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Raiskup F, Herber R, Lenk J, Pillunat LE, Spoerl E. Crosslinking with UV-A and riboflavin in progressive keratoconus: From laboratory to clinical practice - Developments over 25 years. Prog Retin Eye Res 2024; 102:101276. [PMID: 38830532 DOI: 10.1016/j.preteyeres.2024.101276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/30/2024] [Accepted: 05/31/2024] [Indexed: 06/05/2024]
Abstract
Changes in the biomechanical and biochemical properties of the human cornea play an important role in the pathogenesis of ectatic diseases. A number of conditions in primarily acquired (keratoconus or pellucid marginal degeneration) or secondarily induced (iatrogenic keratectasia after refractive laser surgeries) ectatic disorders lead to decreased biomechanical stability. Corneal collagen cross-linking (CXL) represents a technique to slow or even halt the progression of ectatic pathologies. In this procedure, riboflavin is applied in combination with ultraviolet A radiation. This interaction induces the production of reactive oxygen species, which leads to the formation of additional covalent bonds between collagen molecules and subsequent biomechanical corneal strengthening. This procedure is so far the only method that partially interferes etiopathogenetically in the treatment of ectatic diseases that slows or stops the process of corneal destabilization, otherwise leading to the need for corneal transplantation. Besides, CXL process increases markedly resistance of collagenous matrix against digesting enzymes supporting its use in the treatment of corneal ulcers. Since the discovery of this therapeutic procedure and the first laboratory experiments, which confirmed the validity of this method, and the first clinical studies that proved the effectiveness and safety of the technique, it has been spread and adopted worldwide, even with further modifications. Making use of the Bunsen-Roscoe photochemical law it was possible to shorten the duration of this procedure in accelerated CXL and thus improve the clinical workflow and patient compliance while maintaining the efficacy and safety of the procedure. The indication spectrum of CXL can be further expanded by combining it with other vision-enhancing procedures such as individualized topographically-guided excimer ablation. Complementing both techniques will allow a patient with a biomechanically stable cornea to regularize it and improve visual acuity without the need for tissue transplantation, leading to a long-term improvement in quality of life.
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Affiliation(s)
- Frederik Raiskup
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany.
| | - Robert Herber
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Janine Lenk
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Lutz E Pillunat
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
| | - Eberhard Spoerl
- Department of Ophthalmology, University Hospital Carl Gustav Carus, TU Dresden, Fetscherstrasse 74, 01307, Dresden, Germany
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Al Bdour M, Sabbagh HM, Jammal HM. Multi-modal imaging for the detection of early keratoconus: a narrative review. EYE AND VISION (LONDON, ENGLAND) 2024; 11:18. [PMID: 38730479 PMCID: PMC11088107 DOI: 10.1186/s40662-024-00386-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 04/21/2024] [Indexed: 05/12/2024]
Abstract
Keratoconus is a common progressive corneal disorder that can be associated with significant ocular morbidity. Various corneal imaging techniques have been used for the diagnosis of established cases. However, in the early stages of the disease, which include subclinical keratoconus and forme fruste keratoconus, detection of such cases can be challenging. The importance of detecting such cases is very important because early intervention can halt disease progression, improve visual outcomes and prevent postrefractive surgery ectasia associated with performing corneal refractive procedures in such patients. This narrative review aimed to examine several established and evolving imaging techniques for the detection of early cases of keratoconus. The utilization of combinations of these techniques may further increase their diagnostic ability.
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Affiliation(s)
- Muawyah Al Bdour
- Department of Ophthalmology, School of Medicine, The University of Jordan, Amman, Jordan
| | - Hashem M Sabbagh
- The National Center for Diabetes Endocrinology and Genetics (NCDEG), Amman, Jordan
| | - Hisham M Jammal
- Department of Ophthalmology, Faculty of Medicine, Jordan University of Science and Technology, PO Box 3030, Irbid, 22110, Jordan.
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Hammelef E, Rapuano CJ, Benedetto DA, Syed ZA, Myers JS, Razeghinejad MR, Silver FH, Pulido JS. New forays into measurement of ocular biomechanics. Curr Opin Ophthalmol 2024; 35:225-231. [PMID: 38484223 DOI: 10.1097/icu.0000000000001032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2024]
Abstract
PURPOSE OF REVIEW The field of corneal biomechanics has rapidly progressed in recent years, reflecting technological advances and an increased understanding of the clinical significance of measuring these properties. This review will evaluate in-vivo biomechanical properties obtained by current technologies and compare them regarding their relevance to established biomechanical properties obtained by gold-standard ex-vivo techniques normally conducted on elastic materials. RECENT FINDINGS Several new technologies have appeared in recent years, including vibrational optical coherence tomography (VOCT) and the corneal indentation device (CID). These techniques provide promising new opportunities for minimally invasive and accurate measurements of corneal viscoelastic properties. SUMMARY Alterations in corneal biomechanics are known to occur in several corneal degenerative diseases and after refractive surgical procedures. The measurement of corneal biomechanical properties has the capability to diagnose early disease and monitor corneal disease progression. Several new technologies have emerged in recent years, allowing for more accurate and less invasive measurements of corneal biomechanical properties, most notably the elastic modulus.
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Affiliation(s)
- Emma Hammelef
- Sidney Kimmel Medical College at Thomas Jefferson University at Thomas Jefferson University
| | - Christopher J Rapuano
- Wills Eye Hospital, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Dominick A Benedetto
- Center for Advanced Eye Care, Vero Beach, Florida
- OptoVibronex, LLC, Bethlehem, Pennsylvania
| | - Zeba A Syed
- Wills Eye Hospital, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Jonathan S Myers
- Wills Eye Hospital, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - M Reza Razeghinejad
- Wills Eye Hospital, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Fred H Silver
- OptoVibronex, LLC, Bethlehem, Pennsylvania
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Jose S Pulido
- Wills Eye Hospital, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania
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Sagaltici DA, Kurt E, Seymenoglu RG, Mayali H, Hekimsoy Z. The Effect of Diabetic Retinopathy and Blood Glucose Regulation on Corneal Biomechanical Parameters. Curr Eye Res 2024:1-6. [PMID: 38587365 DOI: 10.1080/02713683.2024.2338219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 03/28/2024] [Indexed: 04/09/2024]
Abstract
PURPOSE The aim of this study was to evaluate the effects of different stages of diabetic retinopathy (DR) and metabolic control of blood glucose levels on corneal biomechanical parameters. METHODS Diabetic patients were categorized into three groups: no DR group, nonproliferative DR (NPDR) group, and proliferative DR (PDR) group. Of the 141 eyes examined, 40 belonged to the control group, 34 to no DR group, 34 to NPDR group, and 33 to PDR group. Using an Ocular Response Analyzer to measure corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated IOP (IOPcc). IOP was assessed using a Tono-Pen, while central corneal thickness (CCT) was determined using an ultrasonic pachymeter. HbA1c levels were also recorded. We conducted comparisons among these groups across biomechanical parameters and IOP (tonopen), and CCT, while also investigating the impact of HbA1c levels on these parameters. RESULTS Among any groups show a statistically significant difference in CCT, IOP (tonopen), CH, CRF, IOPg, and IOPcc. In diabetic patients, CRF, CTT, and IOPg values were significantly higher in those with HbA1c levels ≥ 7 mg/dl than in those with HbA1c levels < 7 mg/dl (p = 0.009, p = 0.013, p = 0.038), respectively, while there was no statistically significant difference in IOPcc, CH, and IOP (tonopen). Linear regression analysis showed that CH was positively associated with CCT (p < 0.001) and negatively associated with IOPcc (p < 0.001), while CRF was positively associated with CCT (p < 0.001), HbA1c (p < 0.05), and negatively associated with diagnosis of DR (p < 0.05). CONCLUSION This study underscores the influence of metabolic control, as reflected by HbA1c levels, on corneal biomechanical parameters in diabetic patients, emphasizing the importance of monitoring and managing glycemic control in this population.
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Affiliation(s)
- Duygu Akbulut Sagaltici
- University of Health Sciences, Bagcilar Training and Research Hospital, Department of Ophthalmology, Istanbul, Turkey
| | - Emin Kurt
- Department of Ophthalmology, Manisa Celal Bayar University, Manisa, Turkey
| | | | - Huseyin Mayali
- Department of Ophthalmology, Manisa Celal Bayar University, Manisa, Turkey
| | - Zeliha Hekimsoy
- Department of Endocrinology and Metabolism, Manisa Celal Bayar University, Manisa, Turkey
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Dhiman R, Singh D, Vanathi M, Tandon R, Mahalingam K. Biomechanical properties of cornea and ocular aberrations in myopic eyes. Indian J Ophthalmol 2024; 72:538-543. [PMID: 38099386 PMCID: PMC11149510 DOI: 10.4103/ijo.ijo_1627_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/06/2023] [Indexed: 12/19/2023] Open
Abstract
PURPOSE To study the correlation of corneal topography, corneal biomechanical properties, and ocular aberrations with the magnitude of refractive error in myopic eyes. METHODS All myopic patients attending the clinic for refractive surgery were recruited. Data recorded included visual acuity, axial length (AL), central corneal thickness (CCT), manifest refraction spherical equivalent (MRSE), topography (Pentacam - Oculus), corneal biomechanical factors [ocular response analyzer (ORA)], and optical aberrations (iTrace). They were further categorized into group 1 (suitable for femto-LASIK) and group 2 (unsuitable for femto-LASIK). RESULTS Sixty eyes (30 myopes) of mean age 22.78 ± 2.71 years were enrolled. A negative correlation of refractive error was noted with AL (ρ = -0.9; P < 0.001), total aberrations (ρ = 0.53; P < 0.001), and lower-order aberrations (LOA) (ρ = 0.54; P < 0.001). A strongly positive correlation was noted between CCT and corneal hysteresis (CH) (ρ = 0.63; P < 0.001), CCT and CRF (ρ = 0.56; P < 0.001), CH and corneal resistance factor (CRF) (ρ = 0.83; P < 0.001), and Goldmann equivalent intraocular pressure (IOPg) and corneal compensated intraocular pressure (IOPcc) (ρ = 0.78; P < 0.001). An increase in higher-order aberrations (HOAs) as well as lower-order aberrations (LOAs) was noted with increasing sim-K [HOA (r = 0.73, P = 0.001); LOA (r = 0.601, P = 0.014)] and increasing CRF [HOA (r = 0.5, P = 0.006); LOA (r = 0.732, P = 0.001)] in group 2. The amount of refractive error, axial length, central corneal thickness, and sim-K were significantly different in the two groups. CONCLUSION Increasing degree of myopia is associated with an increase in axial length, total aberrations, and lower-order aberrations. Corneal biomechanical parameters have a strong correlation with each other. Lower corneal biomechanics are noted in high myopes as they have weaker and thinner corneas. Corneal biomechanics and ocular aberrations do not differ significantly between cases suitable for femto-LASIK and cases unsuitable for femto-LASIK.
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Affiliation(s)
- Rebika Dhiman
- Dr. R. P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
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Erb C, Erb C, Kazakov A, Umetalieva M, Weisser B. Influence of Diabetes Mellitus on Glaucoma-Relevant Examination Results in Primary Open-Angle Glaucoma. Klin Monbl Augenheilkd 2024; 241:177-185. [PMID: 37643738 DOI: 10.1055/a-2105-0756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Primary open-angle glaucoma (POAG) is no longer considered an isolated eye pressure-dependent optic neuropathy, but a neurodegenerative disease in which oxidative stress and neuroinflammation are prominent. These processes may be exacerbated by additional systemic diseases. The most common are arterial hypertension, dyslipidemia, and diabetes mellitus. Using diabetes mellitus as an example, it will be shown how far-reaching the influence of such a systemic disease can be on both the functional and the structural diagnostic methods for POAG. This knowledge is essential, since these interferences can lead to misinterpretations of POAG, which can also affect therapeutic decisions.
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Affiliation(s)
- Carl Erb
- Augenklinik am Wittenbergplatz, Berlin, Deutschland
| | | | - Avaz Kazakov
- Department of External Relations and Development, Salymbekov University, Bishkek, Kyrgyzstan
| | - Maana Umetalieva
- Medical Faculty of Medicine, Salymbekov University, Bishkek, Kyrgyzstan
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Li DL, Liu MX, Yin ZJ, Li YZ, Ma R, Zheng YJ, Qin Y, Liang G, Pan CW. Refractive associations with corneal biomechanical properties among young adults: a population-based Corvis ST study. Graefes Arch Clin Exp Ophthalmol 2024; 262:121-132. [PMID: 37401934 DOI: 10.1007/s00417-023-06164-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 06/11/2023] [Accepted: 06/28/2023] [Indexed: 07/05/2023] Open
Abstract
PURPOSE To assess the associations of corneal biomechanical properties as measured by the Corvis ST with refractive errors and ocular biometry in an unselected sample of young adults. METHODS A total of 1645 healthy university students underwent corneal biomechanical parameters measurement by the Corvis ST. The refractive status of the participants was measured using an autorefractor without cycloplegia. Ocular biometric parameters were measured using the IOL Master. RESULTS After adjusting for the effect of age, sex, biomechanical-corrected intraocular pressure and central corneal thickness, axial length was significantly associated with A1 velocity (A1v, β = -10.47), A2 velocity (A2v, β = 4.66), A2 deflection amplitude (A2DeflA, β = -6.02), HC deflection amplitude (HC-DeflA, β = 5.95), HC peak distance (HC-PD, β = 2.57), deformation amplitude ratio max (DA Rmax, β = -0.36), Ambrósio's relational thickness to the horizontal profile (ARTh, β = 0.002). For axial length / corneal radius ratio, only A1v (β = -2.01), A1 deflection amplitude (A1DeflA, β = 2.30), HC-DeflA (β = 1.49), HC-PD (β = -0.21), DA Rmax (β = 0.07), stress-strain index (SSI, β = -0.29), ARTh (β < 0.001) were significant associates. A1v (β = 23.18), HC-DeflA (β = -15.36), HC-PD (β = 1.27), DA Rmax (β = -0.66), SSI (β = 3.53), ARTh (β = -0.02) were significantly associated with spherical equivalent. CONCLUSION Myopic eyes were more likely to have more deformable corneas and corneas in high myopia were easier to deform and were even softer compared with those in the mild/moderate myopia.
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Affiliation(s)
- Dan-Lin Li
- School of Public Health, Medical College of Soochow University, 199 Ren Ai Road, Suzhou, 215123, China
| | - Min-Xin Liu
- School of Public Health, Medical College of Soochow University, 199 Ren Ai Road, Suzhou, 215123, China
| | - Zhi-Jian Yin
- Department of Ophthalmology, the First Affiliated Hospital of Dali University, Dali, China
| | - Yue-Zu Li
- Department of Ophthalmology, the Affiliated Hospital of Yunnan University, 176 Qing Nian Road, Kunming, 650021, China
- Department of Ophthalmology, the Second People's Hospital of Yunnan Province, Kunming, China
| | - Rong Ma
- Department of Ophthalmology, the Affiliated Hospital of Yunnan University, 176 Qing Nian Road, Kunming, 650021, China
- Department of Ophthalmology, the Second People's Hospital of Yunnan Province, Kunming, China
| | - Ya-Jie Zheng
- Department of Ophthalmology, the Affiliated Hospital of Yunnan University, 176 Qing Nian Road, Kunming, 650021, China
- Department of Ophthalmology, the Second People's Hospital of Yunnan Province, Kunming, China
| | - Yu Qin
- Department of Ophthalmology, the Affiliated Hospital of Yunnan University, 176 Qing Nian Road, Kunming, 650021, China
- Department of Ophthalmology, the Second People's Hospital of Yunnan Province, Kunming, China
| | - Gang Liang
- Department of Ophthalmology, the Affiliated Hospital of Yunnan University, 176 Qing Nian Road, Kunming, 650021, China.
- Department of Ophthalmology, the Second People's Hospital of Yunnan Province, Kunming, China.
| | - Chen-Wei Pan
- School of Public Health, Medical College of Soochow University, 199 Ren Ai Road, Suzhou, 215123, China.
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Roy D, Basu S. Future research perspective on the interfacial physics of non-invasive glaucoma testing in pathogen transmission from the eyes. Biointerphases 2024; 19:018501. [PMID: 38407471 DOI: 10.1116/6.0003347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 01/25/2024] [Indexed: 02/27/2024] Open
Abstract
Non-contact tonometry (NCT) is a non-invasive ophthalmologic technique to measure intraocular pressure (IOP) using an air puff for routine glaucoma testing. Although IOP measurement using NCT has been perfected over many years, various phenomenological aspects of interfacial physics, fluid structure interaction, waves on corneal surface, and pathogen transmission routes to name a few are inherently unexplored. Research investigating the interdisciplinary physics of the ocular biointerface and of the NCT procedure is sparse and hence remains to be explored in sufficient depth. In this perspective piece, we introduce NCT and propose future research prospects that can be undertaken for a better understanding of the various hydrodynamic processes that occur during NCT from a pathogen transmission viewpoint. In particular, the research directions include the characterization and measurement of the incoming air puff, understanding the complex fluid-solid interactions occurring between the air puff and the human eye for measuring IOP, investigating the various waves that form and travel; tear film breakup and subsequent droplet formation mechanisms at various spatiotemporal length scales. Further, from an ocular disease transmission perspective, the disintegration of the tear film into droplets and aerosols poses a potential pathogen transmission route during NCT for pathogens residing in nasolacrimal and nasopharynx pathways. Adequate precautions by opthalmologist and medical practioners are therefore necessary to conduct the IOP measurements in a clinically safer way to prevent the risk associated with pathogen transmission from ocular diseases like conjunctivitis, keratitis, and COVID-19 during the NCT procedure.
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Affiliation(s)
- Durbar Roy
- Department of Mechanical Engineering, Indian Institute of Science, Bengaluru, Karnataka 560012, India
| | - Saptarshi Basu
- Department of Mechanical Engineering, Indian Institute of Science, Bengaluru, Karnataka 560012, India
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Yoo L, Kadambi N, Bohnsack BL. Corneal characteristics and OCT-angiography findings in pediatric glaucoma and glaucoma suspects. J AAPOS 2023; 27:327.e1-327.e6. [PMID: 37913864 DOI: 10.1016/j.jaapos.2023.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/20/2023] [Accepted: 09/23/2023] [Indexed: 11/03/2023]
Abstract
PURPOSE To analyze corneal biomechanics, specular microscopy, and optical coherence tomography-angiography findings in children with glaucoma. METHODS Pediatric patients (<18 years of age) with glaucoma (n = 38), increased cup:disk ratio and normal intraocular pressure (IOP) glaucoma suspects (n = 36), and controls (n = 67) were prospectively enrolled. Patients underwent testing with Ocular Response Analyzer, CellChek Specular Microscope, and Heidelberg OCT-A. RESULTS Average age of participants was 12.4 ± 3.5 years, with no difference between groups (P = 0.71). Glaucoma patients had undergone more intraocular surgeries (P < 0.0001) and showed worse logMAR visual acuity (P < 0.0001) than suspects or controls. Central corneal thickness (CCT) was greater in glaucoma patients (642.8 ± 85.9 μm [P < 0.0001]) and suspects (588 ± 43.7 μm [P = 0.003]) compared with controls (561 ± 39.9 μm). Corneal hysteresis (CH) was decreased in eyes with glaucoma (10.4 ± 3.0) compared with controls (11.7 ± 1.5 [P = 0.006]), but not suspects (11.3 ± 2.0 [P = 0.1]). Glaucoma patients had lower endothelial cell density (2028.4 ± 862.7 [P < 0.0001]) and greater average cell area (547.2 ± 332.4 [P < 0.0005]) compared with suspects (2919.3 ± 319.1, 347.5 ± 46.2) and controls (2913.7 ± 399.2, 350.8 ± 57.7), but there was no difference in polymegathism (P = 0.12) or pleomorphism (P = 0.85). No differences in vessel density or vessel skeletal density in the retinal vascular complex (P = 0.3077, P = 0.6471) or choroidal vascular complex (P = 0.3816, P = 0.7306) were detected. CONCLUSIONS Children with glaucoma showed thicker corneas with lower endothelial cell density and greater cell area, but no difference in retinal/choroidal vascular densities compared with suspects and controls.
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Affiliation(s)
- Lauren Yoo
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Namrata Kadambi
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Brenda L Bohnsack
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Division of Ophthalmology, Ann & Robert H. Lurie Children's Hospital of Chicago, Illinois.
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Chen S, Ma H, Zhao C. Corneal biomechanics after small incision lenticule extraction and femtosecond laser in situ keratomileusis: A systematic review and meta-analysis. Medicine (Baltimore) 2023; 102:e34580. [PMID: 37565903 PMCID: PMC10419641 DOI: 10.1097/md.0000000000034580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/13/2023] [Indexed: 08/12/2023] Open
Abstract
BACKGROUND Small incision lenticule extraction (SMILE) and femtosecond laser in situ keratomileusis (FS-LASIK) have been extensively studied as the main surgical methods for corneal refractive surgery. However, there is no consensus on whether SMILE is superior to FS-LASIK in corneal biomechanics. Therefore, this systematic review and meta-analysis used the results of ocular response analyzer and corvis ST to explore whether SMILE is superior to FS-LASIK in corneal biomechanics. METHODS The literature was searched in PubMed, EMBASE, and Controlled Trials Register databases. The Cochrane Collaboration's "risk of bias" tool was used to evaluate the quality of the included randomized clinical trials, and the Newcastle-Ottawa Scale was used to evaluate the included non-randomized controlled trials. The results were analyzed using Revman 5.3. RESULTS Sixteen studies (3 randomized clinical trials and 13 non-randomized controlled trials) were included in this meta-analysis. There was no statistical difference in corneal biomechanics between SMILE and FS-LASIK in corneal hysteresis [mean difference (MD), 0.20; 95% confidence interval (CI): -0.09, 0.49; P = .18] and corneal resistant factor (MD, 0.31; 95% CI: -0.09, 0.71; P = .13), A1 time (MD, -0.02; 95% CI: -0.11, 0.07; P = .66), A1 length (MD, 0.01; 95% CI: -0.01, 0.03; P = .42), A1 velocity (MD, 0.00; 95% CI: -0.01, 0.01; P = .85), A2 velocity (MD, -0.01; 95% CI: -0.11, 0.09; P = .86), HC time (MD, 0.12; 95% CI: -0.13, 0.38; P = .35), The stiffness parameter at first applanation (MD, -7.91; 95% CI: -17.96, 2.14; P = .12), The ratio between the deformation amplitude 2 mm away from apex and the apical deformation (MD, 0.01; 95% CI: -0.26, 0.27; P = .96). CONCLUSION A comprehensive assessment of the parameters of ocular response analyzer and corvis ST showed that SMILE is not superior to LASIK in corneal biomechanics 3 months post-surgery.
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Affiliation(s)
- Songbai Chen
- Aier Huangpi Eye Hospital, Wuhan, Hubei Province, China
| | - Hongjie Ma
- Zhengzhou Aier Eye Hospital, Zhengzhou, Henan Province, China
| | - Congling Zhao
- Aier Huangpi Eye Hospital, Wuhan, Hubei Province, China
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Sedaghat MR, Momeni-Moghaddam H, Ehsaei A, Vinciguerra R, Zamani O, Robabi H. Comparison of corneal biomechanical properties in healthy thin corneas with matched keratoconus eyes. J Cataract Refract Surg 2023; 49:234-238. [PMID: 36449663 DOI: 10.1097/j.jcrs.0000000000001102] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 11/16/2022] [Indexed: 12/05/2022]
Abstract
PURPOSE To compare corneal biomechanical parameters of normal thin corneas with matched keratoconus eyes. SETTING Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. DESIGN Cross-sectional comparative study. METHODS Dynamic corneal response parameters of Corvis ST were compared in 61 eyes with keratoconus with 61 matched healthy thin corneas (corneal thinnest point <500 μm), while corneal thickness, biomechanically corrected intraocular pressure, and age were considered covariates. The receiving operator sensitivity curve analysis was used to determine the cutoff point with the highest sensitivity and specificity, and the area under the curve (AUC) for each parameter. RESULTS All biomechanical parameters were statistically significant between the 2 groups except for the first ( P = .947) and second ( P = .582) applanation length, first ( P = .783) and second ( P = .301) applanation velocity, and deformation amplitude in the highest concavity phase ( P = .106). The highest mean difference between groups (12.89 ± 2.03 mm Hg/mm) was related to the stiffness parameter at the first applanation (SPA1). Although the Corvis biomechanical index and tomographic biomechanical index had the highest detection ability based on their AUC (0.912 and 0.959, respectively), among the standard and combined biomechanical parameters except for keratoconus screening parameters, the highest discriminative ability was related to SPA1 with AUC, sensitivity, and specificity of 0.793, 60.66%, and 90.16%, respectively. CONCLUSIONS Keratoconus corneas were significantly softer compared with healthy thin corneas of matched thickness. Optimal cutoff points close to the maximum value defined for screening parameters limit their clinical use for differentiation purposes in these particular types of cases.
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Affiliation(s)
- Mohammad-Reza Sedaghat
- From the Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran (Sedaghat); Rehabilitation Sciences Research Center, Zahedan University of Medical Sciences, Zahedan, Iran (Momeni-Moghaddam); Refractive Error Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran (Ehsaei); Humanitas San Pio X Hospital, Milan, Italy (Vinciguerra); Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran (Zamani); Department of Nursing and Midwifery, Zahedan University of Medical Sciences, Zahedan, Iran (Robabi)
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Salouti R, Razeghinejad R, Eslami G, Zare M, Salouti K, Ghoreyshi M, Nowroozzadeh MH. Agreement of ocular response analyzer cornea compensated IOP with corvis ST biomechanical IOP following Femtosecond Laser-assisted LASIK. Eye (Lond) 2023; 37:263-266. [PMID: 35013609 PMCID: PMC9873612 DOI: 10.1038/s41433-021-01928-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 12/08/2021] [Accepted: 12/22/2021] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVES To compare intraocular pressure (IOP) measurement by ORA-IOPcc and Corvis-bIOP after femtosecond laser-assisted LASIK (FS-LASIK). METHODS In this prospective cohort study, 56 eyes from 56 consecutive patients scheduled for FS-LASIK were enrolled. All patients had IOP measurement with ORA and Corvis ST by two blinded independent expert examiners. IOP examinations were conducted between 8 and 11 A.M. Data were collected at baseline and 3 months after FS-LASIK. RESULTS The mean age of the participants was 29.1 ± 6.3 years, and 42 (75%) were female. The average of central corneal thickness (CCT) decreased from 537 ± 23 µm at baseline to 458 ± 31 µm after FS-LASIK. The mean postoperative change of IOP was 0.0 ± 2.1 for bIOP and -2.5 ± 3.2 mmHg for IOPcc. The corresponding 95% limits of agreement (LoA) was -4.1 to 4.1 mmHg and -3.8 to 8.8 mmHg, respectively. Both methods showed no significant correlation between ∆IOP and ∆CCT. The 95% LoA between bIOP and IOPcc after FS-LASIK was -4.8 to 9.1 mmHg. CONCLUSIONS Compared to the ORA-IOPcc, the Corvis-bIOP showed less variation after FS-LASIK and might be a more appropriate choice for measuring IOP in this condition. The agreement of bIOP vs. IOPcc after FS-LASIK is below the clinically acceptable level, and the two methods could not be regarded as interchangeable.
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Affiliation(s)
- Ramin Salouti
- Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
- Salouti Cornea Research Center, Salouti Eye Clinic, Shiraz, Iran
| | | | - Gholamreza Eslami
- Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mousa Zare
- Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Kia Salouti
- Science Department, The University of British Columbia, Vancouver, Canada
| | - Maryam Ghoreyshi
- Salouti Cornea Research Center, Salouti Eye Clinic, Shiraz, Iran
- Health Policy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - M Hossein Nowroozzadeh
- Department of Ophthalmology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
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Gunay BO, Esenulku CM. Corneal biomechanical assessment via ocular response analyzer following intravitreal aflibercept therapy. SPEKTRUM DER AUGENHEILKUNDE 2022. [DOI: 10.1007/s00717-022-00534-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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14
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Changes in Corneal Morphology and Biomechanics in Cases of Small Incision Lenticule Extraction with Prophylactic Accelerated Collagen Cross-Linking. J Ophthalmol 2022; 2022:1640249. [PMID: 35859778 PMCID: PMC9293522 DOI: 10.1155/2022/1640249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 06/12/2022] [Indexed: 11/18/2022] Open
Abstract
Purpose To study the corneal morphology and biomechanics in cases of small incision lenticule extraction with prophylactic accelerated collagen cross-linking (SMILE Xtra). Methods This study was a retrospective study. 28 eyes of 14 patients with moderate-high risk of postoperative ectasia according to the Randleman scoring system underwent SMILE Xtra procedure. Outcome data were recorded including uncorrected distance visual acuity (UDVA), manifest refraction spherical equivalent (MRSE), surface regularity index (SRI), surface asymmetry index (SAI), simulated keratometry (SimK), posterior axial curvature (PAC), anterior and posterior corneal elevations (ACE and PCE), central corneal thickness (CCT), corneal resistance factor (CRF), corneal hysteresis (CH), and cornea-compensated intraocular pressure (IOPcc). The follow-up period was 12 months. Results There were 28, 26, 22, 12, and 10 eyes enrolled at postoperative 1st day and 1st, 3rd, 6th, and 12th months, respectively. The UDVA improved from 1.27 ± 0.18 logMAR preoperatively to -0.06 ± 0.04 logMAR postoperatively (P < 0.05). The MRSE improved from -5.05 ± 1.15 D preoperatively to -0.14 ± 0.30 D postoperatively (P < 0.05). SAI, SimK, PAC, PCE, and CCT all changed significantly at 1st month postoperatively (P < 0.05) and stabilized during the remainder of the follow-up (P > 0.05). There was no significant change in SRI or ACE before and after surgery (P > 0.05). CRF, CH, and IOPcc all decreased significantly at 1st month postoperatively (P < 0.05) and remained stable afterwards (P > 0.05). Conclusions The changes in the corneal morphology and biomechanics remained stable after SMILE Xtra, and there was no sign of postoperative ectasia or refractive regression. Combined with the improvement of visual and refractive results, SMILE Xtra may be a promising method for corneal refractive surgeries in patients at risk.
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Dołowiec-Kwapisz A, Misiuk-Hojło M, Piotrowska H. Cataract Surgery after Radial Keratotomy with Non-Diffractive Extended Depth of Focus Lens Implantation. MEDICINA (KAUNAS, LITHUANIA) 2022; 58:689. [PMID: 35630106 PMCID: PMC9146410 DOI: 10.3390/medicina58050689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/16/2022] [Accepted: 05/20/2022] [Indexed: 11/30/2022]
Abstract
Radial keratotomy was a popular surgical procedure used to treat myopia. Patients who underwent radial keratotomy several years ago, are currently reporting to the ophthalmologist due to worsening of vision associated with age-related cataracts. In this case report we present a case of a 60-year-old woman who underwent radial keratotomy with 16 incisions in the right eye and 12 incisions in the left eye. The patient reported to an ophthalmologist due to a deterioration of vision caused by a cataract. We described, in detail, the difficulties encountered during the diagnostic procedures, differences in the calculation of intraocular lens, and intraoperative difficulties as compared to patients who had not undergone radial keratotomy. We also present the obtained postoperative results.
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Affiliation(s)
| | - Marta Misiuk-Hojło
- Department of Ophthalmology, Wrocław Medical University, 50-556 Wrocław, Poland;
| | - Halina Piotrowska
- Department of Ophthalmology, Hospital in Zgorzelec, 59-900 Zgorzelec, Poland;
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16
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Corneal Hysteresis, Intraocular Pressure, and Progression of Glaucoma: Time for a “Hyst-Oric” Change in Clinical Practice? J Clin Med 2022; 11:jcm11102895. [PMID: 35629021 PMCID: PMC9148097 DOI: 10.3390/jcm11102895] [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] [Received: 03/27/2022] [Revised: 05/14/2022] [Accepted: 05/15/2022] [Indexed: 12/04/2022] Open
Abstract
It is known that as people age their tissues become less compliant and the ocular structures are no different. Corneal Hysteresis (CH) is a surrogate marker for ocular compliance. Low hysteresis values are associated with optic nerve damage and visual field loss, the structural and functional components of glaucomatous optic neuropathy. Presently, a range of parameters are measured to monitor and stratify glaucoma, including intraocular pressure (IOP), central corneal thickness (CCT), optical coherence tomography (OCT) scans of the retinal nerve fibre layer (RNFL) and the ganglion cell layer (GCL), and subjective measurement such as visual fields. The purpose of this review is to summarise the current evidence that CH values area risk factor for the development of glaucoma and are a marker for its progression. The authors will explain what precisely CH is, how it can be measured, and the influence that medication and surgery can have on its value. CH is likely to play an integral role in glaucoma care and could potentially be incorporated synergistically with IOP, CCT, and visual field testing to establish risk stratification modelling and progression algorithms in glaucoma management in the future.
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Qin X, Tian L, Zhang H, Zhang D, Jie Y, Zhang HX, Li L. Determine Corneal Biomechanical Parameters by Finite Element Simulation and Parametric Analysis Based on ORA Measurements. Front Bioeng Biotechnol 2022; 10:862947. [PMID: 35497338 PMCID: PMC9043460 DOI: 10.3389/fbioe.2022.862947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/23/2022] [Indexed: 11/14/2022] Open
Abstract
Purpose: The Ocular Response Analyzer (ORA) is one of the most commonly used devices to measure corneal biomechanics in vivo. Until now, the relationship between the output parameters and corneal typical biomechanical parameters was not clear. Hence, we defined the output parameters of ORA as ORA output parameters. This study aims to propose a method to determine corneal biomechanical parameters based on ORA measurements by finite element simulation and parametric analysis. Methods: Finite element analysis was used to simulate the mechanics process of ORA measurements with different intraocular pressure (IOP), corneal geometrical parameters and corneal biomechanical parameters. A simplified geometrical optics model was built to simulate the optical process of the measurements to extract ORA output parameters. After that, 70% of the simulated data was used to establish the quantitative relationship between corneal biomechanical parameters and ORA output parameters by parametric analysis and 30% of the simulated data was used to validate the established model. Besides, ten normal subjects were included to evaluate the normal range of corneal biomechanical parameters calculated from ORA. Results: The quantitative relationship between corneal biomechanical parameters and ORA output parameters is established by combining parametric analysis with finite element simulation. The elastic modulus (E) and relaxation limit (G∞) of the ten normal subjects were 0.65 ± 0.07 MPa and 0.26 ± 0.15, respectively. Conclusions: A method was proposed to determine corneal biomechanical parameters based on the results of ORA measurements. The magnitude of the corneal biomechanical parameters calculated according to our method was reasonable.
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Affiliation(s)
- Xiao Qin
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
- Medical Science Research Center, Department of Otolaryngology, Peking Union Medical College Hospital, Shuaifuyuan 1, Dongcheng District, Beijing, China
| | - Lei Tian
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
- Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University and Capital Medical University, Beijing Tongren Hospital, Beijing, China
| | - Hui Zhang
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Di Zhang
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Ying Jie
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
- *Correspondence: Ying Jie, ; Hai-Xia Zhang, ; Lin Li,
| | - Hai-Xia Zhang
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
- *Correspondence: Ying Jie, ; Hai-Xia Zhang, ; Lin Li,
| | - Lin Li
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
- *Correspondence: Ying Jie, ; Hai-Xia Zhang, ; Lin Li,
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Ye S, Bao C, Chen Y, Shen M, Lu F, Zhang S, Zhu D. Identification of Peripheral Anterior Synechia by Corneal Deformation Using Air-Puff Dynamic Anterior Segment Optical Coherence Tomography. Front Bioeng Biotechnol 2022; 10:856531. [PMID: 35433648 PMCID: PMC9011042 DOI: 10.3389/fbioe.2022.856531] [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] [Received: 01/17/2022] [Accepted: 03/07/2022] [Indexed: 11/13/2022] Open
Abstract
Indentation gonioscopy is commonly used in the clinic to evaluate peripheral anterior synechia (PAS) of angle closure glaucoma (ACG). The examination requires contacting with the cornea, resulting in an uncomfortable feeling for patients, and it only provides qualitative outcomes which may be affected by subjective judgment of the clinicians. Previous studies had reported to identify the presence of PAS by measuring the changes of morphological parameters of the anterior chamber angle (ACA) under the pupillary light reflex, by anterior segment optical coherence tomography (AS-OCT). However, this method was invalid for some subjects who had low sensitiveness to light. This article describes an air-puff dynamic anterior segment optical coherence tomography (DAS-OCT) system that can evaluate the presence of PAS in a non-contact approach. The peripheral cornea is deformed by an air puff jetted from the DAS-OCT, causing a transfer of force to the ACA, just as how indentation gonioscopy works. The dynamic changes of the ACA before and after the air puff are recorded by OCT. Ten eyes of normal subjects were enrolled in this study to validate the repeatability and availability of the measurements. Then, ten samples of the ACA from five subjects with ACG were recruited and were assigned into two groups, the non PAS group (NPAS) and PAS group, according to the results of gonioscopy. The ACA structural parameters including the angle opening distance at 750 μm to the scleral spur (AOD750) and the trabecular-iris space area at 750 μm anterior to the scleral spur (TISA750) were then calculated automatically by a custom-written algorithm. The intraclass correlation coefficient (ICC) of measured parameters was all above 0.85 for normal subjects, exhibiting good repeatability. For patients, both parameters showed significant differences between the two groups after the air puff, while no differences were observed before the air puff. AOD750dif and TISA750dif between two groups showed more significant differences, indicating that they could be used as indicators to identify the presence of PAS. In conclusion, the DAS-OCT system proposed in this study is demonstrated effective to identify the presence of PAS by measuring the changes of the ACA via a noncontact approach. It shows great potential for applications in guidance for diagnosis of angle closure glaucoma.
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Affiliation(s)
- Shuling Ye
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | | | - Yulei Chen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Meixiao Shen
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Fan Lu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
| | - Shaodan Zhang
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- *Correspondence: Shaodan Zhang, ; Dexi Zhu,
| | - Dexi Zhu
- School of Ophthalmology and Optometry, Wenzhou Medical University, Wenzhou, China
- *Correspondence: Shaodan Zhang, ; Dexi Zhu,
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Yousefi A, Roberts CJ, Reilly MA. The Shape of Corneal Deformation Alters Air Puff–Induced Loading. Front Bioeng Biotechnol 2022; 10:848060. [PMID: 35433651 PMCID: PMC9006101 DOI: 10.3389/fbioe.2022.848060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 03/03/2022] [Indexed: 12/03/2022] Open
Abstract
Purpose: To determine the dynamic modification of the load exerted on the eye during air-puff testing by accounting for the deformation of the cornea. Methods: The effect of corneal load alteration with surface shape (CLASS) was characterized as an additional component of the load produced during the concave phase where the fluid outflow tangential to the corneal surface creates backward pressure. Concave phase duration (tCD), maximum CLASS value (CLASSmax), and the area under CLASS-time curve (CLASSint) are calculated for 26 keratoconic (KCN), 102 normal (NRL), and 29 ocular hypertensive (OHT) subjects. Tukey’s HSD tests were performed to compare the three subject groups. A p-value less than 0.05 was considered statistically significant. Results: Accounting for CLASS increased the load by 34.6% ± 7.7% at maximum concavity; these differences were greater in KCN subjects (p < 0.0001) and lower in OHT subjects (p = 0.0028) than in NRL subjects. tCD and CLASSint were significantly longer and larger, respectively, for KCN subjects than those in the NRL and OHT groups (p < 0.0001). Conclusion: Load characterization is an essential step in assessing the cornea’s biomechanical response to air-puff–induced deformation. The dynamic changes in the corneal surface shape significantly alter the load experienced by the corneal apex. This implies a subject-specific loading dynamic even if the air puff itself is identical. This is important when comparing the same eye after a surgical procedure or topical medication that alters corneal properties. Stiffer corneas are least sensitive to a change in load, while more compliant corneas show higher sensitivity.
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Affiliation(s)
- Atieh Yousefi
- Department of Ophthalmology and Visual Sciences, The Ohio State University, Columbus, OH, United States
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Cynthia J. Roberts
- Department of Ophthalmology and Visual Sciences, The Ohio State University, Columbus, OH, United States
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
- *Correspondence: Cynthia J. Roberts,
| | - Matthew A. Reilly
- Department of Ophthalmology and Visual Sciences, The Ohio State University, Columbus, OH, United States
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
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20
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Vera J, Redondo B, Molina R, Jiménez R. Effects of water drinking on corneal biomechanics: The association with intraocular pressure changes. Indian J Ophthalmol 2022; 70:1222-1228. [PMID: 35326020 PMCID: PMC9240569 DOI: 10.4103/ijo.ijo_1845_21] [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] [Indexed: 11/23/2022] Open
Abstract
Purpose: We aimed to assess the impact of drinking water (500 and 1000 mL) on corneal biomechanics and determine the level of association between changes in intraocular pressure and variations in the different biomechanical properties of the cornea. Methods: A total of 39 healthy young adults ingested either 1000 mL (n = 21) or 500 mL (n = 18) of tap water in 5 min. The CorVis ST system was used to assess corneal biomechanics at baseline and at 15, 30, and 45 min after water ingestion. Results: Water drinking induced statistically significant changes in the deformation amplitude (P < 0.001, η² = 0.166), highest concavity time (P = 0.012, η² = 0.093), peak distance (P < 0.001, η² = 0.171), time and velocity of the first applanation (P < 0.001, η² = 0.288 and P = 0.016, η² = 0.087, respectively), and time and velocity of the second applanation (P = 0.030, η² = 0.074 and P = 0.001, η² = 0.132, respectively), being independent of the amount of water ingested (P > 0.05 in all cases). There were significant associations between changes in intraocular pressure and some parameters of corneal biomechanics Conclusion: Small variations in whole-body hydration status alter different biomechanical properties of the cornea, with these changes being associated with intraocular pressure levels. These findings indicate that whole-body hydration status can be considered for the diagnosis and management of different ocular conditions.
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Affiliation(s)
- Jesús Vera
- Department of Optics, Faculty of Sciences, University of Granada, Spain
| | - Beatríz Redondo
- Department of Optics, Faculty of Sciences, University of Granada, Spain
| | - Rubén Molina
- Department of Optics, Faculty of Sciences, University of Granada, Spain
| | - Raimundo Jiménez
- Department of Optics, Faculty of Sciences, University of Granada, Spain
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Boszczyk A, Kasprzak H, Przeździecka-Dołyk J. Novel Method of Measuring Corneal Viscoelasticity Using the Corvis ST Tonometer. J Clin Med 2022; 11:jcm11010261. [PMID: 35012002 PMCID: PMC8745689 DOI: 10.3390/jcm11010261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 12/21/2021] [Accepted: 12/30/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND The process of rapid propagation of the corneal deformation in air puff tonometer depends not only on intraocular pressure, but also on the biomechanical properties of the cornea and anterior eye. One of the biomechanical properties of the cornea is viscoelasticity, which is the most visible in its high-speed deformations. It seems reasonable to link the corneal viscoelasticity parameter to two moments of the highest speed of corneal deformations, when the cornea buckles. The aim of this work is to present a method of determining the time and place of occurrence of corneal buckling, examine spatial and temporal dependencies between two corneal applanations and bucklings in the Corvis ST tonometer, and correlate these dependencies with corneal viscoelastic properties. METHODS Images of the horizontal cross section of the Corvis ST deformed cornea from the air puff tonometer Corvis ST were used. 14 volunteers participated in the study, each of them had one eye measured eight times. Mutual changes in the profile slopes of the deformed corneas were numerically determined. They describe pure corneal deformation, eliminating the influence of rotation, and displacement of the entire eyeball. For each point in the central area of the corneal profile, the maximum velocities of mutual slope changes accompanying the applanations were estimated. The times of their occurrence were adopted as buckling times. RESULTS The propagation of buckling along the corneal profile is presented, as well as the repeatability and mutual correlations between the buckling parameters and intraocular pressure. Based on the relationship between them, a new parameter describing corneal hysteresis: Corvis Viscoelasticity (CVE) is introduced. It is characterized by high repeatability: ICC = 0.82 (0.69-0.93 CI) and low and insignificant correlation with intraocular pressure: r = 0.25 (p-value = 0.38). CONCLUSION The results show for the first time how to measure the corneal buckling and viscoelastic effects with Corvis ST. CVE is a new proposed biomechanical parameter related to the viscoelastic properties of the cornea, which has high repeatability for the examined subject. The distribution of its values is planned to be tested on different groups of patients in order to investigate its clinical applicability.
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Affiliation(s)
- Agnieszka Boszczyk
- Department of Optics and Photonics, Wroclaw University of Science and Technology, 50-370 Wrocław, Poland; (H.K.); (J.P.-D.)
- Correspondence:
| | - Henryk Kasprzak
- Department of Optics and Photonics, Wroclaw University of Science and Technology, 50-370 Wrocław, Poland; (H.K.); (J.P.-D.)
| | - Joanna Przeździecka-Dołyk
- Department of Optics and Photonics, Wroclaw University of Science and Technology, 50-370 Wrocław, Poland; (H.K.); (J.P.-D.)
- Department of Ophthalmology, Wroclaw Medical University, 50-556 Wrocław, Poland
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Degle S. Detektion des subklinischen Keratokonus. AUGENHEILKUNDE UP2DATE 2021. [DOI: 10.1055/a-0642-1386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
ZusammenfassungDas Frühstadium eines Keratokonus, ohne klassische und kennzeichnende klinische Befunde, stellt eine Kontraindikation für refraktive Chirurgie dar. Dieser Beitrag zeigt deshalb gemäß dem aktuellen Stand der Technik Möglichkeiten auf, Risikofaktoren für einen subklinischen Keratokonus zu erkennen.
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Degle S. [Detection of Subclinical Keratoconus]. Klin Monbl Augenheilkd 2021; 239:233-252. [PMID: 34798664 DOI: 10.1055/a-1671-0980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The early stage of a keratoconus (KC), without classic and characteristic clinical findings, is a contraindication for refractive surgery. This article therefore shows, in accordance with the current state of the art, ways of identifying risk factors for subclinical keratoconus.After delimitation, this publication contains a current summary of epidemiology, etiology and pathophysiology of subclinical and clinical KC. Furthermore, an overview of different grading scales is given. A detailed description of several practical possibilities for detection of subclinical KC is the focus of this publication: typical abnormalities with subclinical KC in ocular aberrometry, corneal topography, Zernike analysis, Fourier analysis, indices of the corneal anterior surface; especially tomography of the anterior segment of the eye respecting addition of the corneal posterior surface and the pachymetry, and also innovative techniques counting in the rigidity or biomechanical properties, as well as traditional techniques giving hints for subclinical KC as retinoscopy, ophthalmoscopy and subjective refraction.In preparation for refractive surgical interventions and to avoid possible consequences of subclinical KC, a suitable analysis with different methods should always be carried out in addition to a specific anamnesis. An exclusive consideration of the available indices is not sufficient, as this does not reveal early stages. Ideally, the biomechanics of the cornea is included in the diagnosis. The combination of tomography and biomechanics with methods of artificial intelligence are trendsetting in detection of subclinical KC.
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Effect of upper eyelid blepharoplasty on corneal biomechanical, topographic and tomographic parameters 4 weeks after surgery. Int Ophthalmol 2021; 42:113-121. [PMID: 34478004 PMCID: PMC8803703 DOI: 10.1007/s10792-021-02006-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 08/07/2021] [Indexed: 11/11/2022]
Abstract
Purpose To investigate the effect of “skin-only” upper eyelid blepharoplasty on corneal biomechanics and central as well as peripheral topographic/tomographic parameters before and 4 weeks after surgery. Methods In a prospective study, the corneal hysteresis (CH) and corneal resistance factor (CRF) were evaluated before and after blepharoplasty. Corneal topographic (maximum simulated keratometry value, inferior-superior value, index of surface variance, index of vertical asymmetry, index of height asymmetry, index of height decentration) and tomographic parameters (corneal thickness, corneal astigmatism and mean 5-mm- and 7-mm-zone keratometry value) were measured by the Pentacam HR. Statistical analysis was performed using a linear mixed model considering correlated data of both eyes. Results This study included 42 eyes of 35 patients (mean age: 64.5 years, range 52–82 years). Four weeks after surgery CH and CRF increased (9.4 ± 2.3 to 10.2 ± 2.2 mmHg and 9.7 ± 2.1 to 10.5 ± 2.2 mmHg) but did not reach statistical significance (P = 0.100 and P = 0.072). A significant increase in central maximum simulated keratometry value (Kmax) from 45.0 ± 2.3 to 45.4 ± 2.2 diopters (D) was observed (P = 0.004). Inferior-superior value (I-S) and index of surface variance (ISV) showed significant changes from 0.32 ± 0.98 to 0.10 ± 0.98 D (P = 0.02) and from 19.98 ± 9.84 to 22.93 ± 11.23 (P = 0.009), respectively. These alterations did not affect the subjective spherical equivalent (-0.09 ± 4.71 to -0.04 ± 4.51 D; P = 0.437) and the best-corrected distance visual acuity of patients (0.11 ± 0.14 to 0.15 ± 0.15 logMAR; P = 0.142). Age, gender and corneal thickness were not correlated with pre and postoperative differences of CH, CRF, corneal compensated IOP, Kmax, corneal astigmatism or I-S. Conclusion The trend of increasing CH and CRF values might indicate a rise of corneal damping capacity. Despite statistically significant differences of Kmax, I-S and ISV, all other tomographical and topographical parameters did not change 4 weeks after surgery. The corneal steepening with a mean change of 0.4 diopters and the decrease of I-S with a mean of 0.22 diopters do not seem to have a clinically relevant effect for blepharoplasty patients in daily practice.
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Elfwwal MM, Elbasty MK, Khattab MF, ElShazly MI. Comparison between different tonometers following intrastromal corneal ring segments implantation. Eur J Ophthalmol 2021; 32:43-49. [PMID: 34472983 DOI: 10.1177/11206721211042546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To compare different intraocular pressure (IOP) readings in corneas with intrastromal corneal ring segments (ICRS) taken by three different tonometers; Goldmann applanation tonometry (GAT), air puff tonometer, and ocular response analyzer (ORA) corneal-compensated IOP (ORA-IOPcc) and determine the relation of these measurements to different corneal parameters taken by Pentacam. METHODS An observational cross-sectional analytic study included patients who underwent ICRS keraring implantation at 3 months. In each eye, the two rings were placed using the femtosecond laser assisted technique 5.5 or 6 mm from the center. IOP was measured using three different tonometers; GAT, air puff tonometer, and ocular response analyzer (ORA) corneal-compensated IOP (ORA-IOPcc). RESULTS Fifty eyes of 30 patients (20 males and 10 females) aged 27.56 ± 6.38 years were included. IOP measurements by GAT, air puff tonometer, and ORA-IOPcc were 13.28 ± 2.13 mmHg, 10.47 ± 2.55 mmHg, and 13.19 ± 2.78 mmHg, respectively. Comparisons between air puff and each of GAT and ORA-IOPcc were statistically highly significant (p-value <0.001). CONCLUSION IOP measurements taken by air puff tonometer were significantly lower than those taken by GAT and ORA-IOPcc. These differences were not constant across the pressure range but increased as the pressure values determined using GAT and ORA increased. ORA-IOPcc and GAT showed similar readings. No correlation was found between any of the IOP readings taken by the three tonometers and the central corneal thickness.
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Alipour F, Hassanpoor N, Letafatnejad M, Beheshtnejad AH, Mohammadi SF. Tonometry by Ocular Response Analyzer in Keratoconic and Warpage Eyes in Comparison with Normal Eyes. J Curr Ophthalmol 2021; 33:118-123. [PMID: 34409220 PMCID: PMC8365575 DOI: 10.4103/joco.joco_147_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 10/17/2020] [Accepted: 02/06/2021] [Indexed: 11/04/2022] Open
Abstract
Purpose To compare intraocular pressure (IOP) values measured by ocular response analyzer (ORA) in contact lens-induced corneal warpage, normal, and keratoconic eyes. Methods In a prospective, observational case-control study, 94 eyes of 47 warpage-suspected cases and 46 eyes of 23 keratoconic patients were enrolled. Warpage-suspected cases were followed until a definite diagnosis was made (warpage, nonwarpage normal, or keratoconus). ORA tonometry and corneal biomechanics testing were performed for all cases in each visit. We had 2-3 measured corneal-compensated IOP (IOPcc) and Goldmann-correlated IOP (IOPg) for each patient (based on group) with at least 2-week interval. Results After following up of warpage-suspected patients, finally 44 eyes of 22 patients had confirmed soft contact lens-related corneal warpage. Forty-six eyes of 23 people were finally diagnosed as nonwarpage normal eyes. Forty-six eyes of 23 known keratoconus patients were also included for comparison. The demographic and refractive data were not different between the warpage and nonwarpage normal groups but were different in the keratoconus group. Both IOPcc and IOPg were statistically different with the highest value in the warpage group followed by normal and keratoconus groups; the same trend was observed in central corneal thickness (CCT). The mean of IOPg was 14.94 ± 2.65, 13.7 ± 2.33, and 10.86 ± 3 and IOPcc was 15.73 ± 2.4, 15.28 ± 2.43, and 14.08 ± 2.55 in the warpage, normal, and keratoconus groups, respectively. IOPg and IOPcc in the warpage group (based on baseline diagnosis) did not regress to become closer to IOP of normal eyes after discontinuation of contact lens in their follow-up visits (P value for IOPg and IOPcc trends in the warpage group was 0.07 and 0.09 controlling for CCT, respectively). Both IOPcc and IOPg were significantly lower in keratoconic eyes in comparison with normal eyes. After correction for the confounding effect of CCT, a lower IOPcc in keratoconus versus warpage remained significant (P = 0.02). Conclusion Both IOPcc and IOPg were statistically different with the highest value in the warpage group followed by normal and keratoconus groups, just like their CCT. After correction for the confounding effect of CCT, there was no statistically significant difference between the three groups in their measured IOPcc and IOPg except for IOPcc in keratoconus versus warpage (P = 0.02).
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Affiliation(s)
- Fateme Alipour
- Eye Research Center, Department of Ophthalmology, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Narges Hassanpoor
- Eye Research Center, Department of Ophthalmology, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran.,Department of Ophthalmology, Tabriz University of Medical Sciences, Nikookari Eye Hospital, Tabriz, Iran
| | - Moggan Letafatnejad
- Department of Health Services Management, School of Health Management and Information Sciences, Iran University of Medical Sciences, Tehran, Iran
| | - Amir-Hooshang Beheshtnejad
- Eye Research Center, Department of Ophthalmology, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyed-Farzad Mohammadi
- Eye Research Center, Department of Ophthalmology, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
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Lee SJ, Lee SH, Lee MS, Jo YH, Shin HJ, Lee AG. Morphological changes after lower eyelid epiblepharon surgery in Asian children. BMC Ophthalmol 2021; 21:293. [PMID: 34362336 PMCID: PMC8348859 DOI: 10.1186/s12886-021-02052-9] [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: 12/19/2020] [Accepted: 07/17/2021] [Indexed: 11/10/2022] Open
Abstract
Background This study aimed to determine the morphological changes in Asian lower eyelid epiblepharon patients after surgery. Methods The medical records of 59 patients who underwent lower eyelid epiblepharon repair were reviewed retrospectively. Eighty-nine patients who underwent strabismus surgery were set as the control group. The photographs for each group were analyzed based on the following factors: inferior half area (IHA) of the eye, eyelash angular direction (EAD), angle between the eyelashes and the cornea, marginal reflex distance 1 (MRD1) and marginal reflex distance 2 (MRD2). Results After surgery, the medial EAD changed from 92.45° ± 20.21° (mean ± SD) to 79.43° ± 23.31°, while the central and lateral EADs were unchanged. IHA increased from 36.33 ± 9.78 mm3 to 43.06 ± 10.57 mm3, and MRD1 increased from 1.92 ± 0.99 mm to 2.50 ± 0.93 mm, whereas MRD2 did not change. The mean angle between the eyelashes and the cornea increased from 39.64° to 72.19° immediately postoperatively, but had reduced to 58.75° 3 months later, followed by no further significant change at the 6-month and 9-month postoperative follow-ups. Conclusions There is morphological changes of the eyelid after lower eyelid epiblepharon surgery, with increases in the IHA and MRD1. In addition, contact between the eyelashes and the cornea occurred mainly in the medial portion of the eyelid the position, which everted and stabilized over 3 months. Thus, follow-up observations are required for at least 3 months to properly evaluate the surgical outcome.
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Affiliation(s)
- Sang Jae Lee
- School of Medicine, Konkuk University, Seoul, Republic of Korea
| | - Shin-Hyo Lee
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Min Sub Lee
- Department of Ophthalmology, Research Institute of Medical Science, Konkuk University Medical Center, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, Republic of Korea, 143-701
| | - Youn Hye Jo
- Department of Ophthalmology, Research Institute of Medical Science, Konkuk University Medical Center, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, Republic of Korea, 143-701
| | - Hyun Jin Shin
- Department of Ophthalmology, Research Institute of Medical Science, Konkuk University Medical Center, Konkuk University School of Medicine, 120 Neungdong-ro, Gwangjin-gu, Seoul, Republic of Korea, 143-701.
| | - Andrew G Lee
- Department of Ophthalmology, Blanton Eye Institute, Houston Methodist Hospital, Houston, TX, USA.,Department of Ophthalmology, Neurology, Neurosurgery, Weill Cornell Medicine, New York, NY, USA.,Department of Ophthalmology, University of Texas Medical Branch, Galveston, TX, USA.,Department of Ophthalmology, UT MD Anderson Cancer Center, Houston, TX, USA.,Department of Ophthalmology, Texas A and M College of Medicine, College Station, TX, USA.,Department of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City, IA, USA.,Department of Ophthalmology, Baylor College of Medicine and the Center for Space Medicine, Houston, TX, USA.,Department of Ophthalmology, University of Buffalo, Buffalo, NY, USA
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Systemic supplemental oxygen therapy during accelerated corneal crosslinking for progressive keratoconus: randomized clinical trial. J Cataract Refract Surg 2021; 47:773-779. [PMID: 33252568 DOI: 10.1097/j.jcrs.0000000000000513] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 11/04/2020] [Indexed: 02/03/2023]
Abstract
PURPOSE To investigate the potential additive effect of systemic supplemental oxygen administered during accelerated corneal crosslinking (CXL) for progressive keratoconus (KC). SETTING Academic center. DESIGN Randomized clinical trial. METHODS Eyes with progressive KC randomized to 3 different CXL protocols were included. The first group (OA-CXL) included 19 eyes that underwent an accelerated CXL protocol (9 mW/cm2 for 10 minutes) while receiving systemic oxygen at a rate of 5 L/min for 10 minutes. The second group consisted of 14 eyes undergoing the same accelerated CXL protocol without supplemental oxygen therapy (A-CXL). The third group (C-CXL) comprised 14 eyes undergoing conventional CXL according to the Dresden protocol. All subjects were followed up for at least 6 months. Visual acuity, keratometry and corneal biomechanical parameters including corneal hysteresis and corneal resistance factor (CRF) were measured preoperatively and 6 months postoperatively. RESULTS Reduction in maximum keratometry (Kmax) was significantly greater in the OA-CXL group (P = .01). At baseline, the mean Kmax was 54.31 ± 3.64 diopters (D) in the OA-CXL group, 54.66 ± 4.99 D in the A-CXL group, and 56.03 ± 5.28 D in the C-CXL group (P = .58), which reached 53.58 ± 3.24 D, 54.59 ± 4.65 D, and 55.87 ± 4.73 D at 6 months in the 3 study groups, respectively (P = .115). The mean CRF increased significantly only in the OA-CXL group from a baseline value of 6.32 ± 2.12 mm Hg to 7.38 ± 1.88 mm Hg at 6 months (P = .009). CONCLUSIONS This study suggests superior efficacy of an accelerated CXL protocol coupled with systemic oxygen supplementation when compared with the accelerated CXL protocol and the conventional protocol in eyes with progressive KC. In addition to greater reduction in Kmax as the primary outcome, improvement in corneal biomechanics was also observed at 6 months.
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Wu Y, Guo LL, Tian L, Xu ZQ, Li Q, Hu J, Huang YF, Wang LQ. Comparative analysis of the morphological and biomechanical properties of normal cornea and keratoconus at different stages. Int Ophthalmol 2021; 41:3699-3711. [PMID: 34232432 PMCID: PMC8536578 DOI: 10.1007/s10792-021-01929-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 06/19/2021] [Indexed: 11/07/2022]
Abstract
Purpose To compare the morphological and biomechanical properties of normal cornea and keratoconus at different stages. Methods A total of 408 patients (517 eyes) with keratoconus were included in this study. According to the Topographic Keratoconus (TKC) grading method, keratoconus was divided into stage I (TKC = 1, 130 eyes), stage II (TKC = 1–2, 2, 164 eyes), stage III (TKC = 2–3, 3, 125 eyes) and stage IV (TKC = 3–4, 4, 98 eyes). A total of 158 normal subjects (158 eyes) were recruited as the normal group. The corneal morphological parameters and biomechanical parameters were obtained with Scheimpflug tomography (Pentacam) and corneal visualization Scheimpflug technology (Corvis ST), and the receiver operating characteristic (ROC) curves were drawn. Results Each corneal morphological and most biomechanical parameters of the keratoconic eyes were significantly different from those of the normal eyes in this study (p < 0.001). ROC curve demonstrated that most parameters in this study showed high efficiency in diagnosing keratoconus (the area under the ROC (AUC) was > 0.9), with the Belin-Ambrósio deviation (BAD-D) and Tomographic and Biomechanical Index (TBI) showing higher efficiency. The efficiency of BAD-D and TBI was high in differentiating keratoconus at different stages (AUC > 0.963). The comparison of ROC curves of keratoconus at different stages did not reveal statistically significant differences for TBI. Conclusion BAD-D and TBI can effectively diagnose stage I keratoconus. Moreover, the efficiency of TBI is the same in diagnosing keratoconus at all stages, while the diagnostic efficiency of other parameters increases with the increase in keratoconus stages.
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Affiliation(s)
- Ying Wu
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Li-Li Guo
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China
| | - Lei Tian
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China. .,Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University and Capital Medical University, Beijing Tongren Hospital, Beijing, 100730, China.
| | - Ze-Quan Xu
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Qian Li
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Jian Hu
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Yi-Fei Huang
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China
| | - Li-Qiang Wang
- Department of Ophthalmology, Chinese People's Liberation Army General Hospital, Beijing, 100853, China.
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Herber R, Pillunat LE, Raiskup F. Development of a classification system based on corneal biomechanical properties using artificial intelligence predicting keratoconus severity. EYE AND VISION 2021; 8:21. [PMID: 34059127 PMCID: PMC8167942 DOI: 10.1186/s40662-021-00244-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 05/06/2021] [Indexed: 01/03/2023]
Abstract
Background To investigate machine-learning (ML) algorithms to differentiate corneal biomechanical properties between different topographical stages of keratoconus (KC) by dynamic Scheimpflug tonometry (CST, Corvis ST, Oculus, Wetzlar, Germany). In the following, ML models were used to predict the severity in a training and validation dataset. Methods Three hundred and eighteen keratoconic and one hundred sixteen healthy eyes were included in this monocentric and cross-sectional pilot study. Dynamic corneal response (DCR) and corneal thickness related (pachymetric) parameters from CST were chosen by appropriated selection techniques to develop a ML algorithm. The stage of KC was determined by the topographical keratoconus classification system (TKC, Pentacam, Oculus). Patients who were classified as TKC 1, TKC 2 and TKC 3 were assigned to subgroup mild, moderate, and advanced KC. If patients were classified as TKC 1–2, TKC 2–3 or TKC 3–4, they were assigned to subgroups according to the normative range of further corneal indices (index of surface variance, keratoconus index and minimum radius). Patients classified as TKC 4 were not included in this study due to the limited amount of cases. Linear discriminant analysis (LDA) and random forest (RF) algorithms were used to develop the classification models. Data were divided into training (70% of cases) and validation (30% of cases) datasets. Results LDA model predicted healthy, mild, moderate, and advanced KC eyes with a sensitivity (Sn)/specificity (Sp) of 82%/97%, 73%/81%, 62%/83% and 68%/95% from a validation dataset, respectively. For the RF model, a Sn/Sp of 91%/94%, 80%/90%, 63%/87%, 72%/95% could be reached for predicting healthy, mild, moderate, and advanced KC eyes, respectively. The overall accuracy of LDA and RF was 71% and 78%, respectively. The accuracy for KC detection including all subgroups of KC severity was 93% in both models. Conclusion The RF model showed good accuracy in predicting healthy eyes and various stages of KC. The accuracy was superior with respect to the LDA model. The clinical importance of the models is that the standalone dynamic Scheimpflug tonometry is able to predict the severity of KC without having the keratometric data. Trial registration NCT04251143 at Clinicaltrials.gov, registered at 12 March 2018 (Retrospectively registered). Supplementary Information The online version contains supplementary material available at 10.1186/s40662-021-00244-4.
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Affiliation(s)
- Robert Herber
- Department of Ophthalmology, University Hospital Carl Gustav Carus, Universitätsklinikum Carl Gustav Carus an der Technischen Universität Dresden, Fetscherstraße 74, TU 01307, Dresden, Germany.
| | - Lutz E Pillunat
- Department of Ophthalmology, University Hospital Carl Gustav Carus, Universitätsklinikum Carl Gustav Carus an der Technischen Universität Dresden, Fetscherstraße 74, TU 01307, Dresden, Germany
| | - Frederik Raiskup
- Department of Ophthalmology, University Hospital Carl Gustav Carus, Universitätsklinikum Carl Gustav Carus an der Technischen Universität Dresden, Fetscherstraße 74, TU 01307, Dresden, Germany
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Ma J, Wang Y, Li M, Jhanji V. Association Between Severity of Myopia and Deformation Characteristics of the Cornea Based on Propensity Score Matching Analysis. J Refract Surg 2021; 37:344-350. [PMID: 34044695 DOI: 10.3928/1081597x-20210222-02] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To investigate the relationship between severity of myopia and corneal deformation characteristics after removing confounding factors using propensity score matching (PSM) analysis. METHODS A prospective study was conducted from April 1 to December 30, 2019 in Tianjin Eye Hospital. Participants were divided into low (spherical equivalent [SE] > -6.00 diopters) and high (SE ⩽ -6.00 diopters) myopia groups. Corneal deformation parameters were obtained using corneal visualization Scheimpflug technology. PSM analysis was conducted to minimize the effect of confounding factors (age, intraocular pressure, and corneal thickness) on corneal deformation. Correlation analysis and logistic regression models were applied to investigate the relationships between SE and corneal deformation parameters. RESULTS A total of 2,126 eyes from 1,063 patients with a mean age of 23.81 ± 5.68 years were enrolled. The left and right eyes were analyzed separately. After PSM analysis, logistic regression indicated that the peak distance was a significant indicator for high myopia in both eye models (left: odds ratio [OR] = 1.978, 95% CI: 1.303 to 3.004; right: OR = 2.089, 95% CI: 1.362 to 3.202; P < .001). The maximum amplitudes of deformation and deflection and peak distance were significantly negatively correlated with SE in both eyes, whereas the whole eye movement was significantly positively correlated with SE (P < .01), as well as the deformation amplitude at the second applanation (P < .001). CONCLUSIONS Eyes with high myopia exhibited larger deformation and deflection amplitude compared to eyes with low myopia. The high distance between bending points of the cornea at the highest concavity (peak distance) may be a feature of high myopia. [J Refract Surg. 2021;37(5):344-350.].
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Synergic effect of corneal hysteresis and central corneal thickness in the risk of early-stage primary open-angle glaucoma progression. Graefes Arch Clin Exp Ophthalmol 2021; 259:2743-2751. [PMID: 33961110 DOI: 10.1007/s00417-021-05212-1] [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] [Received: 09/02/2020] [Revised: 03/09/2021] [Accepted: 04/19/2021] [Indexed: 10/21/2022] Open
Abstract
PURPOSE To evaluate corneal hysteresis (CH), acquired with ocular response analyzer (ORA), as a risk factor for glaucoma progression in early-stage primary open-angle glaucoma (POAG). METHODS In a historical cohort study, patients diagnosed in 2011 with early-stage POAG according to the Hodapp, Parrish and Anderson classification modified for Octopus perimetry and followed up until glaucomatous progression development; otherwise, observations were censored in October 2018. Cox regression was used to obtain hazard ratios (HR) to evaluate baseline variables (CH, central corneal thickness, gender, age IOP and glaucoma family history) as risk factors for perimetric glaucoma progression. A likelihood ratio test for interaction was performed in order to assess the effect of the combination of CH and CCT on the risk of progression. RESULTS Of the cohort of 1573 patients, 11.38% developed early-stage POAG progression during the follow-up. The mean follow-up time was 3.28 ± 1.92 years. Patients without progression had a higher CH (11.35 ± 1.43 vs 9.07 ± 1.69 mmHg; p < 0.001) and CCT (570.75 ± 17.71 vs 554.51 ± 23.20; p < 0.001). In the multivariate analysis, each 1 mmHg of lower CH was associated with an increase of 2.13 times in the HR of progression (95% CI: 1.92-2.32; p < 0.001). CH hazard ratio was modified by CCT, with higher values of CCT and CH resulting in a higher HR of early glaucoma progression (p < 0.001). CONCLUSIONS CH can be considered as a risk factor of progression in early-stage POAG. The risk associated with CH changed depending on CCT values, acting synergistically slowing the risk of glaucoma progression with higher values.
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Guo LL, Tian L, Cao K, Li YX, Li N, Yang WQ, Jie Y. Comparison of the morphological and biomechanical characteristics of keratoconus, forme fruste keratoconus, and normal corneas. Semin Ophthalmol 2021; 36:671-678. [PMID: 33734947 DOI: 10.1080/08820538.2021.1896752] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Purpose: To explore the feasibility of corneal morphological and biomechanical parameters for keratoconus and forme fruste keratoconus diagnosis.Methods: This case-control study included a total of 517 eyes from 408 keratoconus patients (KC group), 83 eyes from 83 forme fruste keratoconus patients (FFKC group), and 158 eyes from 158 patients with normal corneas (NL group). All subjects underwent routine ophthalmologic examinations. Pentacam and Corneal Visualization Scheimpflug Technology (Corvis ST) were used to obtain corneal morphological and biomechanical parameters. Differences between groups were compared using receiver operating characteristic (ROC) curve analysis.Results: ROC analysis showed that all corneal morphological parameters and most biomechanical parameters distinguished KC from NL, with an area under the curve (AUC) greater than 0.80, of which Belin-Ambrósio enhanced ectasia total deviation index (BAD-D) and tomographic and biomechanical index (TBI) were most efficient. The AUC for distinguishing KC from NL of the BAD-D was 0.989 and the TBI was 0.993, which were not statistically significant (DeLong et al., P= .232). The BAD-D cut-off point of 1.595 provided 95.9% sensitivity for distinguishing KC from NL with 100% specificity. The TBI cut-off point of 0.515 provided 96.7% sensitivity for distinguishing KC from NL with 100% specificity. The ability of other parameters to distinguish KC from NL was lower than that of BAD and TBI. Except for central astigmatism from the anterior corneal surface (AstigF), the AUC that distinguished FFKC from NL was 0.862. The AstigF cut-off point of 4.65 provided 73.5% sensitivity for distinguishing FFKC from NL with 99.3% specificity. Other parameters distinguished FFKC from NL with low efficiency. Among them, the AUC for distinguishing FFKC from NL of the TBI was 0.722, whose cut-off point of 0.273 provided 55.4% sensitivity for distinguishing KC from NL with 79.7% specificity.Conclusion: BAD-D and TBI have the highest efficiency, sensitivity, and specificity for distinguishing KC from NL. Except for AstigF, other corneal morphological and biomechanical parameters have a relatively low ability to distinguish FFKC from NL.
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Affiliation(s)
- Li-Li Guo
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
| | - Lei Tian
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China.,Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University & Capital Medical University, Beijing, China
| | - Kai Cao
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
| | - Yu-Xin Li
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
| | - Na Li
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
| | - Wei-Qiang Yang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
| | - Ying Jie
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
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Chou CC, Shih PJ, Lin HC, Chen JP, Yen JY, Wang IJ. Changes in Intraocular Pressure after Transepithelial Photorefractive Keratectomy and Femtosecond Laser In Situ Keratomileusis. J Ophthalmol 2021; 2021:5592195. [PMID: 33777445 PMCID: PMC7972855 DOI: 10.1155/2021/5592195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/22/2021] [Accepted: 02/28/2021] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate the changes in intraocular pressure (IOP) and biomechanically corrected IOP (bIOP) in patients undergoing transepithelial photorefractive keratectomy (TPRK) and femtosecond laser in situ keratomileusis (FS-LASIK) and to determine the effects of preoperative biomechanical factors on IOP and bIOP changes after FS-LASIK and TPRK. DESIGN A retrospective comparative study. METHODS We retrospectively investigated the IOP and corneal biomechanical changes in 93 eyes undergoing FS-LASIK and 104 eyes undergoing TPRK in a clinical setting. Preoperative and postoperative data on ophthalmic and Corvis ST examinations, in vivo Young's modulus, and noncontact tonometry were analyzed. Marginal linear regression models with generalized estimating equations were used for intragroup and intergroup comparisons of IOP and bIOP changes. RESULTS In the univariate model, IOP reduction after FS-LASIK was 2.49 mmHg higher than that after TPRK. In addition, bIOP reduction after FS-LASIK was 1.85 mmHg higher than that after TPRK. In the multiple regression model, we revealed that IOP reduction after FS-LASIK was 1.75 mmHg higher than that after TPRK. Additionally, bIOP reduction after FS-LASIK was 1.64 mmHg higher than that after TPRK. Postoperative changes in bIOP were less than those in IOP. In addition, Young's modulus and CBI had no significant effect on postoperative IOP and bIOP changes. We establish a biomechanically predictive model using the available data to predict postoperative IOP and bIOP changes after TPRK and FS-LASIK. CONCLUSIONS Reductions in IOP and bIOP after FS-LASIK were 1.75 mmHg and 1.64 mmHg, respectively, more than those after TPRK, after adjustment for confounders. We revealed that the type of refractive surgery and peak distance (PD) were significant predictors of postoperative IOP and bIOP changes. By contrast, depth of ablation showed a significant effect on only IOP changes.
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Affiliation(s)
- Chien-Chih Chou
- Department of Ophthalmology, Taichung Veterans General Hospital, Taichung, Taiwan
- Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Po-Jen Shih
- Department of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
| | - Hung-Chou Lin
- Dr. Lin's Eye Clinic and Laser Vision Correction Center, Taoyuan, Taiwan
| | - Jun-Peng Chen
- Biostatistics Task Force of Taichung Veterans General Hospital, Taichung, Taiwan
| | - Jia-Yush Yen
- Department of Mechanical Engineering, National Taiwan University, Taipei, Taiwan
| | - I-Jong Wang
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan
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Abstract
PURPOSE Diabetes mellitus (DM) induces changes in corneal biomechanical properties. The influence of disease-specific factors was evaluated, and a novel DM index was created. METHODS Eighty-one patients with DM and 75 healthy subjects were matched according to age, intraocular pressure, and central corneal thickness. Information on the disease was collected, and measurements with the Ocular Response Analyzer and the Corvis ST were taken. Results were compared between the groups, and the influence of disease-specific factors was evaluated. From dynamic corneal response parameters, a DM index was calculated. RESULTS In DM, corneal hysteresis was higher than in healthy subjects (10.5 ± 1.9 vs. 9.7 ± 1.9 mm Hg, P = 0.008). In addition, dynamic corneal response parameters showed significant differences. Among others, highest concavity (HC) (17.212 ± 0.444 vs. 16.632 ± 0.794 ms, P < 0.001) and A2 time (21.85 ± 0.459 vs. 21.674 ± 0.447 ms, P = 0.017) as well as A1 (0.108 ± 0.008 vs. 0.104 ± 0.011 mm, P = 0.019) and A2 deflection amplitudes (0.127 ± 0.014 vs. 0.119 ± 0.014 mm, P < 0.001) were increased in DM. In DM type 1, HC deformation amplitude (1.14 ± 0.19 vs. 1.095 ± 0.114 mm, P = 0.035) was higher than in type 2. The time of deflection amplitude max correlated with the severity of retinopathy (R = 0.254, P= 0.023). In case of diabetic maculopathy, A1 velocity (0.155 ± 0.018 vs. 0.144 ± 0.019 ms, P = 0.043) and A2 time (22.052 ± 0.395 vs. 21.79 ± 0.46 ms, P = 0.04) were increased. Deformation amplitude max (R = 0.297, P = 0.024), HC time (R = 0.26, P = 0.049), HC deformation amplitude (R = 0.297, P = 0.024), and A2 deformation amplitude (R = 0.276, P = 0.036) were associated to disease duration. The DM index revealed a sensitivity of 0.773 and a specificity of 0.808 (area under the curve of receiver operating characteristic = 0.833). CONCLUSIONS In DM, changes in corneal biomechanics were correlated with disease-specific factors. The DM index achieved reliable sensitivity and specificity values.
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Colakoglu A, Colakoglu IE, Cosar CB. Correlation between corneal thickness, keratometry, age, and differential pressure difference in healthy eyes. Sci Rep 2021; 11:4133. [PMID: 33603061 PMCID: PMC7893151 DOI: 10.1038/s41598-021-83683-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/03/2021] [Indexed: 01/31/2023] Open
Abstract
To determine the use of differential pressure difference (DPD), in air-puff differential tonometry, as a potential biomechanical measure of the cornea and elucidate its relationship with the intraocular pressure (IOP), central corneal thickness, corneal curvature, and age. This study comprised 396 eyes from 198 patients and was conducted at Acibadem University, School of Medicine, Department of Ophthalmology, Istanbul, Turkey. The central corneal curvature and refraction of the eyes were measured using an Auto Kerato-Refractometer (KR-1; Topcon Corporation, Tokyo, Japan). IOP and central corneal thickness were measured using a tono-pachymeter (CT-1P; Topcon Corporation, Tokyo, Japan), wherein two separate readings of IOP were obtained using two different modes: 1-30 and 1-60. The difference between these two readings was recorded as the DPD. The factors affecting the DPD were determined by stepwise multiple linear regression analysis. DPD varied over a dynamic range of - 3.0 to + 5.0 mmHg and was weakly correlated with the central corneal thickness (r = 0.115, p < 0.05). DPD showed no significant correlation with IOP 1-30 (p > 0.05). A weak but statistically significant (p < 0.05) positive correlation of DPD was observed with age (r = 0.123), Kavg (r = 0.102), and the CCT (r = 0.115). There was a significant correlation between DPD and Kavg, CCT, and age. There was no significant correlation between DPD and IOP 1-30. Age-related changes in the corneal ultrastructure may be a plausible explanation for the weak positive association between age and DPD. The proposed method may prove a valid non-invasive tool for the evaluation of corneal biomechanics and introduce DPD in the decision-making of routine clinical practice.
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Affiliation(s)
- Ahmet Colakoglu
- Department of Ophthalmology, Acibadem University School of Medicine, Icerenkoy, 34752, Istanbul, Turkey.
| | | | - Cemile Banu Cosar
- Department of Ophthalmology, Acibadem University School of Medicine, Icerenkoy, 34752, Istanbul, Turkey
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Konstantinidis A, Panagiotopoulou EK, Panos GD, Sideroudi H, Mehmet A, Labiris G. The Effect of Antiglaucoma Procedures (Trabeculectomy vs. Ex-PRESS Glaucoma Drainage Implant) on the Corneal Biomechanical Properties. J Clin Med 2021; 10:jcm10040802. [PMID: 33671167 PMCID: PMC7922603 DOI: 10.3390/jcm10040802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 02/09/2021] [Accepted: 02/13/2021] [Indexed: 11/03/2022] Open
Abstract
The aim of this study is to investigate the effect of two antiglaucoma procedures, namely trabeculectomy and Ex-PRESS mini-shunt insertion on the biomechanical properties of the cornea. This is a prospective study. Thirty patients (30 eyes) were included in the study. Nineteen eyes had an Ex-PRESS shunt inserted (Group 1) and 11 had trabeculectomy (Group 2). The examination time points for both groups were one to three weeks preoperatively and at month 1, 6, and 12 postoperatively. Corneal biomechanical properties (corneal hysteresis (CH) corneal resistance factor (CRF)) were measured with the Ocular Response Analyzer (ORA). In group 1, CH was significantly increased at 6 and 12 months compared to baseline values. Corneal hysteresis was also higher at 1 month postoperatively, but this increase did not reach statistical significance. In group 2, the CH was significantly increased at all time points compared to the preoperative values. CRF decreased at all time points postoperatively compared to the preoperative values in both groups. The difference (preoperative values to postoperative values at all time points) of the CH and CRF between the two groups was also compared and no significant differences were detected between the two surgical techniques. Trabeculectomy and the EX-PRESS mini-shunt insertion significantly alter the corneal biomechanical properties as a result of the surgical trauma and the presence of the shunt in the corneal periphery. When compared between them, they affect the corneal biomechanical properties in a similar way.
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Changes in Corneal Biomechanics and Glaucomatous Visual Field Loss. J Glaucoma 2021; 30:e246-e251. [PMID: 33596020 DOI: 10.1097/ijg.0000000000001819] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 01/25/2021] [Indexed: 11/25/2022]
Abstract
PRECIS A lower baseline corneal hysteresis and a decrease in corneal resistance factor (CRF) over time are associated with higher risk of visual field progression in glaucomatous and glaucoma suspect eyes. PURPOSE The aim was to investigate the longitudinal change in CRF and cornea hysteresis (CH) as risk factors for visual field progression. MATERIALS AND METHODS In this prospective observational cohort study, 72 eyes of 48 glaucoma or glaucoma suspect patients were followed for an average of 4.5 years. Baseline and follow-up CH and CRF measurements were performed with the Ocular Response Analyzer (Reichert Ophthalmic Instruments Inc., Depew, N.Y.). Evaluation of rates of visual field change during follow-up was performed using visual field mean deviation. Univariable and multivariable linear mixed models assessed the relationship of visual field progression with baseline CRF and CH as well as with changes in CRF and CH. RESULTS The mean baseline CH was 9.0 (95% confidence interval: 8.6-9.4) mm Hg and the mean baseline CRF was 9.3 (95% confidence interval: 8.8-9.9) mm Hg. There was no statistically significant difference in average CH and CRF measurements over time. In multivariable modeling adjusting for age, race, and mean intraocular pressure during follow-up, each 1 mm Hg lower in baseline CH and 1 mm Hg decrease in CRF over time were associated with a 0.12 (P=0.042) and 0.14 dB/year (P=0.007) faster rate of visual field mean deviation loss, respectively. Similar findings were found in glaucoma eyes but not found in glaucoma suspect eyes. CONCLUSION Visual field progression was associated with a lower baseline CH and a decrease in CRF over time. Assessment of corneal resistance and elasticity at baseline and during follow-up examinations should be considered to identify those eyes at highest risk of visual field progression.
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The Relationship Between Corneal Hysteresis and Progression of Glaucoma After Trabeculectomy. J Glaucoma 2021; 29:912-917. [PMID: 32555063 DOI: 10.1097/ijg.0000000000001581] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The purpose of this study was to investigate the association of corneal hysteresis (CH) measured with Ocular Response Analyzer on the progression of glaucoma after trabeculectomy. MATERIALS AND METHODS Twenty-four eyes of 19 patients with primary open-angle glaucoma underwent trabeculectomy. A series of visual fields (Humphery Field Analyzer 24-2 SITA-standard) were measured starting after 6 months after trabeculectomy (4.2±5.0 y, mean±SD). The mean total deviation (mTD) of the 52 test points were calculated. In addition, the mTD was divided into the following areas: central area (within central 10 degrees), superior area and inferior area: mTDcentre, mTDsuperior, and mTDinferior, respectively. The relationship between each area's progression rate of mTD and the 7 variables of baseline age, central corneal thickness, baseline mTD, mean intraocular pressure (IOP), SD of IOP divided by the mean IOP, the difference between baseline IOP obtained before the initiation of any treatment, mean IOP, and CH were analyzed using the linear mixed model, and the optimal model was selected using the model selection method with the second ordered Akaike Information Criterion. RESULTS In the optimal model for mTD progression rate, only CH was selected with the coefficient of 0.11. The optimal model for the mTDcentre progression rate included mean IOP with the coefficient of -0.043 and CH with the coefficient of 0.12, and that for mTDinferior included only CH with the coefficient of 0.089. There was no variable selected in the optimal model for the mTDsuperior progression rate. CONCLUSION CH is a useful measure in the management of glaucoma after trabeculectomy.
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Zhang H, Tian L, Guo L, Qin X, Zhang D, Li L, Jie Y, Zhang H. Comprehensive evaluation of corneas from normal, forme fruste keratoconus and clinical keratoconus patients using morphological and biomechanical properties. Int Ophthalmol 2021; 41:1247-1259. [PMID: 33389426 PMCID: PMC8035106 DOI: 10.1007/s10792-020-01679-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 12/02/2020] [Indexed: 11/02/2022]
Abstract
OBJECTIVE To more comprehensively evaluate the ability of the parameters reflecting the morphological and biomechanical properties of the cornea to distinguish clinical keratoconus (CKC) and forme fruste keratoconus (FFKC) from normal. METHODS Normal eyes (n = 50), CKC (n = 45) and FFKC (n = 15) were analyzed using Pentacam, Corvis ST and ORA. Stepwise logistic regression of all parameters was performed to obtain the optimal combination model capable of distinguishing CKC, FFKC from normal, named SLR1 and SLR2, respectively. Receiver operating characteristic (ROC) curves were applied to determine the predictive accuracy of the parameters and the two combination models, as described by the area under the curve (AUC). AUCs were compared using the DeLong method. RESULTS The SLR1 model included only the TBI output by Pentacam, while the SLR2 model included the morphological parameter F.Ele.Th and two parameters from the Corvis ST, HC DfA and SP-A1. The majority of the parameters had sufficient strength to differentiate the CKC from normal corneas, even the seven separate parameters and the SLR1 model had a discrimination efficiency of 100%. The predictive accuracy of the parameters was moderate for FFKC, and the SLR2 model (0.965) presented an excellent AUC, followed by TBI, F.Ele.Th and BAD-D. CONCLUSION The F.Ele.Th from Pentacam was the most sensitive morphological parameter for FFKC, and the combination of F.Ele.Th, HC DfA and SP-A1 made the diagnosis of FFKC more efficient. The CRF and CH output by ORA did not improve the combined diagnosis, despite the corneal combination of morphological and biomechanical properties that optimized the diagnosis of FFKC.
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Affiliation(s)
- Hui Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China.,Beijing Key Laboratory of Fundamental Research On Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China
| | - Lei Tian
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University and Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China.,Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University & Capital Medical University, Beijing Tongren Hospital, Beijing, 100730, China
| | - Lili Guo
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University and Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China
| | - Xiao Qin
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China.,Beijing Key Laboratory of Fundamental Research On Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China
| | - Di Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China.,Beijing Key Laboratory of Fundamental Research On Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China
| | - Lin Li
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China.,Beijing Key Laboratory of Fundamental Research On Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China
| | - Ying Jie
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University and Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, 100730, China.
| | - Haixia Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China. .,Beijing Key Laboratory of Fundamental Research On Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China.
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The Relationship Between Corvis ST Tonometry Parameters and Ocular Response Analyzer Corneal Hysteresis. J Glaucoma 2020; 29:479-484. [PMID: 32134829 DOI: 10.1097/ijg.0000000000001486] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PRECIS Corvis ST Tonometry and Ocular Response Analyzer (ORA) measurements were conducted in primary open-angle glaucoma and normative subjects. Many parameters were significantly correlated, however, the strengths were weak to moderate. PURPOSE Reichert ORA parameters are derived from pressure information following the application of air-jet, whereas detailed structural observation can be made using the Corneal Visualization Scheimpflug Technology instrument (CST). The purpose of the study was to investigate the association between CST measurements and ORA measured corneal hysteresis (CH). METHODS Measurements of CST, ORA, axial length, average corneal curvature, central corneal thickness (CCT) and intraocular pressure with Goldmann applanation tonometry were carried out in 104 eyes of 104 patients with primary open-angle glaucoma and 35 eyes from normative subjects. The association between CST and ORA parameters was assessed using linear regression analysis, with model selection based on the second order bias corrected Akaike Information Criterion index. RESULTS Deformation amplitude ratio (corneal softness, R=-0.51), SP A1 (corneal stiffness, R=0.41), and Inverse Radius (integrated area under the curve of the inverse concave radius, R=-0.44) were significantly correlated with CH (P <0.05). The optimal model to explain CH using CST measurements was given by: CH=-76.3+4.6×A1 time (applanation time in the corneal inward movement)+1.9×A2 time (second applanation time in the corneal outward movement) + 3.1 × highest concavity deformation amplitude (magnitude of movement of the corneal apex from before deformation to its highest concavity) + 0.016×CCT (R=0.67; P<0.001). CONCLUSIONS CST parameters are significant, but weakly or moderately, related to ORA measured CH.
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Taroni L, Bernabei F, Pellegrini M, Roda M, Toschi PG, Mahmoud AM, Schiavi C, Giannaccare G, Roberts CJ. Corneal Biomechanical Response Alteration After Scleral Buckling Surgery for Rhegmatogenous Retinal Detachment. Am J Ophthalmol 2020; 217:49-54. [PMID: 32283097 DOI: 10.1016/j.ajo.2020.03.054] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/25/2020] [Accepted: 03/31/2020] [Indexed: 12/17/2022]
Abstract
PURPOSE To compare the corneal biomechanics of eyes that underwent scleral buckle (SB) for rhegmatogenous retinal detachment (RRD) with those of fellow eyes (fellow eyes) and to further investigate the effects of SB on intraocular pressure (IOP) values. DESIGN Retrospective, fellow-eye matched cohort study. METHODS A total of 18 consecutive patients (11 males and 7 females) treated with SB for RRD in 1 eye were enrolled. Goldmann applanation tonometry was used to measure IOP. Biomechanical properties of the cornea were investigated by using the Ocular Response Analyzer (ORA) (Reichert Instruments) for the calculation of corneal resistant factor (CRF), corneal hysteresis, Goldmann-correlated IOP, and corneal-compensated IOP. Customized software was used for analysis of the ORA infrared and pressure signals, and a significance threshold was set to a P value of .05. RESULTS Operated eyes (OEs) showed significantly lower values of corneal hysteresis and CRF than fellow eyes (9.0 ± 1.8 vs 10.1 ± 1.8 mm Hg, respectively; P < .001; 10.0 ± 2.2 vs 10.9 ± 2.2 mm Hg; P < .001). GAT was significantly lower than corneal-compensated IOP in OEs (18.1 ± 4.9 vs 19.8 ± 4.8 mm Hg, respectively; P = .022) but not in fellow eyes. The second applanation event (A2) took place earlier in time, and the cornea was moving faster during A2 in the OEs than in the fellow eyes. CONCLUSIONS SB for the treatment of RRD affects corneal biomechanical response, likely due to a less compliant sclera that limits corneal motion and reduces energy dissipation, reflected in a lower corneal hysteresis. This has potentially meaningful clinical implications as the accuracy of the measurement of IOP values may be affected in these eyes.
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Affiliation(s)
- Leonardo Taroni
- Department of Ophthalmology, S.Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy.
| | - Federico Bernabei
- Department of Ophthalmology, S.Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy
| | - Marco Pellegrini
- Department of Ophthalmology, S.Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy
| | - Matilde Roda
- Department of Ophthalmology, S.Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy
| | - Pier Giorgio Toschi
- Department of Ophthalmology, S.Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy
| | - Ashraf M Mahmoud
- Department of Ophthalmology and Visual Science and Department of Biomedical Engineering, Ohio State University, Columbus, Ohio, USA
| | - Costantino Schiavi
- Department of Ophthalmology, S.Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy
| | - Giuseppe Giannaccare
- Department of Ophthalmology, S.Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy; Department of Ophthalmology, University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Cynthia J Roberts
- Department of Ophthalmology and Visual Science and Department of Biomedical Engineering, Ohio State University, Columbus, Ohio, USA
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Zhang X, Munir SZ, Sami Karim SA, Munir WM. A review of imaging modalities for detecting early keratoconus. Eye (Lond) 2020; 35:173-187. [PMID: 32678352 DOI: 10.1038/s41433-020-1039-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/28/2020] [Accepted: 06/10/2020] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVES Early identification of keratoconus is imperative for preventing iatrogenic corneal ectasia and allowing for early corneal collagen cross-linking treatments to potentially halt progression and decrease transplant burden. However, early diagnosis of keratoconus is currently a diagnostic challenge as there is no uniform screening criteria. We performed a review of the current literature to assess imaging modalities that can be used to help identify subclinical keratoconus. METHODS A Pubmed database search was conducted. We included primary and empirical studies for evaluating different modalities of screening for subclinical keratoconus. RESULTS A combination of multiple imaging tools, including corneal topography, tomography, Scheimpflug imaging, anterior segment optical coherence tomography, and in vivo confocal microscopy will allow for enhanced determination of subclinical keratoconus. In patients who are diagnostically borderline using a single screening criteria, use of additional imaging techniques can assist in diagnosis. Modalities that show promise but need further research include polarization-sensitive optical coherence tomography, Brillouin microscopy, and atomic force microscopy. CONCLUSIONS Recognition of early keratoconus can reduce risk of post-refractive ectasia and reduce transplantation burden. Though there are no current uniform screening criterion, multiple imaging modalities have shown promise in assisting with the early detection of keratoconus.
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Affiliation(s)
- Xuemin Zhang
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Saleha Z Munir
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Syed A Sami Karim
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Wuqaas M Munir
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, Baltimore, MD, USA.
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Rahman N, O'Neill E, Irnaten M, Wallace D, O'Brien C. Corneal Stiffness and Collagen Cross-Linking Proteins in Glaucoma: Potential for Novel Therapeutic Strategy. J Ocul Pharmacol Ther 2020; 36:582-594. [PMID: 32667842 DOI: 10.1089/jop.2019.0118] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Biomechanical properties of the cornea have recently emerged as clinically useful in risk assessment of diagnosing glaucoma and predicting disease progression. Corneal hysteresis (CH) is a dynamic tool, which measures viscoelasticity of the cornea. It represents the overall deformability of the cornea, and reduces significantly with age. Low CH has also been associated with optic nerve damage and progression of visual field loss in glaucoma. The extracellular matrix (ECM) constituents of the cornea, trabecular meshwork (TM), sclera, and lamina cribrosa (LC) are similar, as they are predominantly made of fibrillar collagen. This suggests that biomechanical changes in the cornea may also reflect optic nerve compliance in glaucomatous optic neuropathy, and in the known increase of TM tissue stiffness in glaucoma. Increased collagen cross-linking contributes to tissue stiffening throughout the body, which is observed in normal aging and occurs at an accelerated rate in systemic conditions such as fibrotic and cardiovascular diseases, cancer, and glaucoma. We reviewed 3 ECM cross-linking proteins that may have a potential role in the disease process of increased tissue stiffness in glaucoma, including lysyl oxidase (LOX)/lysyl oxidase-like 1 (LOXL1), tissue transglutaminase (TG2), and advanced glycation end products. We also report elevated messenger RNA (mRNA) levels of LOX and TG2 in glaucoma LC cells to support our proposed theory that increased levels of cross-linking proteins in glaucoma play a role in LC tissue stiffness. We highlight areas of research that are needed to better understand the role of cross-linking in glaucoma pathogenesis, leading potentially to a novel therapeutic strategy.
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Affiliation(s)
- Najiha Rahman
- UCD Department of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland
| | - Evelyn O'Neill
- UCD Department of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland
| | - Mustapha Irnaten
- UCD Clinical Research, Catherine Mcauley Centre, Dublin, Ireland
| | - Deborah Wallace
- UCD Clinical Research, Catherine Mcauley Centre, Dublin, Ireland
| | - Colm O'Brien
- UCD Department of Ophthalmology, Mater Misericordiae University Hospital, Dublin, Ireland.,UCD Clinical Research, Catherine Mcauley Centre, Dublin, Ireland
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Edris NA, Arfeen SA, Mosaad R, Nassar GA. Evaluation of Corneal Biomechanical Parameters in Psoriasis Patients: A Controlled Study. Clin Ophthalmol 2020; 14:1833-1837. [PMID: 32636611 PMCID: PMC7335276 DOI: 10.2147/opth.s256629] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/16/2020] [Indexed: 11/26/2022] Open
Abstract
Purpose To evaluate corneal biomechanical parameters with an ocular response analyzer (ORA) in patients with psoriasis and compare these parameters with age-matched control subjects. Study Design This was a cross-sectional observational case–control study. Methods Thirty eyes of 15 psoriasis patients were included in the study and compared with 30 eyes of 15 control subjects. Corneal biomechanical properties were calculated by ORA. Central corneal thickness (CCT) was measured by anterior-segment optical coherence tomography. The main outcome measures were corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc), and Goldmann-correlated IOP (IOPg). For dry-eye evaluation, Schirmer’s test was used. Results Mean CH in the psoriasis group was 10.20±1.55 mmHg and in the control group 10.66±1.36 mmHg (p=0.215). Mean CRF in the psoriasis group was 9.76±1.60 mmHg and in the control group 10.97±1.42 mmHg (p=0.003). Mean IOPcc in the psoriasis group was 14.84±3.43 mmHg and in the control group 16.67±3.17 mmHg (p=0.035). Mean IOPg in the psoriasis group was 13.92±3.35 mmHg and in the control group 16.62±3.10 mmHg (p=0.002). Mean CCT in the psoriasis group was 543.90±37.27 µm and in the control group 551.23±28.63 µm (p=0.392). Schirmer’s test results in the psoriasis group were 11.4±1.57 mm/5 min and in the control group 17.5±1.52 mm/5 min (p<0.001). Conclusion Psoriasis affects corneal biomechanical properties with statistically significantly lower corneal biomechanics than normal. CH correlates negatively with disease activity. These corneal biomechanical changes should be considered when determining IOP values and during corneal evaluation for keratoconus-suspected patients.
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Affiliation(s)
- Noha A Edris
- Ophthalmology Department, Cairo University, Faculty of Medicine, Cairo, Egypt
| | - Shaimaa A Arfeen
- Ophthalmology Department, Cairo University, Faculty of Medicine, Cairo, Egypt
| | - Rana Mosaad
- Dermatology Department, Cairo University, Faculty of Medicine, Cairo, Egypt
| | - Ghada A Nassar
- Ophthalmology Department, Cairo University, Faculty of Medicine, Cairo, Egypt
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Corneal Topographic, Anatomic, and Biomechanical Properties in Severe Obstructive Sleep Apnea-Hypopnea Syndrome. Cornea 2020; 39:88-91. [PMID: 31414996 DOI: 10.1097/ico.0000000000002102] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To determine corneal topographic, anatomic, and biomechanical properties in patients newly diagnosed with severe obstructive sleep apnea-hypopnea syndrome (OSAHS). METHODS This is a cross-sectional study including 25 patients recently diagnosed with severe OSAHS (apnea-hypopnea index above 30) and a paired control group of 25 healthy subjects. All patients underwent a complete eye examination with an elevation topography Pentacam Scheimpflug study and a study with Reichert Ocular Response Analyzer, collecting several topographic, anatomic, and biomechanical variables. RESULTS Fifty eyes of 25 patients (23 of them were men) diagnosed with OSAHS by somnography and the same number of healthy subjects (23 of them were men) were included, with an average age of 64 ± 11 years (range 45-78 years) for cases and an average age of 64 ± 11 years (range 45-81 years) for the controls. No differences were found in keratometry, cylinder, refractive indexes, Bad-D, or pachymetry. The mean corneal volume for cases was 58.64 ± 3.05 mm and for the controls 60.48 ± 3.33 mm (P = 0.005). The mean minimum radius for cases was 7.49 ± 0.31 and for the controls 7.36 ± 0.30 (P = 0.035). The mean elevation in apex for cases was 8.46 ± 5.18 and for the controls 2.38 ± 2.36 (P ≤ 0.001). Two eyes with a topographic diagnosis of keratoconus (KC) and another 6 with subclinical KC were detected using the Pentacam in the OSAHS group. CONCLUSIONS Many of the corneal topographic and biomechanical variables in patients with severe OSAHS present different values from the general population with a trend toward KC values, such as keratoconus index or paired keratoconus index. Compared with the control group, significant differences were found in corneal volume, corneal elevation, and minimum radius.
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Chun H, Moon JI, Jung Y. Analysis of Factors Affecting Corneal Deflection Amplitude in Normal Korean Eyes. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2020. [DOI: 10.3341/jkos.2020.61.5.538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Corneal Biomechanical Changes After Uneventful Phacoemulsification in Patients With Type 2 Diabetes Mellitus and Patients Without Diabetes. Cornea 2020; 39:1073-1079. [PMID: 32301813 DOI: 10.1097/ico.0000000000002332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To compare corneal biomechanical changes after uneventful phacoemulsification cataract surgery between type 2 diabetic (DM) and nondiabetic patients. METHODS Forty-four diabetic (44 eyes) and 44 (44 eyes) age and sex-matched non-DM controls with age-related cataract were enrolled in this prospective observational study. Corneal hysteresis (CH), corneal resistance factor (CRF), and corneal-compensated intraocular pressure (IOPcc) were evaluated by using the ocular response analyzer; central corneal thickness was recorded by using the Pentacam HR. Patients were evaluated preoperatively and 1 and 6 months after surgery. RESULTS In the DM group, CH was observed to be significantly lower than preoperative value (9.8 ± 1.5 mm Hg) at 1 month (9.4 ± 1.2 mm Hg, P = 0.040), but not at the 6-month follow-up (9.6 ± 1.6 mm Hg, P = 0.437),whereas it did not change significantly in the non-DM group (preoperative 9.8 ± 1.3 mm Hg vs. 1 month 9.6 ± 1.1 mm Hg vs. 6 months 10.1 ± 1.1 mm Hg, P > 0.05). CRF was significantly lower than the preoperative values at 1 and 6 months in both groups (P ≤ 0.001). Postoperative CH change was significantly associated with preoperative CH (P < 0.001), preoperative IOPcc (P = 0.004), and IOPcc change (P < 0.001), whereas CRF change was only correlated with preoperative CRF (P < 0.001). There was a significant postoperative IOPcc reduction 6 months after surgery (P < 0.001) in both DM and non-DM groups; however, central corneal thickness was not found to significantly change in the postoperative period (P > 0.05). CONCLUSIONS This study showed that phacoemulsification causes a significant and persistent decrease in intraocular pressure and CRF in both groups, whereas CH recovered to preoperative values, although more slowly in patients with diabetes.
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Kato N, Negishi K, Sakai C, Tsubota K. Baseline factors predicting the need for corneal crosslinking in patients with keratoconus. PLoS One 2020; 15:e0231439. [PMID: 32298314 PMCID: PMC7162475 DOI: 10.1371/journal.pone.0231439] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 03/15/2020] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION The primary purpose of crosslinking is to halt the progression of ectasia. We retrospectively assessed the condition of keratoconus patients who were followed-up at least twice after the initial examination to evaluate keratoconus progression, to identify definitive factors to predict a later need for corneal crosslinking (CXL). METHODS The medical charts of 158 eyes of 158 keratoconus patients (112 males and 46 females; mean age, 27.8 ± 11.7 years), who were followed up at the Department of Ophthalmology, Keio University School of Medicine at least twice after the initial examination to evaluate keratoconus progression were retrospectively reviewed. Best-spectacle corrected visual acuity, intraocular pressure, steepest corneal axis on the anterior float (Ks), thinnest corneal thickness according to Pentacam® HR, and corneal endothelial cell density were assessed. Gender, age, onset age of keratoconus, history of atopic dermatitis, and Pentacam® indices were also recorded. CXL was performed when the eye showed significant keratoconus progression, an increase in the steepest keratometric value, or an increase in the spherical equivalent or cylinder power of the manifest refraction by more than 1.0 D versus the respective values 2 years prior. Predictor variables and the requirement for CXL were analyzed using logistic regression. RESULTS Fifty-eight eyes required CXL treatment. The best predictor of the requirement for CXL was patient age, followed by the Pentacam® Rmin (the minimum sagittal curvature evaluated by Pentacam®) value. The incidence of CXL was 86.4% in the < 20 years age group, with an Rmin of ≤ 5.73 mm, whereas 10.8% in the ≥ 27 years age group with an Rmin > 5.73 mm underwent treatment. CONCLUSIONS An age of < 20 years and an Rmin value of ≤ 5.73 mm predicted keratoconus progression and the requirement for CXL treatment in the near future.
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Affiliation(s)
- Naoko Kato
- Minamiaoyama Eye Clinic, Tokyo, Japan
- Department of Ophthalmology, School of Medicine, Keio University, Tokyo, Japan
- * E-mail:
| | - Kazuno Negishi
- Department of Ophthalmology, School of Medicine, Keio University, Tokyo, Japan
| | - Chikako Sakai
- Department of Ophthalmology, School of Medicine, Keio University, Tokyo, Japan
| | - Kazuo Tsubota
- Department of Ophthalmology, School of Medicine, Keio University, Tokyo, Japan
- Tsubota Laboratory, Inc., Tokyo, Japan
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Esporcatte LPG, Salomão MQ, Lopes BT, Vinciguerra P, Vinciguerra R, Roberts C, Elsheikh A, Dawson DG, Ambrósio R. Biomechanical diagnostics of the cornea. EYE AND VISION 2020; 7:9. [PMID: 32042837 PMCID: PMC7001259 DOI: 10.1186/s40662-020-0174-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 01/08/2020] [Indexed: 02/06/2023]
Abstract
Corneal biomechanics has been a hot topic for research in contemporary ophthalmology due to its prospective applications in diagnosis, management, and treatment of several clinical conditions, including glaucoma, elective keratorefractive surgery, and different corneal diseases. The clinical biomechanical investigation has become of great importance in the setting of refractive surgery to identify patients at higher risk of developing iatrogenic ectasia after laser vision correction. This review discusses the latest developments in the detection of corneal ectatic diseases. These developments should be considered in conjunction with multimodal corneal and refractive imaging, including Placido-disk based corneal topography, Scheimpflug corneal tomography, anterior segment tomography, spectral-domain optical coherence tomography (SD-OCT), very-high-frequency ultrasound (VHF-US), ocular biometry, and ocular wavefront measurements. The ocular response analyzer (ORA) and the Corvis ST are non-contact tonometry systems that provide a clinical corneal biomechanical assessment. More recently, Brillouin optical microscopy has been demonstrated to provide in vivo biomechanical measurements. The integration of tomographic and biomechanical data into artificial intelligence techniques has demonstrated the ability to increase the accuracy to detect ectatic disease and characterize the inherent susceptibility for biomechanical failure and ectasia progression, which is a severe complication after laser vision correction.
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Affiliation(s)
- Louise Pellegrino Gomes Esporcatte
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil.,Instituto de Olhos Renato Ambrósio, Rua Conde de Bonfim 211 / 712, Rio de Janeiro, RJ 20520-050 Brazil.,3Department of Ophthalmology, Hospital São Vicente de Paulo, Rio de Janeiro, Brazil
| | - Marcella Q Salomão
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil.,Instituto de Olhos Renato Ambrósio, Rua Conde de Bonfim 211 / 712, Rio de Janeiro, RJ 20520-050 Brazil.,Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BrAIN, Rio de Janeiro & Maceió, Brazil.,5Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil.,Instituto Benjamin Constant, Rio de Janeiro, Brazil
| | - Bernardo T Lopes
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil.,7School of Engineering, University of Liverpool, Liverpool, L69 3GH UK
| | - Paolo Vinciguerra
- 8Department of Biomedical Science, Humanitas University, Rozzano, Italy.,9Eye Center, Humanitas Clinical and Research Center, Rozzano, Italy
| | - Riccardo Vinciguerra
- 7School of Engineering, University of Liverpool, Liverpool, L69 3GH UK.,Department of Ophthalmology, Humanitas San Pio X Hospital, Milan, Italy
| | - Cynthia Roberts
- 11Department of Ophthalmology and Visual Science, Department of Biomedical Engineering, The Ohio State University, Columbus, OH USA
| | - Ahmed Elsheikh
- 7School of Engineering, University of Liverpool, Liverpool, L69 3GH UK.,12School of Biological Science and Biomedical Engineering, Beihang University, Beijing, China.,13NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
| | - Daniel G Dawson
- 14The University of Florida Department of Ophthalmology, Gainesville, FL USA
| | - Renato Ambrósio
- Rio de Janeiro Corneal Tomography and Biomechanics Study Group, Rio de Janeiro, Brazil.,Instituto de Olhos Renato Ambrósio, Rua Conde de Bonfim 211 / 712, Rio de Janeiro, RJ 20520-050 Brazil.,Brazilian Study Group of Artificial Intelligence and Corneal Analysis - BrAIN, Rio de Janeiro & Maceió, Brazil.,5Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil.,15Department of Ophthalmology, Federal University the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil
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