic IOP elevation is likely to reflect higher EVP.
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Affiliation(s)
- Vickie H Y Wong
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Da Zhao
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Bang V Bui
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Cameron J Millar
- North Texas Eye Research Institute, Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Christine T O Nguyen
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, Australia.
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20
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Gonzalez LE, Boylan PM. Netarsudil for the Treatment of Open-Angle Glaucoma and Ocular Hypertension: A Literature Review. Ann Pharmacother 2020; 55:1025-1036. [DOI: 10.1177/1060028020971215] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Objective: To evaluate netarsudil’s role as first-line therapy for the treatment of open-angle glaucoma (OAG) and ocular hypertension (OHT). Data Sources: A literature search utilizing MEDLINE and CINAHL was performed using netarsudil and AR-13324 as keywords. Studies published from January 1970 to September 2020 were eligible. Study Selection and Data Extraction: For inclusion, articles were required to be published in English and participants enrolled in phase I, II, or III clinical trials. Articles were excluded if netarsudil was coformulated with another medication. Preclinical research, case reports, case series, review articles, citations without an abstract, and newsletters were excluded. Literature Review: The search retrieved 97 unique citations; 90 results were excluded, and 7 studies were included for analysis. Relevance to Patient Care and Clinical Practice: In all, 20 years elapsed between the Food and Drug Administration’s approvals of distinct medications to treat OAG. Existing first-line therapies target the uveoscleral pathway, which is responsible for a small amount of aqueous humor outflow. Rho kinase inhibitors target the trabecular pathway, which is responsible for 90% of aqueous humor outflow; thus, Rho kinase inhibitors may significantly reduce intraocular pressure and improve clinical outcomes for patients with OAG or OHT. Conclusions: Evidence demonstrates that netarsudil is inferior to prostaglandin analogues and noninferior to topical β-blockers in the treatment of OAG and OHT. Hyperemia is a common adverse drug reaction, which often resolves after medication discontinuation. Additional phase III clinical trials and evidence-based guidelines are necessary to determine netarsudil’s position in OAG and OHT management.
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Affiliation(s)
| | - Paul M. Boylan
- The University of Oklahoma Health Sciences Center College of Pharmacy, Oklahoma City, OK, USA
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21
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Lee JY, Akiyama G, Saraswathy S, Xie X, Pan X, Hong YK, Huang AS. Aqueous humour outflow imaging: seeing is believing. Eye (Lond) 2020; 35:202-215. [PMID: 33060830 DOI: 10.1038/s41433-020-01215-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/27/2020] [Accepted: 09/29/2020] [Indexed: 12/22/2022] Open
Abstract
Elevated intraocular pressure (IOP) is the primary risk factor for blindness in glaucoma. IOP is determined by many factors including aqueous humour production and aqueous humour outflow (AHO), where AHO disturbance represents the primary cause of increased IOP. With the recent development of new IOP lowering drugs and Minimally Invasive Glaucoma Surgeries (MIGS), renewed interest has arisen in shedding light on not only how but where AHO is occurring for the trabecular/conventional, uveoscleral/unconventional, and subconjunctival outflow pathways. Historical studies critical to understanding outflow anatomy will be presented, leading to the development of modern imaging methods. New biological behaviours uncovered by modern imaging methods will be discussed with relevance to glaucoma therapies emphasized.
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Affiliation(s)
- Jong Yeon Lee
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,Department of Ophthalmology, Gachon University, College of Medicine, Gil Medical Center, Incheon, Korea
| | - Goichi Akiyama
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,Jikei School of Medicine, Tokyo, Japan.,Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Sindhu Saraswathy
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Xiaobin Xie
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,Eye Hospital of China Academy of Chinese Medical Sciences, Beijing, China
| | - Xiaojing Pan
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.,Qindao Eye Hospital of Shandong First Medical University, Shandong Eye Institute, Qindao, China
| | - Young-Kwon Hong
- Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Alex S Huang
- Doheny Eye Institute and Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA.
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22
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Smith DW, Lee CJ, Gardiner BS. Estimating outflow facility parameters for the human eye using hypotensive pressure-time data. PLoS One 2020; 15:e0238146. [PMID: 32841295 PMCID: PMC7447060 DOI: 10.1371/journal.pone.0238146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 08/10/2020] [Indexed: 11/18/2022] Open
Abstract
We have previously developed a new theory for pressure dependent outflow from the human eye, and tested the model using experimental data at intraocular pressures above normal eye pressures. In this paper, we use our model to analyze a hypotensive pressure-time dataset obtained following application of a Honan balloon. Here we show that the hypotensive pressure-time data can be successfully analyzed using our proposed pressure dependent outflow model. When the most uncertain initial data point is removed from the dataset, then parameter estimates are close to our previous parameter estimates, but clearly parameter estimates are very sensitive to assumptions. We further show that (i) for a measured intraocular pressure-time curve, the estimated model parameter for whole eye surface hydraulic conductivity is primarily a function of the ocular rigidity, and (ii) the estimated model parameter that controls the rate of decrease of outflow with increasing pressure is primarily a function of the convexity of the monotonic pressure-time curve. Reducing parameter uncertainty could be accomplished using new technologies to obtain higher quality datasets, and by gathering additional data to better define model parameter ranges for the normal eye. With additional research, we expect the pressure dependent outflow analysis described herein may find applications in the differential diagnosis, prognosis and monitoring of the glaucomatous eye.
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Affiliation(s)
- David W. Smith
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Crawley, Australia
| | - Chang-Joon Lee
- College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Western Australia, Australia
| | - Bruce S. Gardiner
- College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Western Australia, Australia
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23
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Ghate D, Kedar S, Havens S, Fan S, Thorell W, Nelson C, Gu L, Tong J, Gulati V. The Effects of Acute Intracranial Pressure Changes on the Episcleral Venous Pressure, Retinal Vein Diameter and Intraocular Pressure in a Pig Model. Curr Eye Res 2020; 46:524-531. [PMID: 32806985 DOI: 10.1080/02713683.2020.1805769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE Orbital veins such as the retinal veins and episcleral veins drain into the cavernous sinus, an intracranial venous structure. We studied the effects of acute intracranial pressure (ICP) elevation on episcleral venous pressure, intraocular pressure and retinal vein diameter in an established non-survival pig model. METHODS In six adult female domestic pigs, we increased ICP in 5 mm Hg increments using saline infusion through a lumbar drain. We measured ICP (using parenchymal pressure monitor), intraocular pressure (using pneumatonometer), episcleral venous pressure (using venomanometer), retinal vein diameter (using OCT images) and arterial blood pressure at each stable ICP increment. The average baseline ICP was 5.4 mm Hg (range 1.5-9 mm Hg) and the maximum stable ICP ranged from 18 to 40 mm Hg. Linear mixed models with random intercepts were used to evaluate the effect of acute ICP increase on outcome variables. RESULTS With acute ICP elevation, we found loss of retinal venous pulsation and increased episcleral venous pressure, intraocular pressure and retinal vein pressure in all animals. Specifically, acute ICP increase was significantly associated with episcleral venous pressure (β = 0.31; 95% CI 0.14-0.48, p < .001), intraocular pressure (β = 0.37, 95%CI 0.24-0.50; p < .001) and retinal vein diameter (β = 11.29, 95%CI 1.57-21.00; p = .03) after controlling for the effects of arterial blood pressure. CONCLUSION We believe that the ophthalmic effects of acute ICP elevation are mediated by increased intracranial venous pressure producing upstream pressure changes within the orbital and retinal veins. These results offer exciting possibilities for the development of non-invasive ophthalmic biomarkers to estimate acute ICP elevations following significant neuro-trauma.
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Affiliation(s)
- Deepta Ghate
- Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sachin Kedar
- Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, USA.,Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Shane Havens
- Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, USA
| | - Shan Fan
- Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, USA
| | - William Thorell
- Department of Neurosurgery, University of Nebraska Medical Center, Omaha, NE, USA
| | - Carl Nelson
- Department of Mechanical Engineering, University of Nebraska, Lincoln, NE, USA
| | - Linxia Gu
- Department of Mechanical Engineering, University of Nebraska, Lincoln, NE, USA.,Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, USA
| | - Junfei Tong
- Department of Mechanical Engineering, University of Nebraska, Lincoln, NE, USA
| | - Vikas Gulati
- Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE, USA
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24
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Lee SS, Robinson MR, Weinreb RN. Episcleral Venous Pressure and the Ocular Hypotensive Effects of Topical and Intracameral Prostaglandin Analogs. J Glaucoma 2020; 28:846-857. [PMID: 31261285 PMCID: PMC6735525 DOI: 10.1097/ijg.0000000000001307] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
There is a limit beyond which increasing either the concentration of a prostaglandin analog (PGA) or its dosing frequency fails to produce increases in ocular hypotensive efficacy with topical dosing. Intracameral PGA dosing with a bimatoprost implant, however, does not exhibit the same intraocular pressure (IOP)-lowering plateau at studied concentrations, and the maximum-achievable ocular hypotensive effects are not yet known. This suggests that the bimatoprost intracameral implant may activate another mechanism of action in addition to the mechanism(s) activated by topical application. Episcleral venous pressure (EVP) is a key determinant of IOP, and experimental manipulation of the episcleral vasculature can change both EVP and IOP. The recent observation that topical and intracameral PGA drug delivery routes produce different patterns of conjunctival hyperemia suggested that the differences in the IOP-lowering profiles may be caused by differing effects on the episcleral vasculature. Recent experiments in animals have shown that topical PGAs increase EVP, while the bimatoprost intracameral implant causes a smaller, transient increase in EVP, followed by a sustained decrease. The increase in EVP could be limiting the IOP-lowering efficacy of topical PGAs. In contrast, the decrease in EVP associated with the bimatoprost implant could explain its enhanced IOP-lowering effects. Further research on EVP as a target for IOP lowering is indicated to improve our understanding of this potentially important pathway for treating patients with glaucoma.
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Affiliation(s)
| | | | - Robert N Weinreb
- Viterbi Family Department of Ophthalmology, Hamilton Glaucoma Center, Shiley Eye Institute, University of California, San Diego, La Jolla, CA
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25
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Saraswathy S, Bogarin T, Barron E, Francis BA, Tan JCH, Weinreb RN, Huang AS. Segmental differences found in aqueous angiographic-determined high - and low-flow regions of human trabecular meshwork. Exp Eye Res 2020; 196:108064. [PMID: 32439396 DOI: 10.1016/j.exer.2020.108064] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 01/28/2023]
Abstract
This work sought to compare aqueous angiographic segmental patterns with bead-based methods which directly visualize segmental trabecular meshwork (TM) tracer trapping. Additionally, segmental protein expression differences between aqueous angiographic-derived low- and high-outflow human TM regions were evaluated. Post-mortem human eyes (One Legacy and San Diego eye banks; n = 15) were perfused with fluorescent tracers (fluorescein [2.5%], indocyanine green [0.4%], and/or fluorescent microspheres). After angiographic imaging (Spectralis HRA+OCT; Heidelberg Engineering), peri-limbal low- and high-angiographic flow regions were marked. Aqueous angiographic segmental outflow patterns were similar to fluorescent microsphere TM trapping segmental patterns. TM was dissected from low- and high-flow areas and processed for immunofluorescence or Western blot and compared. Versican expression was relatively elevated in low-flow regions while MMP3 and collagen VI were relatively elevated in high-flow regions. TGF-β2, thrombospondin-1, TGF-β receptor1, and TGF-β downstream proteins such as α-smooth muscle actin were relatively elevated in low-flow regions. Additionally, fibronectin (FN) levels were unchanged, but the EDA isoform (FN-EDA) that is associated with fibrosis was relatively elevated in low-flow regions. These results show that segmental aqueous angiographic patterns are reflective of underlying TM molecular characteristics and demonstrate increased pro-fibrotic activation in low-flow regions. Thus, we provide evidence that aqueous angiography outflow visualization, the only tracer outflow imaging method available to clinicians, is in part representative of TM biology.
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Affiliation(s)
- Sindhu Saraswathy
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Thania Bogarin
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Ernesto Barron
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Brian A Francis
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - James C H Tan
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Robert N Weinreb
- Hamilton Glaucoma Center, Shiley Eye Institute, Viterbi Family Department of Ophthalmology University of California, San Diego, CA, USA
| | - Alex S Huang
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
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26
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Smith DW, Lee CJ, Gardiner BS. No flow through the vitreous humor: How strong is the evidence? Prog Retin Eye Res 2020; 78:100845. [PMID: 32035123 DOI: 10.1016/j.preteyeres.2020.100845] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 01/30/2020] [Accepted: 02/03/2020] [Indexed: 02/06/2023]
Abstract
When analyzing vitreal drug delivery, or the pharmacological effects of drugs on intraocular pressure, or when interpreting outflow facility measurements, it is generally accepted that the fluid in the vitreous humor is stagnant. It is accepted that for all practical purposes, the aqueous fluid exits the eye via anterior pathways only, and so there is negligible if any posteriorly directed flow of aqueous through the vitreous humor. This assumption is largely based on the interpretation of experimental data from key sources including Maurice (1957), Moseley (1984), Gaul and Brubaker (1986), Maurice (1987) and Araie et al. (1991). However, there is strong independent evidence suggesting there is a substantial fluid flow across the retinal pigment epithelium from key sources including Cantrill and Pederson (1984), Chihara and Nao-i, Tsuboi (1985), Dahrouj et al. (2014), Smith and Gardiner (2017) and Smith et al. (2019). The conflicting evidence creates a conundrum-how can both interpretations be true? This leads us to re-evaluate the evidence. We demonstrate that the data believed to be supporting no aqueous flow through the vitreous are in fact compatible with a significant normal aqueous flow. We identify strong and independent lines of evidence supporting fluid flow across the RPE, including our new outflow model for the eye. On balance it appears the current evidence favors the view that there is normally a significant aqueous flow across the RPE in vivo. This finding suggests that past and future analyses of outflow facility, interpretations of some drug distributions and the interpretation of some drug effects on eye tissues, may need to be revised.
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Affiliation(s)
- David W Smith
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Australia.
| | - Chang-Joon Lee
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Australia; College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Western Australia, Australia
| | - Bruce S Gardiner
- College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Western Australia, Australia
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27
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Ficarrotta KR, Passaglia CL. Intracranial pressure modulates aqueous humour dynamics of the eye. J Physiol 2020; 598:403-413. [PMID: 31769030 DOI: 10.1113/jp278768] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 11/22/2019] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS An elevation in intracranial pressure (ICP) lowers conventional outflow facility (increases aqueous outflow resistance) of rat eyes. The reduction in outflow facility correlates with an increase in intraocular pressure (IOP). The effect of ICP elevation on outflow facility and IOP is blocked by TTX. The results indicate that aqueous humour dynamics is modulated by ICP-driven neural feedback from the brain. This feedback mechanism may act to stabilize translaminar pressure across the optic nerve head and may provide a new avenue for glaucoma therapy. ABSTRACT While intraocular pressure (IOP) is a well-known risk factor for glaucoma, intracranial pressure (ICP) is attracting heightened interest because of its influence on optic nerve head biomechanics. Studies have shown that ICP can have marked impacts on posterior eye health by modifying the translaminar pressure gradient across the optic nerve. There is also growing evidence that IOP and ICP may be interconnected, although the mechanism of their putative interaction is unknown. We sought to test the hypothesis that ICP modulates IOP by altering aqueous humour dynamics. The anterior chamber and lateral ventricle of anaesthetized Brown-Norway rats were cannulated with fine-gauge needles connected to a programmable pump and saline reservoir, respectively. ICP was manipulated by varying reservoir height, and eye outflow facility (C) was determined from the pump flow rate required to hold IOP at different levels. C was 22 ± 4 nl/min/mmHg at resting ICP and 13 ± 3 nl/min/mmHg when ICP was raised 15 mmHg, a reduction of 41 ± 13% (n = 18). The decrease in outflow facility was independent of blood pressure, reversible, scaled with ICP elevation and correlated with increases in resting IOP. It was physiological in origin because C returned to baseline values after the rats were killed and corneal application of TTX though ICP remained elevated. These results indicate that a neural feedback mechanism driven by ICP regulates conventional outflow facility in rats. The mechanism may protect the eye from translaminar pressure swings and may offer a new target for glaucoma treatment.
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Affiliation(s)
- Kayla R Ficarrotta
- Medical Engineering Department, University of South Florida, Tampa, FL, 33620, USA
| | - Christopher L Passaglia
- Medical Engineering Department, University of South Florida, Tampa, FL, 33620, USA.,Ophthalmology Department, University of South Florida, Tampa, FL, 33620, USA
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28
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Similar Performance of Trabectome and Ahmed Glaucoma Devices in a Propensity Score-matched Comparison. J Glaucoma 2019; 27:490-495. [PMID: 29613976 DOI: 10.1097/ijg.0000000000000960] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To apply propensity score matching to Ahmed glaucoma drainage implants (AGI) to trabectome-mediated ab interno trabeculectomy (AIT). Recent data suggest that AIT can produce results similar to AGI traditionally reserved for more severe glaucoma. METHODS AGI and AIT patients with at least 1 year of follow-up were included. The primary outcome measures were intraocular pressure (IOP), glaucoma medications, and a Glaucoma Index (GI) score. GI reflected glaucoma severity based on visual field, the number of preoperative medications, and preoperative IOP. Score matching used a genetic algorithm consisting of age, sex, type of glaucoma, concurrent phacoemulsification, baseline number of medications, and baseline IOP. Patients without a close match were excluded. RESULTS Of 152 patients, 34 AIT patients were matched to 32 AGI patients. Baseline characteristics including ethnicity, IOP, the number of medications, glaucoma type, the degree of visual field loss and GI were not significantly different between AIT and AGI. AIT had a preoperative IOP of 23.6±8.1 mm Hg compared with 26.5+10.6 mm Hg for AGI. At 12 months, the mean IOP was 15.0±9 mm Hg for AIT versus 15.0±4 mm Hg for AGI (P=0.8), whereas the number of drops was 2.3±2.2 for AIT versus 3.6±1.3 for AGI (P=0.016). Only 6 AIT patients (17.6%) required further surgery within the first 12 months versus 9 (28%) for AGI. Success, defined as IOP<21 mm Hg, <20% reduction and no reoperation, was achieved in 76% of AIT versus 69% of AGI (P=0.48). Complications occurred in 13% of AGI and 0.8% of AIT. CONCLUSIONS A propensity score-matched comparison of AIT and AGI showed an equivalent IOP reduction through 1 year. Surprisingly, the AGI group required more glaucoma medications than the AIT group at 6 and 12 months.
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29
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Lee RMH, Bouremel Y, Eames I, Brocchini S, Khaw PT. Translating Minimally Invasive Glaucoma Surgery Devices. Clin Transl Sci 2019; 13:14-25. [PMID: 31568666 PMCID: PMC6951459 DOI: 10.1111/cts.12660] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 05/08/2019] [Indexed: 11/30/2022] Open
Abstract
Glaucoma is the leading cause of irreversible blindness with over 70 million people affected worldwide. The surgical management of glaucoma aims to lower intraocular pressure by increasing aqueous outflow facility. The latest manufacturing techniques have allowed for the development of a number of novel implantable devices to improve safety and outcomes of glaucoma surgery. These are collectively referred to as minimally invasive glaucoma surgery (MIGS) devices and are among the smallest devices implanted in the human body. This review discusses the design criterion and constraints as well as the user requirements for MIGS devices. We review how recent devices have attempted to meet these challenges and give our opinion as to the necessary characteristics for the development of future devices.
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Affiliation(s)
- Richard M H Lee
- Chelsea and Westminster Hospital NHS Foundation Trust, London, UK.,NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
| | - Yann Bouremel
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
| | - Ian Eames
- UCL Department of Mechanical Engineering, London, UK
| | - Steve Brocchini
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK.,UCL School of Pharmacy, London, UK
| | - Peng Tee Khaw
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
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30
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Taskar PS, Patil A, Lakhani P, Ashour E, Gul W, ElSohly MA, Murphy B, Majumdar S. Δ 9-Tetrahydrocannabinol Derivative-Loaded Nanoformulation Lowers Intraocular Pressure in Normotensive Rabbits. Transl Vis Sci Technol 2019; 8:15. [PMID: 31588378 PMCID: PMC6753841 DOI: 10.1167/tvst.8.5.15] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/10/2019] [Indexed: 01/10/2023] Open
Abstract
PURPOSE Δ9-Tetrahydrocannabinol-valine-hemisuccinate, a hydrophilic prodrug of Δ9-tetrahydrocannabinol, synthesized with the aim of improving the ocular bioavailability of the parent molecule, was investigated in a lipid-based nanoparticle dosage form for ocular delivery. METHODS Solid lipid nanoparticles (SLNs) of Δ9-tetrahydrocannabinol-valine-hemisuccinate and Δ9-tetrahydrocannabinol, along with a nanoemulsion of Δ9-tetrahydrocannabinol-valine-hemisuccinate, were tested for glaucoma management in a normotensive rabbit model by using a multiple-dosing protocol. Marketed formulations of timolol maleate and pilocarpine HCl were also tested for their pharmacodynamic profile, post-single dose administration. RESULTS A peak intraocular pressure (IOP) drop of 30% from baseline was observed in rabbits treated with SLNs loaded with Δ9-tetrahydrocannabinol-valine-hemisuccinate at 90 minutes. Treated eyes of rabbits receiving Δ9-tetrahydrocannabinol-valine-hemisuccinate SLNs had significantly lower IOP than untreated eyes until 360 minutes, whereas the group receiving the emulsion formulation showed a drop in IOP until 90 minutes only. In comparison to marketed pilocarpine and timolol maleate ophthalmic solutions, Δ9-tetrahydrocannabinol-valine-hemisuccinate SLNs produced a greater effect on IOP in terms of both intensity and duration. In terms of tissue concentrations, significantly higher concentrations of Δ9-tetrahydrocannabinol-valine-hemisuccinate were observed in iris-ciliary bodies and retina-choroid with SLNs. CONCLUSION Δ9-Tetrahydrocannabinol-valine-hemisuccinate formulated in a lipid-based nanoparticulate carrier shows promise in glaucoma pharmacotherapy. TRANSLATIONAL RELEVANCE Glaucoma therapies usually focus on decreased aqueous humor production and increased outflow. However, such therapy is not curative, and there lies a need in preclinical research to focus efforts on agents that not only affect the aqueous humor dynamics but also provide neuroprotection. Historically, there have been bench-scale studies looking at retinal ganglion cell death post-axonal injury. However, for a smooth translation of this in vitro activity to the clinic, animal models examining IOP reduction, i.e., connecting the neuroprotective activity to a measurable outcome in glaucoma management (IOP), need to be investigated. This study investigated the IOP reduction efficacy of cannabinoids for glaucoma pharmacotherapy in a normotensive rabbit model, bringing forth a new class of agents with the potential of IOP reduction and improved permeation to the back of the eye, possibly providing neuroprotective benefits in glaucoma management.
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Affiliation(s)
- Pranjal S Taskar
- Department of Pharmaceutics and Drug Delivery, University of Mississippi, Oxford, MS, USA
- Research Institute of Pharmaceutical Sciences, University of Mississippi, Oxford, MS, USA
| | - Akash Patil
- Department of Pharmaceutics and Drug Delivery, University of Mississippi, Oxford, MS, USA
- Research Institute of Pharmaceutical Sciences, University of Mississippi, Oxford, MS, USA
| | - Prit Lakhani
- Department of Pharmaceutics and Drug Delivery, University of Mississippi, Oxford, MS, USA
- Research Institute of Pharmaceutical Sciences, University of Mississippi, Oxford, MS, USA
| | - Eman Ashour
- Department of Pharmaceutics and Drug Delivery, University of Mississippi, Oxford, MS, USA
- Research Institute of Pharmaceutical Sciences, University of Mississippi, Oxford, MS, USA
| | - Waseem Gul
- ElSohly Laboratories Inc., Oxford, MS, USA
| | - Mahmoud A ElSohly
- Department of Pharmaceutics and Drug Delivery, University of Mississippi, Oxford, MS, USA
- Research Institute of Pharmaceutical Sciences, University of Mississippi, Oxford, MS, USA
- ElSohly Laboratories Inc., Oxford, MS, USA
| | | | - Soumyajit Majumdar
- Department of Pharmaceutics and Drug Delivery, University of Mississippi, Oxford, MS, USA
- Research Institute of Pharmaceutical Sciences, University of Mississippi, Oxford, MS, USA
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31
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Wang Q, Thau A, Levin AV, Lee D. Ocular hypotony: A comprehensive review. Surv Ophthalmol 2019; 64:619-638. [PMID: 31029581 DOI: 10.1016/j.survophthal.2019.04.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 04/11/2019] [Accepted: 04/15/2019] [Indexed: 02/08/2023]
Abstract
Ocular hypotony is an infrequent, yet potentially vision-threatening, entity. The list of differential causes is extensive, involving any condition that may compromise aqueous humor dynamics or the integrity of the globe and sometimes following medical treatments or procedures. Depending on the cause and the clinical impact, treatment options aim to correct the underlying pathology and to reestablish anatomical integrity, as well as visual function. We review the pathophysiology, clinical presentation, different causes, and associated therapeutic options of ocular hypotony.
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Affiliation(s)
- Qianqian Wang
- Wills Eye Hospital, Philadelphia, Pennsylvania, USA; Department of Ophthalmology, University of Montreal Hospital Center, Montreal Quebec, Canada
| | - Avrey Thau
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Alex V Levin
- Wills Eye Hospital, Philadelphia, Pennsylvania, USA; Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Daniel Lee
- Wills Eye Hospital, Philadelphia, Pennsylvania, USA; Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
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32
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Outflow facility and extent of angle closure in a porcine model. Graefes Arch Clin Exp Ophthalmol 2019; 257:1239-1245. [PMID: 30944988 DOI: 10.1007/s00417-019-04279-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 01/29/2019] [Accepted: 02/15/2019] [Indexed: 12/19/2022] Open
Abstract
PURPOSE To establish the extent of anterior chamber angle circumference needed to maintain a physiological outflow facility (C). This could create a model to investigate focal outflow regulation. METHODS Twenty anterior segments of porcine eyes were assigned to five groups, each with a different degree of cyanoacrylate-mediated angle closure: 90° (n = 4), 180° (n = 4), 270° (n = 4), 360° (n = 4), and four unoccluded control eyes. The outflow facility was measured at baseline, 3, 12, 24, and 36 h after angle closure. Outflow patterns were evaluated with canalograms and the histomorphology was compared. RESULTS Baseline outflow facilities of the five groups were similar (F = 0.922, p = 0.477). Occlusion of 360° induced a significant decrease in facility from baseline at all time-points (p ≤ 0.023 at 3, 12, 24, and 36 h). However, no difference from baseline was found in any of the partially occluded (0-270°) groups (F ≥ 0.067, p ≥ 0.296 at 3, 12, 24, and 36 h). The canalograms confirmed the extent of occlusion with flow through the unblocked regions. Histology revealed no adverse effects of blockage on the TM or aqueous plexus in the unoccluded angle portions. The unoccluded TM appeared normal. CONCLUSION Cyanoacrylate-mediated angle occlusion created a reproducible angle closure model. Ninety degrees of unoccluded anterior chamber angle circumference was sufficient to maintain physiological outflow. This model may help understand how outflow can be regulated in healthy, nonglaucomatous TM.
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33
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Calculus and tear flow. Ocul Surf 2019; 17:365-368. [DOI: 10.1016/j.jtos.2019.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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34
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Killer HE, Hou R, Wostyn P, Meyer P, Pircher A. Pressure and velocity in intraocular and subarachnoid space fluid chambers: an inseparable couple. Eye (Lond) 2019; 33:343-346. [DOI: 10.1038/s41433-018-0231-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 09/17/2018] [Indexed: 11/09/2022] Open
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35
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Ficarrotta KR, Bello SA, Mohamed YH, Passaglia CL. Aqueous Humor Dynamics of the Brown-Norway Rat. Invest Ophthalmol Vis Sci 2019; 59:2529-2537. [PMID: 29847660 PMCID: PMC5967599 DOI: 10.1167/iovs.17-22915] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The study aimed to provide a quantitative description of aqueous humor dynamics in healthy rat eyes. Methods One eye of 26 anesthetized adult Brown-Norway rats was cannulated with a needle connected to a perfusion pump and pressure transducer. Pressure-flow data were measured in live and dead eyes by varying pump rate (constant-flow technique) or by modulating pump duty cycle to hold intraocular pressure (IOP) at set levels (modified constant-pressure technique). Data were fit by the Goldmann equation to estimate conventional outflow facility (\begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}C\end{document}) and unconventional outflow rate (\begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}{F_{un}}\end{document}). Parameter estimates were respectively checked by inserting a shunt of similar conductance into the eye and by varying eye hydration methodology. Results Rat IOP averaged 14.6 ± 1.9 mm Hg at rest. Pressure-flow data were repeatable and indistinguishable for the two perfusion techniques, yielding \begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}C\end{document} = 0.023 ± 0.002 μL/min/mm Hg and \begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}{F_{un}}\end{document} = 0.096 ± 0.024 μL/min. \begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}C\end{document} was similar for live and dead eyes and increased upon shunt insertion by an amount equal to shunt conductance, validating measurement accuracy. At 100% humidity \begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}{F_{un}}\end{document} dropped to 0.003 ± 0.030 μL/min. Physiological washout was not observed (−0.35 ± 0.65%/h), and trabecular anatomy looked normal. Conclusions Rat aqueous humor dynamics are intermediate in magnitude compared to those in mice and humans, consistent with species differences in eye size. \begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}C\end{document} does not change with time or death. Evaporation complicates measurement of \begin{document}\newcommand{\bialpha}{\boldsymbol{\alpha}}\newcommand{\bibeta}{\boldsymbol{\beta}}\newcommand{\bigamma}{\boldsymbol{\gamma}}\newcommand{\bidelta}{\boldsymbol{\delta}}\newcommand{\bivarepsilon}{\boldsymbol{\varepsilon}}\newcommand{\bizeta}{\boldsymbol{\zeta}}\newcommand{\bieta}{\boldsymbol{\eta}}\newcommand{\bitheta}{\boldsymbol{\theta}}\newcommand{\biiota}{\boldsymbol{\iota}}\newcommand{\bikappa}{\boldsymbol{\kappa}}\newcommand{\bilambda}{\boldsymbol{\lambda}}\newcommand{\bimu}{\boldsymbol{\mu}}\newcommand{\binu}{\boldsymbol{\nu}}\newcommand{\bixi}{\boldsymbol{\xi}}\newcommand{\biomicron}{\boldsymbol{\micron}}\newcommand{\bipi}{\boldsymbol{\pi}}\newcommand{\birho}{\boldsymbol{\rho}}\newcommand{\bisigma}{\boldsymbol{\sigma}}\newcommand{\bitau}{\boldsymbol{\tau}}\newcommand{\biupsilon}{\boldsymbol{\upsilon}}\newcommand{\biphi}{\boldsymbol{\phi}}\newcommand{\bichi}{\boldsymbol{\chi}}\newcommand{\bipsi}{\boldsymbol{\psi}}\newcommand{\biomega}{\boldsymbol{\omega}}{F_{un}}\end{document} even when eyes are not enucleated. Absence of washout is a notable finding seen only in mouse and human eyes to date.
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Affiliation(s)
- Kayla R Ficarrotta
- Chemical and Biomedical Engineering Department, University of South Florida, Tampa, Florida, United States
| | - Simon A Bello
- Electrical Engineering Department, University of South Florida, Tampa, Florida, United States
| | - Youssef H Mohamed
- Chemical and Biomedical Engineering Department, University of South Florida, Tampa, Florida, United States
| | - Christopher L Passaglia
- Chemical and Biomedical Engineering Department, University of South Florida, Tampa, Florida, United States.,Ophthalmology Department, University of South Florida, Tampa, Florida, United States
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36
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Anderson AP, Butterfield JS, Subramanian PS, Clark TK. Intraocular pressure and cardiovascular alterations investigated in artificial gravity as a countermeasure to spaceflight associated neuro-ocular syndrome. J Appl Physiol (1985) 2018; 125:567-576. [PMID: 29745798 DOI: 10.1152/japplphysiol.00082.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Artificial gravity (AG) has been proposed as a countermeasure to spaceflight-associated neuro-ocular syndrome (SANS). The etiology of SANS is unknown but mimicking gravitational loading through AG may mitigate these negative adaptations. Seventeen subjects (nine men, eight women; 18-32 yr) were analyzed in four experimental conditions: 1) standing, 2) supine, 3) AG with the center of rotation at the eye (AGEC), and 4) AG with 2 Gs at the feet (AG2G). In both AG conditions, subjects were spun to produce 1 G at their center of mass. Data included self-administered intraocular pressure (IOP, Tono-pen AVIA, Depew, NY), heart rate (HR), and mean arterial blood pressure (MAP, Omron Series 10, Omron Healthcare, Kyoto, Japan). Data were analyzed with repeated measures ANOVAs with Tukey-Kramer corrections for multiple pairwise comparisons. IOP was 15.7 ± 1.4 mmHg (mean ± 95% confidence interval) standing, 18.8 ± 1.3 mmHg supine, 18.5 ± 1.7 mmHg in AGEC, and 17.5 ± 1.5 mmHg in AG2G. Postures showed a main effect [F(3,48) = 11.0, P < 0.0005], with standing significantly lower than supine ( P = 0.0009), AGEC ( P = 0.002), and AG2G (0.036). Supine, AGEC, and AG2G were not statistically different. HR and MAP were lower in supine compared with all other postures ( P = 0.002 to P < 0.0005), but there were no differences between standing, AGEC, and AG2G. IOP in supine and standing was consistent with previous studies, but contrary to our hypothesis, remained elevated in both AG conditions. Cardiovascular parameters and hydrostatic gradients determine IOP, which remain unchanged compared with standing. These results suggest additional influence on IOP from previously unconsidered factors. NEW & NOTEWORTHY This is the first study, to the authors' knowledge, to measure intraocular pressure in short-radius centrifuge artificial gravity (AG), which has been proposed as a countermeasure to the spaceflight-associated neuro-ocular syndrome (SANS). If the etiology of SANS is related to intraocular pressure, these results have implications for whether or not short-radius AG can be used to prevent ocular changes relevant to it. Our results indicate this proposed countermeasure merits further investigation.
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Affiliation(s)
- Allison P Anderson
- Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Colorado
| | - Joseph S Butterfield
- Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Colorado.,Department of Integrative Physiology, University of Colorado Boulder, Colorado
| | | | - Torin K Clark
- Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder, Colorado
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37
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Alaghband P, Beltran-Agulló L, Galvis EA, Overby DR, Lim KS. Effect of phacoemulsification on facility of outflow. Br J Ophthalmol 2018; 102:1520-1526. [PMID: 29654113 PMCID: PMC6241621 DOI: 10.1136/bjophthalmol-2017-311548] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 01/15/2018] [Accepted: 01/19/2018] [Indexed: 11/24/2022]
Abstract
Purpose Phacoemulsification has been shown to reduce intraocular pressure (IOP). The mechanism of action is thought to be via increased trabecular outflow facility. However, studies on the relationship between phacoemulsification and outflow facility have been inconsistent. This study intended to examine the change in electronic Schiotz tonographic outflow facility (TOF) and IOP measurements following phacoemulsification. Methods Patients who were due to undergo a standard clear corneal incision phacoemulsification with intraocular lens (IOL) implantation, at St Thomas’ Hospital, were invited to participate in this study. IOP was measured using Goldmann’s applanation tonometer, and TOF was measured by electronic Schiotz tonography at baseline and at 3, 6 and 12 months postoperatively. Results Forty-one patients were recruited. Tonography data for 27 patients were reliable and available at all time points. Eleven cases had primary open angle glaucoma and cataract, while 16 patients had cataract only. Mean IOP reduced at every time point postoperatively significantly compared with baseline. TOF improved significantly after cataract extraction at all time points (baseline of 0.14±0.06 vs 0.18±0.09 at 3 months, P=0.02 and 0.20±0.09 at 6 months, P=0.003, 0.17±0.07 µL/min mmHg at 12 months, P=0.04). Five contralateral eyes of patients with cataracts only who did not have any intraocular surgery during the follow-up period were used as comparison. Their IOP and TOF did not change significantly at any postoperative visits. Conclusion This is the first study using electronic Schiotz tonography with documented anterior chamber depth and gonioscopy after modern cataract surgery (CS) with phacoemulsification and IOL implantation. We demonstrated that phacoemulsification increases TOF and this fully accounts for the IOP reduction following CS. ISTCRN registration number ISRCTN04247738.
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Affiliation(s)
- Pouya Alaghband
- Ophthalmology, St Thomas' Hospital, London, UK.,Academic ophthalmology, King's College London, London, UK
| | - Laura Beltran-Agulló
- Ophthalmology, St Thomas' Hospital, London, UK.,Ophthalmology, Institut Català de la Retina, Barcelona, Spain
| | | | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London, UK
| | - Kin Sheng Lim
- Ophthalmology, St Thomas' Hospital, London, UK.,Academic ophthalmology, King's College London, London, UK
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38
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Kazemi A, McLaren JW, Kopczynski CC, Heah TG, Novack GD, Sit AJ. The Effects of Netarsudil Ophthalmic Solution on Aqueous Humor Dynamics in a Randomized Study in Humans. J Ocul Pharmacol Ther 2018; 34:380-386. [PMID: 29469601 PMCID: PMC5995263 DOI: 10.1089/jop.2017.0138] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE Netarsudil, an inhibitor of Rho kinase and a norepinephrine transporter, has been shown to lower elevated intraocular pressure (IOP) in controlled studies of patients with open-angle glaucoma and ocular hypertension, and in healthy volunteers. The mechanism of this ocular hypotensive effect in humans is unknown. METHODS The objective of this study was to evaluate the effect of netarsudil 0.02% on aqueous humor dynamics (AHD) parameters. In this double-masked, vehicle-controlled, paired-eye comparison study, 11 healthy volunteers received topical netarsudil ophthalmic solution 0.02% or its vehicle once daily for 7 days (morning dosing). The primary endpoints were the change in AHD parameters, compared between active and vehicle-treated eyes. RESULTS In netarsudil-treated eyes, diurnal outflow facility increased from 0.27 ± 0.10 μL/min/mmHg to 0.33 ± 0.11 μL/min/mmHg (+22%; P = 0.02) after 7 days of treatment. In placebo-treated eyes, diurnal outflow facility did not significantly change (P = 0.94). The difference between netarsudil and placebo eyes in diurnal change of outflow facility was 0.08 μL/min/mmHg (P < 0.001). Diurnal episcleral venous pressure (EVP) in netarsudil-treated eyes decreased from 7.9 ± 1.2 mmHg to 7.2 ± 1.8 (-10%; P = 0.01). Diurnal EVP was not significantly different between netarsudil- and placebo-treated eyes. There was a trend toward decreasing aqueous humor flow rate (-15%; P = 0.08). No treatment changes were seen in uveoscleral outflow rate. CONCLUSIONS Once-daily dosing of netarsudil ophthalmic solution 0.02% lowered IOP through increasing trabecular outflow facility and reducing EVP. This suggests a combination of mechanisms that affect both the proximal and distal outflow pathways.
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Affiliation(s)
- Arash Kazemi
- 1 Department of Ophthalmology, Mayo Clinic , Rochester, Minnesota
| | - Jay W McLaren
- 1 Department of Ophthalmology, Mayo Clinic , Rochester, Minnesota
| | - Casey C Kopczynski
- 2 Aerie Pharmaceuticals, Inc. , Bedminster, New Jersey.,3 Aerie Pharmaceuticals, Inc. , Durham, North Carolina
| | - Theresa G Heah
- 2 Aerie Pharmaceuticals, Inc. , Bedminster, New Jersey.,3 Aerie Pharmaceuticals, Inc. , Durham, North Carolina
| | - Gary D Novack
- 4 Departments of Ophthalmology and Pharmacology, University of California , Davis, California.,5 PharmaLogic Development, Inc. , San Rafael, California
| | - Arthur J Sit
- 1 Department of Ophthalmology, Mayo Clinic , Rochester, Minnesota
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39
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Smith DW, Gardiner BS. Estimating outflow facility through pressure dependent pathways of the human eye. PLoS One 2017; 12:e0188769. [PMID: 29261696 PMCID: PMC5738051 DOI: 10.1371/journal.pone.0188769] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 11/13/2017] [Indexed: 01/06/2023] Open
Abstract
We develop and test a new theory for pressure dependent outflow from the eye. The theory comprises three main parameters: (i) a constant hydraulic conductivity, (ii) an exponential decay constant and (iii) a no-flow intraocular pressure, from which the total pressure dependent outflow, average outflow facilities and local outflow facilities for the whole eye may be evaluated. We use a new notation to specify precisely the meaning of model parameters and so model outputs. Drawing on a range of published data, we apply the theory to animal eyes, enucleated eyes and in vivo human eyes, and demonstrate how to evaluate model parameters. It is shown that the theory can fit high quality experimental data remarkably well. The new theory predicts that outflow facilities and total pressure dependent outflow for the whole eye are more than twice as large as estimates based on the Goldman equation and fluorometric analysis of anterior aqueous outflow. It appears likely that this discrepancy can be largely explained by pseudofacility and aqueous flow through the retinal pigmented epithelium, while any residual discrepancy may be due to pathological processes in aged eyes. The model predicts that if the hydraulic conductivity is too small, or the exponential decay constant is too large, then intraocular eye pressure may become unstable when subjected to normal circadian changes in aqueous production. The model also predicts relationships between variables that may be helpful when planning future experiments, and the model generates many novel testable hypotheses. With additional research, the analysis described here may find application in the differential diagnosis, prognosis and monitoring of glaucoma.
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Affiliation(s)
- David W. Smith
- Faculty of Engineering and Mathematical Sciences, The University of Western Australia, Perth, Australia
| | - Bruce S. Gardiner
- School of Engineering and Information Technology, Murdoch University, Murdoch, Western Australia, Australia
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40
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Zhang LF, Hargens AR. Spaceflight-Induced Intracranial Hypertension and Visual Impairment: Pathophysiology and Countermeasures. Physiol Rev 2017; 98:59-87. [PMID: 29167331 DOI: 10.1152/physrev.00017.2016] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 05/25/2017] [Accepted: 05/26/2017] [Indexed: 12/21/2022] Open
Abstract
Visual impairment intracranial pressure (VIIP) syndrome is considered an unexplained major risk for future long-duration spaceflight. NASA recently redefined this syndrome as Spaceflight-Associated Neuro-ocular Syndrome (SANS). Evidence thus reviewed supports that chronic, mildly elevated intracranial pressure (ICP) in space (as opposed to more variable ICP with posture and activity on Earth) is largely accounted for by loss of hydrostatic pressures and altered hemodynamics in the intracranial circulation and the cerebrospinal fluid system. In space, an elevated pressure gradient across the lamina cribrosa, caused by a chronic but mildly elevated ICP, likely elicits adaptations of multiple structures and fluid systems in the eye which manifest themselves as the VIIP syndrome. A chronic mismatch between ICP and intraocular pressure (IOP) in space may acclimate the optic nerve head, lamina cribrosa, and optic nerve subarachnoid space to a condition that is maladaptive to Earth, all contributing to the pathogenesis of space VIIP syndrome. Relevant findings help to evaluate whether artificial gravity is an appropriate countermeasure to prevent this seemingly adverse effect of long-duration spaceflight.
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Affiliation(s)
- Li-Fan Zhang
- Department of Aerospace Physiology, Fourth Military Medical University, Xi'an, China; and Department of Orthopaedic Surgery, University of California, San Diego, California
| | - Alan R Hargens
- Department of Aerospace Physiology, Fourth Military Medical University, Xi'an, China; and Department of Orthopaedic Surgery, University of California, San Diego, California
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41
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Huang AS, Francis BA, Weinreb RN. Structural and functional imaging of aqueous humour outflow: a review. Clin Exp Ophthalmol 2017; 46:158-168. [PMID: 28898516 DOI: 10.1111/ceo.13064] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 09/06/2017] [Indexed: 01/15/2023]
Abstract
Maintaining healthy aqueous humour outflow (AHO) is important for intraocular cellular health and stable vision. Impairment of AHO can lead to increased intraocular pressure, optic nerve damage and concomitant glaucoma. An improved understanding of AHO will lead to improved glaucoma surgeries that enhance native AHO as well as facilitate the development of AHO-targeted pharmaceuticals. Recent AHO imaging has evolved to live human assessment and has focused on the structural evaluation of AHO pathways and the functional documentation of fluid flow. Structural AHO evaluation is predominantly driven by optical coherence tomography, and functional evaluation of flow is performed using various methods, including aqueous angiography. Advances in structural and functional evaluation of AHO are reviewed with discussion of strengths, weaknesses and potential future directions.
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Affiliation(s)
- Alex S Huang
- Doheny Eye Institute, Los Angeles, California, USA.,Doheny Eye Centers, Department of Ophthalmology, David Geffen School of Medicine at University of California, Los Angeles, California, USA
| | - Brian A Francis
- Doheny Eye Institute, Los Angeles, California, USA.,Doheny Eye Centers, Department of Ophthalmology, David Geffen School of Medicine at University of California, Los Angeles, California, USA
| | - Robert N Weinreb
- Shiley Eye Institute and Hamilton Glaucoma Center, Department of Ophthalmology, University of California, San Diego, California, USA
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42
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Loewen RT, Brown EN, Scott G, Parikh H, Schuman JS, Loewen NA. Quantification of Focal Outflow Enhancement Using Differential Canalograms. Invest Ophthalmol Vis Sci 2017; 57:2831-8. [PMID: 27227352 PMCID: PMC5113980 DOI: 10.1167/iovs.16-19541] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To quantify regional changes of conventional outflow caused by ab interno trabeculectomy (AIT). Methods Gonioscopic, plasma-mediated AIT was established in enucleated pig eyes. We developed a program to automatically quantify outflow changes (R, package eye-canalogram, github.com) using a fluorescent tracer reperfusion technique. Trabecular meshwork (TM) ablation was demonstrated with fluorescent spheres in six eyes before formal outflow quantification with two-dye reperfusion canalograms in six additional eyes. Eyes were perfused with a central, intracameral needle at 15 mm Hg. Canalograms and histology were correlated for each eye. Results The pig eye provided a model with high similarity to AIT in human patients. Histology indicated ablation of TM and unroofing of most Schlemm's canal segments. Spheres highlighted additional circumferential and radial outflow beyond the immediate area of ablation. Differential canalograms showed that AIT caused an increase of outflow of 17 ± 5-fold inferonasally, 14 ± 3-fold superonasally, and also an increase in the opposite quadrants with a 2 ± 1-fold increase superotemporally, and 3 ± 3 inferotemporally. Perilimbal specific flow image analysis showed an accelerated nasal filling with an additional perilimbal flow direction into adjacent quadrants. Conclusions A quantitative, differential canalography technique was developed that allows us to quantify supraphysiological outflow enhancement by AIT.
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Affiliation(s)
- Ralitsa T Loewen
- Department of Ophthalmology University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Eric N Brown
- Department of Ophthalmology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Gordon Scott
- Department of Ophthalmology University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
| | - Hardik Parikh
- Department of Ophthalmology University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States 3School of Medicine, Rutgers State University of New Jersey, New Brunswick, New Jersey, United States
| | - Joel S Schuman
- Department of Ophthalmology University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States 4School of Medicine, New York University, New York, New York, United States
| | - Nils A Loewen
- Department of Ophthalmology University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States
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43
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Guo T, Sampathkumar S, Fan S, Morris N, Wang F, Toris CB. Aqueous humour dynamics and biometrics in the ageing Chinese eye. Br J Ophthalmol 2017; 101:1290-1296. [DOI: 10.1136/bjophthalmol-2016-309883] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 04/20/2017] [Accepted: 05/03/2017] [Indexed: 11/04/2022]
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44
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Johnson M, McLaren JW, Overby DR. Unconventional aqueous humor outflow: A review. Exp Eye Res 2017; 158:94-111. [PMID: 26850315 PMCID: PMC4970980 DOI: 10.1016/j.exer.2016.01.017] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 01/04/2016] [Accepted: 01/26/2016] [Indexed: 11/17/2022]
Abstract
Aqueous humor flows out of the eye primarily through the conventional outflow pathway that includes the trabecular meshwork and Schlemm's canal. However, a fraction of aqueous humor passes through an alternative or 'unconventional' route that includes the ciliary muscle, supraciliary and suprachoroidal spaces. From there, unconventional outflow may drain through two pathways: a uveoscleral pathway where aqueous drains across the sclera to be resorbed by orbital vessels, and a uveovortex pathway where aqueous humor enters the choroid to drain through the vortex veins. We review the anatomy, physiology and pharmacology of these pathways. We also discuss methods to determine unconventional outflow rate, including direct techniques that use radioactive or fluorescent tracers recovered from tissues in the unconventional pathway and indirect methods that estimate unconventional outflow based on total outflow over a range of pressures. Indirect methods are subject to a number of assumptions and generally give poor agreement with tracer measurements. We review the variety of animal models that have been used to study conventional and unconventional outflow. The mouse appears to be a promising model because it captures several aspects of conventional and unconventional outflow dynamics common to humans, although questions remain regarding the magnitude of unconventional outflow in mice. Finally, we review future directions. There is a clear need to develop improved methods for measuring unconventional outflow in both animals and humans.
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Affiliation(s)
- Mark Johnson
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA; Department of Mechanical Engineering, Northwestern University, Evanston, IL, USA; Department of Ophthalmology, Northwestern University, Chicago, IL, USA.
| | - Jay W McLaren
- Department of Ophthalmology, Mayo Clinic, Rochester, MN, USA
| | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London, England, UK
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45
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Fallano K, Bussel I, Kagemann L, Lathrop KL, Loewen N. Training strategies and outcomes of ab interno trabeculectomy with the trabectome. F1000Res 2017; 6:67. [PMID: 28529695 PMCID: PMC5428488 DOI: 10.12688/f1000research.10236.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/20/2017] [Indexed: 11/05/2023] Open
Abstract
Plasma-mediated ab interno trabeculectomy with the trabectome was first approved by the US Food and Drug Administration in 2004 for use in adult and pediatric glaucomas. Since then, increased clinical experience and updated outcome data have led to its expanded use, including a range of glaucomas and angle presentations, previously deemed to be relatively contraindicated. The main benefits are a high degree of safety, ease, and speed compared to traditional filtering surgery and tube shunts. The increasing burden of glaucoma and expanding life expectancy has resulted in demand for well-trained surgeons. In this article, we discuss the results of trabectome surgery in standard and nonstandard indications. We present training strategies of the surgical technique that include a pig eye model, and visualization exercises that can be performed before and at the conclusion of standard cataract surgery in patients who do not have glaucoma. We detail the mechanism of enhancing the conventional outflow pathway and describe methods of visualization and function testing.
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Affiliation(s)
- Katherine Fallano
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Igor Bussel
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Larry Kagemann
- Food and Drug Administration, Silver Springs, MS, USA
- Department of Ophthalmology, New York University School of Medicine, New York, NY, USA
| | - Kira L. Lathrop
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Nils Loewen
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Fallano K, Bussel I, Kagemann L, Lathrop KL, Loewen N. Training strategies and outcomes of ab interno trabeculectomy with the trabectome. F1000Res 2017; 6:67. [PMID: 28529695 PMCID: PMC5428488 DOI: 10.12688/f1000research.10236.2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/26/2017] [Indexed: 01/15/2023] Open
Abstract
Plasma-mediated ab interno trabeculectomy with the trabectome was first approved by the US Food and Drug Administration in 2004 for use in adult and pediatric glaucomas. Since then, increased clinical experience and updated outcome data have led to its expanded use, including a range of glaucomas and angle presentations, previously deemed to be relatively contraindicated. The main benefits are a high degree of safety, ease, and speed compared to traditional filtering surgery and tube shunts. The increasing burden of glaucoma and expanding life expectancy has resulted in demand for well-trained surgeons. In this article, we discuss the results of trabectome surgery in standard and nonstandard indications. We present training strategies of the surgical technique that include a pig eye model, and visualization exercises that can be performed before and at the conclusion of standard cataract surgery in patients who do not have glaucoma. We detail the mechanism of enhancing the conventional outflow pathway and describe methods of visualization and function testing.
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Affiliation(s)
- Katherine Fallano
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Igor Bussel
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Larry Kagemann
- Food and Drug Administration, Silver Springs, MS, USA
- Department of Ophthalmology, New York University School of Medicine, New York, NY, USA
| | - Kira L. Lathrop
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Nils Loewen
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Fini ME, Schwartz SG, Gao X, Jeong S, Patel N, Itakura T, Price MO, Price FW, Varma R, Stamer WD. Steroid-induced ocular hypertension/glaucoma: Focus on pharmacogenomics and implications for precision medicine. Prog Retin Eye Res 2017; 56:58-83. [PMID: 27666015 PMCID: PMC5237612 DOI: 10.1016/j.preteyeres.2016.09.003] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 09/17/2016] [Accepted: 09/19/2016] [Indexed: 02/06/2023]
Abstract
Elevation of intraocular pressure (IOP) due to therapeutic use of glucocorticoids is called steroid-induced ocular hypertension (SIOH); this can lead to steroid-induced glaucoma (SIG). Glucocorticoids initiate signaling cascades ultimately affecting expression of hundreds of genes; this provides the potential for a highly personalized pharmacological response. Studies attempting to define genetic risk factors were undertaken early in the history of glucocorticoid use, however scientific tools available at that time were limited and progress stalled. In contrast, significant advances were made over the ensuing years in defining disease pathophysiology. As the genomics age emerged, it appeared the time was right to renew investigation into genetics. Pharmacogenomics is an unbiased discovery approach, not requiring an underlying hypothesis, and provides a way to pinpoint clinically significant genes and pathways that could not have been discovered any other way. Results of the first genome-wide association study to identify polymorphisms associated with SIOH, and follow-up on two novel genes linked to the disorder, GPR158 and HCG22, is discussed in the second half of the article. However, knowledge of genetic variants determining response to steroids in the eye also has value in its own right as a predictive and diagnostic tool. This article concludes with a discussion of how the Precision Medicine Initiative®, announced by U.S. President Obama in his 2015 State of the Union address, is beginning to touch the practice of ophthalmology. It is argued that SIOH/SIG may provide one of the next opportunities for effective application of precision medicine.
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Affiliation(s)
- M Elizabeth Fini
- USC Institute for Genetic Medicine and Department of Cell & Neurobiology, Keck School of Medicine of USC, University of Southern California, 2250 Alcatraz St., Suite 240, Los Angeles, CA, 90089, USA.
| | - Stephen G Schwartz
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 3880 Tamiami Trail North, Naples, FL, 34103, USA.
| | - Xiaoyi Gao
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1905 W Taylor St., Suite 235, Chicago, IL, 60612, USA.
| | - Shinwu Jeong
- USC Institute for Genetic Medicine, USC Roski Eye Institute and Department of Ophthalmology, Keck School of Medicine of USC, University of Southern California, 2250 Alcatraz St., Suite 240, Los Angeles, CA, 90089, USA.
| | - Nitin Patel
- USC Institute for Genetic Medicine, Keck School of Medicine of USC, University of Southern California, 2250 Alcatraz St., Suite 240, Los Angeles, CA, 90089, USA.
| | - Tatsuo Itakura
- USC Institute for Genetic Medicine, Keck School of Medicine of USC, University of Southern California, 2250 Alcatraz St., Suite 240, Los Angeles, CA, 90089, USA.
| | - Marianne O Price
- Cornea Research Foundation of America, 9002 North Meridian Street, Indianapolis, IN, 46260, USA.
| | - Francis W Price
- Price Vision Group, 9002 North Meridian Street, Indianapolis, IN, 46260, USA.
| | - Rohit Varma
- Office of the Dean, USC Roski Eye Institute and Department of Ophthalmology, Keck School of Medicine of USC, University of Southern California, 1975 Zonal Ave., KAM 500, Los Angeles, CA, 90089, USA.
| | - W Daniel Stamer
- Department of Ophthalmology and Department of Biomedical Engineering, Duke University, AERI Room 4008, 2351 Erwin Rd, Durham, NC, 27705, USA.
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48
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Huang AS, Minasyan L, Weinreb RN. Glaucoma-Intraocular Pressure Reduction. Handb Exp Pharmacol 2016; 242:181-207. [PMID: 27812895 DOI: 10.1007/164_2016_24] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Medical treatment is a mainstay for the management of glaucoma (Realini 2011; Marquis and Whitson 2005; Hoyng and van Beek 2000). Intraocular pressure (IOP) lowering has been long recognized as and still represents the primary and most widely employed treatment to prevent glaucomatous vision loss (Musch et al. 2011; Leske et al. 2003; The Advanced Glaucoma Intervention Study (AGIS) 2000). Soon after the recognition that "tension" or IOP was related to glaucoma, pharmacological agents were introduced in the mid-1800s, first with the calabar bean (Realini 2011; Proudfoot 2006). Since then, an explosion of pharmacological agents targeting numerous intracellular and molecular signaling pathways has resulted in a plethora of drugs to lower IOP and treat glaucoma. Aqueous humor dynamics provides the basis for understanding each of these medical therapies.
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Affiliation(s)
- Alex S Huang
- Doheny Eye Centers, Doheny and Stein Eye Institutes, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Lilit Minasyan
- Doheny Eye Centers, Doheny and Stein Eye Institutes, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Robert N Weinreb
- Hamilton Glaucoma Center, Shiley Eye Institute, UCSD, La Jolla, CA, USA.
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Kanadani FN, Moreira T, Campos LF, Vianello MP, Corradi J, Dorairaj SK, Freitas A, Ritch R. A New Provocative Test for Glaucoma. J Curr Glaucoma Pract 2016; 10:1-3. [PMID: 27231412 PMCID: PMC4875727 DOI: 10.5005/jp-journals-10008-1194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 12/23/2015] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To compare the effects of the water-drinking test (WDT) with the 30° inverted body position test on intraocular pressure (IOP) in normal patients, suspected glaucoma patients and glaucoma patients. MATERIALS AND METHODS Based on clinical evaluation of the optic disk, IOP, and standard achromatic perimetry (SAP) of 71 eyes, 18 were "normal" (normal SAP and optic disk evaluation, and IOP < 21 mm Hg), 30 were "glaucoma suspect" (GS; normal SAP, cup/disk (C/D) ratio > 0.5 or asymmetry > 0.2 and/or ocular hypertension), and 31 had "early glaucoma" (MD < -6 dB, glaucomatous optic neuropathy). Standard achromatic perimetry was performed with the Octopus 3.1.1 Dynamic 24-2 program. Patients fasted before the WDT, and four measurements were performed at basal, 15', 30, and 45' after drinking 1 liter of water (WDT) in 5 minutes. In the 30° inverted position, IOP measurement with Perkins applanation tonometer was taken after 5 minutes lying down. RESULTS There was a statistical difference in all groups between the basal IOP and peak IOP during the WDT (p < 0.001) and in the inverted position IOP (p < 0.001). Controls (p = 0.50), suspects (p = 0.41) and glaucoma patients (p = 1.0) did not exhibit a difference between WDT-IOP and inverted position IOP. CONCLUSION The 30° inverted position test was as efficient as WDT in detecting peak IOP. This new provocative test is easier, faster and more comfortable for both patients and doctors. How to cite this article: Kanadani FN, Moreira TCA, Campos LF, Vianello MP, Corradi J, Dorairaj SK, Freitas ALA, Ritch R. A New Provocative Test for Glaucoma. J Curr Glaucoma Pract 2016;10(1): 1-3.
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Affiliation(s)
- Fabio N Kanadani
- Chief, Department of Ophthalmology, Medical Science Ophthalmology Institute, Belo Horizonte, Brazil
| | - Tca Moreira
- Assistant Professor, Department of Retina, Medical Science Ophthalmology Institute, Belo Horizonte, Brazil
| | - L F Campos
- Assistant Professor, Department of Glaucoma, Medical Science Ophthalmology Institute, Belo Horizonte, Brazil
| | - M P Vianello
- Assistant Professor, Department of Glaucoma, Medical Science Ophthalmology Institute, Belo Horizonte, Brazil
| | - J Corradi
- Assistant Professor, Department of Glaucoma, Medical Science Ophthalmology Institute, Belo Horizonte, Brazil
| | - S K Dorairaj
- Assistant Professor, Department of Ophthalmology/Glaucoma, Mayo Clinic Jacksonville, Florida, USA
| | - Ala Freitas
- Assistant Professor, Department of Glaucoma, Medical Science Ophthalmology Institute, Belo Horizonte, Brazil
| | - R Ritch
- Assistant Professor, Department of Ophthalmology/Glaucoma, Mayo Clinic Jacksonville, Florida, USA
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Dang Y, Roy P, Bussel II, Loewen RT, Parikh H, Loewen NA. Combined analysis of trabectome and phaco-trabectome outcomes by glaucoma severity. F1000Res 2016; 5:762. [PMID: 27239278 PMCID: PMC4870993 DOI: 10.12688/f1000research.8448.2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/20/2016] [Indexed: 11/20/2022] Open
Abstract
Prior glaucoma severity staging systems were mostly concerned with visual field function and retinal nerve fiber layer, but did not include intraocular pressure or medications to capture resistance to treatment. We recently introduced a simple index that combines pressure, medications, and visual field damage and applied it to stratify outcomes of trabectome surgery. In the analysis presented here, we combined data of trabectome alone and trabectome with same session cataract surgery to increase testing power and chances of effect discovery. This microincisional glaucoma surgery removes the primary resistance to outflow in glaucoma, the trabecular meshwork, and has been mostly used in mild glaucoma. Traditional glaucoma surgeries have a relatively high complication rate and have been reserved for more advanced disease stages. In the analysis presented here we include our data of trabectome combined with cataract surgery. This is a common practice pattern as both occur in the same age group with increasing frequency. For patients in higher glaucoma index (GI) groups, the intraocular pressure (IOP) reduction was 2.34+/-0.19 mmHg more than those in a GI group one level lower while holding everything else constant. Those who had undergone trabectome combined with phacoemulsification had an IOP reduction that was 1.29+/-0.39 mmHg less compared to those with trabectome alone. No statistically significant difference was found between genders and age groups while holding everything else constant. Hispanics had a 3.81+/-1.08 mmHg greater IOP reduction. Pseudoexfoliation and steroid glaucoma patients had an IOP reduction that was greater by 2.91+/-0.56 and 3.86+/-0.81 mmHg, respectively, than those with primary open angle glaucoma. These results suggest a role for trabectome-mediated ab interno trabeculectomy beyond mild forms of glaucoma. Additionally, the multifactorial glaucoma index demonstrates a role in staging patients when comparing glaucoma surgical modalities.
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Affiliation(s)
- Yalong Dang
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, USA
| | - Pritha Roy
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, USA
| | - Igor I Bussel
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, USA
| | - Ralitsa T Loewen
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, USA
| | - Hardik Parikh
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, USA
| | - Nils A Loewen
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, USA
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