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Kaya O, Akif Aydin M, Teymoori M, Kaan Erden O, Sadeghzadeh S, Dedeoglu UO, Demir S, Muhikanci O, Sahin A, Torun H, Dundar G, Yalcinkaya AD. A first-in-human pilot study of a novel electrically-passive metamaterial-inspired resonator-based ocular sensor embedded contact lens monitoring intraocular pressure fluctuations. Cont Lens Anterior Eye 2024; 47:102102. [PMID: 38114379 DOI: 10.1016/j.clae.2023.102102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 11/29/2023] [Accepted: 12/03/2023] [Indexed: 12/21/2023]
Abstract
Glaucoma is a leading cause of blindness with no cure, but early treatment and effective monitoring can often slow the progression of the disease. Monitoring of glaucoma is based on the measurement of intra-ocular pressure (IOP) that is a physiological parameter related to the mechanical state and parameters of the eye. Conventionally, diagnosing and assessing the progression of glaucoma is based on the method of measuring IOP discretely at clinics. Recent studies have demonstrated the importance of continuously monitoring IOP for 24 h to elucidate the effect of circadian rhythm. In this work, a metamaterial-inspired electrically-passive sensor-embedded contact lens is presented to monitor the IOP fluctuations based on a first-in-human pilot study. The sensor inside the contact lens is an electrically passive, metamaterial-based resonator that can be measured using a wearable antenna patch. The system has been tested with six healthy volunteers during an experiment to induce deliberate IOP changes via water-loading and placing the individuals in supine position using a recliner seat. The initial data compared with tonometer measurements suggest that the system can be used to assess the variation of IOP continuously.
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Affiliation(s)
- Ozgur Kaya
- Glakolens, Bogazici Universitesi Teknopark 302, 34470 Istanbul, Turkiye
| | - M Akif Aydin
- Glakolens, Bogazici Universitesi Teknopark 302, 34470 Istanbul, Turkiye
| | - Morteza Teymoori
- Glakolens, Bogazici Universitesi Teknopark 302, 34470 Istanbul, Turkiye
| | - Oguz Kaan Erden
- Glakolens, Bogazici Universitesi Teknopark 302, 34470 Istanbul, Turkiye
| | | | - Ulas O Dedeoglu
- Glakolens, Bogazici Universitesi Teknopark 302, 34470 Istanbul, Turkiye
| | - Saibe Demir
- Glakolens, Bogazici Universitesi Teknopark 302, 34470 Istanbul, Turkiye
| | - Omer Muhikanci
- Glakolens, Bogazici Universitesi Teknopark 302, 34470 Istanbul, Turkiye
| | - Afsun Sahin
- Department of Ophthalmology, Koc University Medical School, Istanbul, Turkiye
| | - Hamdi Torun
- Faculty of Engineering & Environment, University of Northumbria, Newcastle Upon Tyne, NE1 8ST, UK.
| | - Gunhan Dundar
- Department of Electrical and Electronics Engineering, Bogazici University, Bebek 34342 Istanbul, Turkiye
| | - Arda D Yalcinkaya
- Department of Electrical and Electronics Engineering, Bogazici University, Bebek 34342 Istanbul, Turkiye
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Wu THY, Lau HKC, Lai CHY, Wong RWL, Wong AKW, Lam AKC. Effect of digital ocular massage on intraocular pressure and Schlemm's canal dimensions. Sci Rep 2024; 14:6112. [PMID: 38480777 PMCID: PMC10937985 DOI: 10.1038/s41598-024-56748-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Accepted: 03/11/2024] [Indexed: 03/17/2024] Open
Abstract
Digital ocular massage has been reported to temporarily lower intraocular pressure (IOP). This could be related to an enhanced aqueous humor outflow; however, the mechanism is not clearly understood. Using anterior segment optical coherence tomography, the Schlemm's canal (SC) and trabecular meshwork (TM) can be imaged and measured. Here, 66 healthy adults underwent digital ocular massage for 10 min in their right eyes. The IOP and dimensions of the SC and TM were measured before and after ocular massage. All subjects demonstrated IOP reduction from 15.7 ± 2.5 mmHg at baseline to 9.6 ± 2.2 mmHg immediately after, and median of 11.6 mmHg 5-min after ocular massage (Friedman's test, p < 0.001). There was significant change in SC area (median 10,063.5 μm2 at baseline to median 10,151.0 μm2 after ocular massage, Wilcoxon test, p = 0.02), and TM thickness (median 149.8 μm at baseline to 144.6 ± 25.3 μm after ocular massage, Wilcoxon test, p = 0.036). One-third of the subjects demonstrated collapse of the SC area (-2 to -52%), while two-thirds showed expansion of the SC area (2 to 168%). There were no significant changes in SC diameter (270.4 ± 84.1 μm vs. 276.5 ± 68.7 μm, paired t-test, p = 0.499), and TM width (733.3 ± 110.1 μm vs. 733.5 ± 111.6 μm, paired t-test, p = 0.988). Eyes with a higher baseline IOP demonstrated a greater IOP reduction (Pearson correlation coefficient r = -0.521, p < 0.001). Eyes with smaller SC area at baseline showed greater SC area expansion (Pearson correlation coefficient = -0.389, p < 0.001). Greater IOP reduction appeared in eyes with greater SC area expansion (Pearson correlation coefficient r = -0.306, p = 0.01). Association between change in IOP and change in TM thickness was not significant (Spearman's ρ = 0.015, p = 0.902). Simple digital ocular massage is an effective method to lower IOP values, and change in the SC area was significantly associated with IOP changes.
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Affiliation(s)
- Tiffany H Y Wu
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Henry K C Lau
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Carmelo H Y Lai
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Ruby W L Wong
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Antonia K W Wong
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Andrew Kwok-Cheung Lam
- School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
- Research Centre for SHARP Vision, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
- Centre for Eye and Vision Research, 17W Hong Kong Science Park, Science Park, Hong Kong.
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Keller WJ. International comparisons of intraocular pressures, as measured by Tono-Pen and Goldmann applanation tonometry, in healthy adults: A meta-analysis. Medicine (Baltimore) 2023; 102:e33078. [PMID: 36897721 PMCID: PMC9997780 DOI: 10.1097/md.0000000000033078] [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: 01/07/2023] [Accepted: 02/02/2023] [Indexed: 03/11/2023] Open
Abstract
BACKGROUND Investigate intraocular pressure (IOP), as measured by Tono-Pen (TP) and Goldmann applanation tonometry (GAT), in healthy adults. Provide an updated synthesis of multinational, primary studies, reported during the 10-year period 2011 to 2021 and offer an evidence-based benchmark, against which IOP can be evaluated across subject variables and pathologies. Three primary research questions are investigated: Is there a statistically significant difference between IOP measured by TP and GAT? If yes, is the difference clinically significant? Is measurement of IOP affected by the country or setting location, in which the measurements are made? METHODS An aggregate meta-analysis was conducted on 22 primary studies, from 15 different countries. IOP measurements were made from each healthy adult subject, with both the TP and GAT. Primary studies were identified and data extracted according to recommended preferred reporting items for systematic reviews and meta-analysis protocol guidelines. Meta-analysis summary results are reported as the point estimate of the raw mean difference of IOP. RESULTS Meta-analysis reveals a statistically significant difference in raw mean differences in IOP, when measured by TP and GAT, in the healthy adult population. Tono-Pen IOP measurements are higher than GAT IOP measurements. The point estimate for the summary effect size = -0.73 mm Hg, P = .03. The prediction interval for the true effect size, in 95% of all comparable populations, is -4.03 to 2.58 mm Hg. There is no clinically significance difference in IOP when measured by TP and GAT. Meta-regression analysis reveals statistically significant differences in measurement of IOP by countries, R2 analog = 0.75, P = .001. There is no statistically significant difference in measurement of IOP as a function of measurement location setting, R2 analog = -0.17, P = .65. CONCLUSIONS IOP measured by TP are marginally higher compared to GAT, in the healthy adult population. However, from a clinical practice perspective, TP and GAT produce similar IOP measurements. There is evidence of significant variabilities in IOP measurements as a function of country. IOP measurements collected in a research laboratory setting are similar to IOP collected in a clinical setting. Results have implications for the primary care physician requiring a portable, inexpensive, reliable, and easily administered instrument to assess IOP.
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Affiliation(s)
- William J. Keller
- Medical Education, Nova Southeastern University, Kiran C. Patel College of Allopathic Medicine (NSU-MD), Fort Lauderdale, Florida, USA
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Intraocular Pressure Measurements in Standing, Sitting, and Supine Position: Comparison between Tono-Pen Avia and Icare Pro Tonometers. J Clin Med 2022; 11:jcm11216234. [PMID: 36362460 PMCID: PMC9654527 DOI: 10.3390/jcm11216234] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 10/18/2022] [Accepted: 10/20/2022] [Indexed: 11/25/2022] Open
Abstract
Background: Intraocular pressure (IOP) is influenced by body position. The purpose of this study is to compare the IOP measurements obtained with two different devices, to investigate IOP changes in standing, sitting, and supine positions. Methods: In this comparative prospective case series, IOP was measured in sitting, supine, prone, and standing (standing 1) positions and again five minutes after standing (standing 2), utilizing an Icare Pro (ICP) and a Tono-Pen Avia (TPA) in the 64 eyes of 32 healthy subjects. Results: Compared to the sitting position, both devices showed an increase in the IOP both in supine and standing 2 positions (p < 0.05). The mean IOP difference between the two devices was: in the sitting position, 0.57 ± 2.10 mmHg (range: −3.80 to 6.60 mmHg) (p < 0.05), in the supine position, 0.93 ± 2.49 mmHg (range: −4.50 to 7.10 mmHg) (p < 0.05), in the standing 1 position, 0.37 ± 1.96 mmHg (range: −5.20 to 5.00 mmHg) (p = 0.102), and in the standing 2 position 0.73 ± 2.03 mmHg (range: −4.5 to 6.4 mmHg) (p < 0.001). Conclusions: The results highlight an agreement between the TPA and ICP, both confirming not only the increase in IOP in the supine position, but also showing an increase in the standing 2 position. Therefore, it is suggested to perform such measurements in patients with glaucoma, to explain its progression in an apparently normal tension or in compensated patients.
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Agorastou V, Schön J, Verma-Fuehring R, Dakroub M, Hillenkamp J, Puppe F, Loewen NA. HIOP-Reader: Automated Data Extraction for the Analysis of Manually Recorded Nycthemeral IOPs and Glaucoma Progression. Transl Vis Sci Technol 2022; 11:22. [PMID: 35737376 PMCID: PMC9233288 DOI: 10.1167/tvst.11.6.22] [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] [Indexed: 11/24/2022] Open
Abstract
Purpose Nycthemeral (24-hour) intraocular pressure (IOP) monitoring in glaucoma has been used in Europe for more than 100 years to detect peaks missed during regular office hours. Data supporting this practice are lacking, because it is difficult to correlate manually drawn IOP curves to objective glaucoma progression. To address this, we developed an automated IOP data extraction tool, HIOP-Reader. Methods Machine learning image analysis software extracted IOP data from hand-drawn, nycthemeral IOP curves of 225 retrospectively identified patients with glaucoma. The relationship between demographic parameters, IOP, and mean ocular perfusion pressure (MOPP) data to spectral-domain optical coherence tomography (SDOCT) data was analyzed. Sensitivities and specificities for the historical cutoff values of 15 mm Hg and 22 mm Hg in detecting glaucoma progression were calculated. Results Machine data extraction was 119 times faster than manual data extraction. The IOP average was 15.2 ± 4.0 mm Hg, nycthemeral IOP variation was 6.9 ± 4.2 mm Hg, and MOPP was 59.1 ± 8.9 mm Hg. Peak IOP occurred at 10 am and trough at 9 pm. Progression occurred mainly in the temporal-superior and temporal-inferior SDOCT sectors. No correlation could be established between demographic, IOP, or MOPP variables and disease progression on OCT. The sensitivity and specificity of both cutoff points (15 and 22 mm Hg) were insufficient to be clinically useful. Outpatient IOPs were noninferior to nycthemeral IOPs. Conclusions IOP data obtained during a single visit make for a poor diagnostic tool, no matter whether obtained using nycthemeral measurements or during outpatient hours. Translational Relevance HIOP-Reader rapidly extracts manually recorded IOP data to allow critical analysis of existing databases.
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Affiliation(s)
- Vaia Agorastou
- Department of Ophthalmology, University of Würzburg, Würzburg, Germany
| | - Julian Schön
- Institute for Artificial Intelligence and Knowledge Systems, Department of Informatics, University of Würzburg, Würzburg, Germany
| | | | - Mohamad Dakroub
- Department of Ophthalmology, University of Würzburg, Würzburg, Germany
| | - Jost Hillenkamp
- Department of Ophthalmology, University of Würzburg, Würzburg, Germany
| | - Frank Puppe
- Institute for Artificial Intelligence and Knowledge Systems, Department of Informatics, University of Würzburg, Würzburg, Germany
| | - Nils A Loewen
- Department of Ophthalmology, University of Würzburg, Würzburg, Germany.,Artemis Eye Centers, Frankfurt, Germany
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Comparison of Two Tonometers in the Evaluation of 24-Hour Intraocular Pressure and Mean Ocular Perfusion Pressure in Patients with Thyroid-Associated Ophthalmopathy. J Ophthalmol 2022; 2022:8628362. [PMID: 35496771 PMCID: PMC9054469 DOI: 10.1155/2022/8628362] [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: 10/28/2021] [Revised: 02/28/2022] [Accepted: 03/31/2022] [Indexed: 12/01/2022] Open
Abstract
Purpose The aim of the study is to compare a non-contact tonometer (NCT) and goldmann applannation tonometer (GAT) in the evaluation of intraocular pressure (IOP) and mean ocular perfusion pressure (MOPP) in patients with thyroid-associated ophthalmopathy (TAO). Methods In this study, a total of 30 patients (16 females and 14 males) were recruited. All patients underwent a routine ophthalmic assessment and their medical history was acquired. Clinical assessment included the 24-hour measurement of intraocular pressure and blood pressure, an orbital computed tomography (CT) scan, and a visual field (VF)test. Patients were divided into two groups according to their visual field test results: a defect group with mean deviation (MD) of visual field −2 dB or lower and a normal group with MD over −2 dB. Results Bland–Altman's analysis showed similar results of IOP at every time point and revealed an agreement of mean IOP between the two tonometers (the deviation in the mean IOP between the two tonometers was 1 mmHg, with 95% limits of agreement of 8.8 to −6.8 mmHg). The 24-hour MOPP SD value in NCT (2.28) and GAT (1.77) showed that the two instruments had the same diagnostic efficacy (100% sensitivity, 95.8% specificity). The areas under the receiver operator characteristic (ROC) curve of the 24-hour mean ocular perfusion pressure (MOPP) SD (GAT: 0.778, NCT: 0.713; z = 0.669, P=0.504), 24-hour MOPP fluctuation (GAT:0.683, NCT:0.757; z = 0.963, P=0.336) measured by GAT and NCT had no significant difference between the two tonometers. Conclusions The measurement of IOPs, MOPPs, and their diagnostic efficacy of visual field defect showed consistency between NCT and GAT. The study highlights the importance of monitoring the 24-hour MOPP and IOP in TAO patients. Furthermore, it suggests that the less invasive NCT can replace GAT as a long-term monitoring device in TAO patients.
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Liu C, Li Y, Wang M, Li J, Wang N, Zhang F. Changes in intraocular pressure and ocular pulse amplitude of rhesus macaques after blue light scleral cross-linking. BMC Ophthalmol 2022; 22:87. [PMID: 35193527 PMCID: PMC8864789 DOI: 10.1186/s12886-022-02306-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 02/08/2022] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Scleral cross-linking can enhance the biomechanical strength of the sclera and is expected to be a new operative method for the prevention of myopia. However, studies investigating the changes in intraocular pressure (IOP) and ocular pulse amplitude (OPA) after blue light-riboflavin induced scleral collagen cross-linking (SXL) in rhesus monkeys are limited. This study aimed to investigate the changes in IOP and OPA in three-year-old rhesus macaques 1 week, 1 month, and 3 months after blue light-riboflavin SXL. METHODS Seven three-year-old rhesus macaques (14 eyes) were randomly divided into two groups, with 4 monkeys in group A (8 eyes) and 3 monkeys in group B (6 eyes). The right eye of each rhesus macaque was used as the experimental eye, whereas the left eye was used as the control. In group A, one quadrant of each right eye was irradiated. In group B, two quadrants of each right eye and one quadrant of each left eye were irradiated. The IOP and OPA of both eyes were measured in all seven rhesus macaques before SXL and 1 week, 1 month, and 3 months postoperatively, and differences in the IOP and OPA between the experimental and control eyes were evaluated via the paired t test. RESULTS In groups A and B, there were no significant differences between the experimental and control eyes in the IOP or OPA before SXL or 1 week, 1 month, or 3 months postoperatively (P > 0.05). CONCLUSIONS The IOP and OPA are not significantly affected in 1 vs 0 or in 1 vs 2 quadrants of blue light SXL.
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Affiliation(s)
- Chong Liu
- Beijing Ophthalmology & Visual Sciences Key Lab, Beijing Tongren Eye Centre, Beijing Tongren Hospital, Capital Medical University, No. 1 Dongjiaomin Xiang, Beijing, 100730 Dongcheng District China
| | - Yu Li
- Beijing Ophthalmology & Visual Sciences Key Lab, Beijing Tongren Eye Centre, Beijing Tongren Hospital, Capital Medical University, No. 1 Dongjiaomin Xiang, Beijing, 100730 Dongcheng District China
| | - Mengmeng Wang
- Hebei Ophthalmology Key Lab, Hebei Provincial Eye Hospital, Xingtai, Hebei Province China
| | - Jing Li
- Beijing Ophthalmology & Visual Sciences Key Lab, Beijing Tongren Eye Centre, Beijing Tongren Hospital, Capital Medical University, No. 1 Dongjiaomin Xiang, Beijing, 100730 Dongcheng District China
| | - Ningli Wang
- Beijing Ophthalmology & Visual Sciences Key Lab, Beijing Tongren Eye Centre, Beijing Tongren Hospital, Capital Medical University, No. 1 Dongjiaomin Xiang, Beijing, 100730 Dongcheng District China
| | - Fengju Zhang
- Beijing Ophthalmology & Visual Sciences Key Lab, Beijing Tongren Eye Centre, Beijing Tongren Hospital, Capital Medical University, No. 1 Dongjiaomin Xiang, Beijing, 100730 Dongcheng District China
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Belkin A, Dar N, Pillar S, Tempelhof OF, Barkana Y, Sheiman V, Naftali Ben Haim L, Geffen N. The effect of trabeculectomy and glaucoma drainage device implantation on postural intraocular pressure changes in glaucomatous eyes. Acta Ophthalmol 2021; 99:e1112-e1117. [PMID: 33555632 DOI: 10.1111/aos.14776] [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: 07/02/2020] [Accepted: 01/12/2021] [Indexed: 12/01/2022]
Abstract
PURPOSE To investigate the effect of trabeculectomy and glaucoma drainage device implantation on posture related intraocular pressure (IOP) changes in glaucomatous eyes. METHODS Eyes in this prospective study were divided into three groups: those that underwent Ahmed glaucoma valve implantation (Ahmed group), those that underwent trabeculectomy with mitomycin C (trabeculectomy group) and those treated medically (medication group). IOP was measured in the sitting position, and after 15 min in the left lateral decubitus position using a Tonopen XL, and a Goldmann applanation tonometer (GAT). For GAT measurements in the left lateral decubitus position, we used a specialized system comprised of a motorized bed attached to a modified slit-lamp table. RESULTS 111 eyes of 64 glaucoma patients were included in the analysis: 19 in the Ahmed group, 46 in the trabeculectomy group and 46 in the medication group. The difference in IOP between the sitting and supine positions was significant in the medication (2.23 mmHg) and trabeculectomy (1.48 mmHg) groups, but not in the Ahmed group (0.53 mmHg). This significance was reached with the GAT, but not with the Tonopen. A rise of 5 mmHg or more between the sitting and supine positions was documented in 5.2%, 4.3% and 15.2% of eyes in the Ahmed, trabeculectomy and medication groups, respectively. Intraclass correlation coefficient for IOP measurements in the supine position demonstrated good correlation between the two tonometers. CONCLUSIONS Ahmed valve surgery significantly reduces postural IOP response as compared with medically treated controls. There was no significant difference between Ahmed valve and trabeculectomy in terms of their effect on the postural IOP change.
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Affiliation(s)
- Avner Belkin
- Department of Ophthalmology Meir Medical Center Kfar Saba Israel
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
| | - Nimrod Dar
- Department of Ophthalmology Meir Medical Center Kfar Saba Israel
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
| | - Shani Pillar
- Department of Ophthalmology Meir Medical Center Kfar Saba Israel
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
| | - Ortal F. Tempelhof
- Department of Ophthalmology Tel Aviv Sourasky Medical Center Sackler Faculty of Medicine Tel Aviv University Tel Aviv Israel
| | | | | | - Liron Naftali Ben Haim
- Department of Ophthalmology Meir Medical Center Kfar Saba Israel
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
| | - Noa Geffen
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
- Department of Ophthalmology Rabin Medical CenterPetach Tikva Israel
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Uzlu D, Akyol N, Türk A, Gürsoy N, Somuncu AM, Oruç Y. Effect of Body Position on Intraocular Pressure Measured by Rebound Tonometer in Healthy Children. Turk J Ophthalmol 2021; 50:271-274. [PMID: 33342193 PMCID: PMC7610053 DOI: 10.4274/tjo.galenos.2020.57702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Objectives: To evaluate the effect of body position on intraocular pressure (IOP) measurement in the pediatric age group. Materials and Methods: Children whose general condition was healthy and ophthalmic examination was within normal limits were included. Forty-nine eyes of 49 pediatric patients were included in the study. IOP was measured with an ICARE rebound tonometer (ICARE PRO; ICARE, Helsinki, Finland) while patients were in standing, sitting, and supine positions. Differences between the consecutive measurements were compared statistically. Results: Twenty-two of the 49 patients were female, 27 were male. The mean age was 9.61±2.66 (5-15) years. Mean IOP values in the standing, sitting, and supine positions were 18.81±2.97 (11.6-26.2) mmHg, 18.88±3.44, (12-28.2) mmHg, and 19.01±2.8 (13.5-25.9) mmHg, respectively. There were no statistically significant differences in pairwise comparisons of the measurements taken in the different positions (p=0.846, p=0.751, p=0.606). There was a statistically significant correlation between corneal thickness and intraocular pressure values in all measurements (p=0.001, r=0.516). Conclusion: IOP values measured with the ICARE rebound tonometer in healthy children are not affected by body position.
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Affiliation(s)
- Dilek Uzlu
- Karadeniz Technical University Faculty of Medicine, Department of Ophthalmology, Trabzon, Turkey
| | - Nurettin Akyol
- Karadeniz Technical University Faculty of Medicine, Department of Ophthalmology, Trabzon, Turkey
| | - Adem Türk
- Karadeniz Technical University Faculty of Medicine, Department of Ophthalmology, Trabzon, Turkey
| | - Nurcan Gürsoy
- Karadeniz Technical University Faculty of Medicine, Department of Ophthalmology, Trabzon, Turkey
| | - Ahmet Mehmet Somuncu
- Karadeniz Technical University Faculty of Medicine, Department of Ophthalmology, Trabzon, Turkey
| | - Yavuz Oruç
- University of Health Sciences Turkey, Fethi Sekin City Hospital, Clinic of Ophthalmology, Elazığ, Turkey
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Dalal SR, Ramachandran V, Khalid R, Keith Manuel F, Knowles JR, Jones JA. Increased Intraocular Pressure in Glaucomatous, Ocular Hypertensive, and Normotensive Space Shuttle Crew. Aerosp Med Hum Perform 2021; 92:728-733. [PMID: 34645553 DOI: 10.3357/amhp.5455.2021] [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: 11/24/2022]
Abstract
BACKGROUND: Glaucoma and ocular hypertension (OHT) are prevalent diseases with baseline intraocular pressure (IOP) elevations that future astronauts and spaceflight participants may suffer from. Preflight, in-flight, and postflight IOP measurements were collected aboard two U.S. Space Shuttle Program missions in normotensive control, OHT, and glaucomatous crewmembers. METHODS: Five subjects (three controls, one glaucomatous, one OHT) were studied aboard 2-wk Space Shuttle missions. Baseline IOP (triplicate; handheld tonometry) was recorded during training 12 mo preflight, in flight (114 d), and postflight (329 d). Subjective symptoms were recorded via questionnaires. Data were analyzed using a spreadsheet with two-sample t-tests. P-value < 0.05 determined significance. RESULTS: IOP increased for all in-flight vs. preflight measurements for controls (N 3, 48.9, 16.9, 5.85), OHT (N 1, 20.3), and glaucomatous (N 1, 32.2) groups. IOP eventually returned to baseline postflight [Return (R)35 d], except for the astronaut with OHT (R917). Subjective symptoms, likely multifactorial, included blurredvision, decreased visual acuity, and headaches. DISCUSSION: IOP increased during spaceflight and normalized upon return. Astronauts and commercial spaceflight participants may need screening for elevated IOP to potentially prevent sequelae related to glaucoma and OHT, the former which requires treatment in flight and the latter which may need prophylaxis. Previous studies have shown elevated IOP upon entry into microgravity with various normalization timeframes in flight and postflight. It is unclear how increased IOP relates to spaceflight-associated neuro-ocular syndrome (SANS); however, several hypotheses exist. Treatment strategies should be available for acute and chronic ocular pathology during spaceflight despite the unique challenges of eye-drop application in microgravity. Dalal SR, Ramachandran V, Khalid R, Manuel FK, Knowles JR, Jones JA. Increased intraocular pressure in glaucomatous, ocular hypertensive, and normotensive space shuttle crew. Aerosp Med Hum Perform. 2021; 92(9):728733.
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Greenwald SH, Macias BR, Lee SMC, Marshall-Goebel K, Ebert DJ, Liu JHK, Ploutz-Snyder RJ, Alferova IV, Dulchavsky SA, Hargens AR, Stenger MB, Laurie SS. Intraocular pressure and choroidal thickness respond differently to lower body negative pressure during spaceflight. J Appl Physiol (1985) 2021; 131:613-620. [PMID: 34166098 DOI: 10.1152/japplphysiol.01040.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Spaceflight-associated neuro-ocular syndrome (SANS) develops during long-duration (>1 mo) spaceflight presumably because of chronic exposure to a headward fluid shift that occurs in weightlessness. We aimed to determine whether reversing this headward fluid shift with acute application of lower body negative pressure (LBNP) can influence outcome measures at the eye. Intraocular pressure (IOP) and subfoveal choroidal thickness were therefore evaluated by tonometry and optical coherence tomography (OCT), respectively, in 14 International Space Station crewmembers before flight in the seated, supine, and 15° head-down tilt (HDT) postures and during spaceflight, without and with application of 25 mmHg LBNP. IOP in the preflight seated posture was 14.4 mmHg (95% CI, 13.5-15.2 mmHg), and spaceflight elevated this value by 1.3 mmHg (95% CI, 0.7-1.8 mmHg, P < 0.001). Acute exposure to LBNP during spaceflight reduced IOP to 14.2 mmHg (95% CI, 13.4-15.0 mmHg), which was equivalent to that of the seated posture (P > 0.99), indicating that venous fluid redistribution by LBNP can influence ocular outcome variables during spaceflight. Choroidal thickness during spaceflight (374 µm, 95% CI, 325-423 µm) increased by 35 µm (95% CI, 25-45 µm, P < 0.001), compared with the preflight seated posture (339 µm, 95% CI, 289-388 µm). Acute use of LBNP during spaceflight did not affect choroidal thickness (381 µm, 95% CI, 331-430 µm, P = 0.99). The finding that transmission of reduced venous pressure by LBNP did not decrease choroidal thickness suggests that engorgement of this tissue during spaceflight may reflect changes that are secondary to the chronic cerebral venous congestion associated with spaceflight.NEW & NOTEWORTHY Spaceflight induces a chronic headward fluid shift that is believed to underlie ocular changes observed in astronauts. The present study demonstrates, for the first time, that reversing this headward fluid shift via application of lower body negative pressure (LBNP) during spaceflight may alter the ocular venous system, as evidenced by a decrease in intraocular pressure. This finding indicates that LBNP has the potential to be an effective countermeasure against the headward fluid shift during spaceflight, which may then be beneficial in preventing or reversing associated ocular changes.
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Affiliation(s)
| | - Brandon R Macias
- National Aeronautics and Space Administration, Johnson Space Center, Houston, Texas
| | | | | | | | - John H K Liu
- Shiley Eye Institute, University of California, San Diego, California
| | - Robert J Ploutz-Snyder
- Applied Biostatistics Laboratory, School of Nursing, University of Michigan, Ann Arbor, Michigan
| | - Irina V Alferova
- Russian Federation State Research Center Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia
| | | | - Alan R Hargens
- Altman Clinical and Translational Research Institute, University of California, San Diego, California
| | - Michael B Stenger
- National Aeronautics and Space Administration, Johnson Space Center, Houston, Texas
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12
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Belkin A, Greene RA, Mathew DJ, Trope GE, Jin YP, Gentili F, Buys YM. Postural Changes and the Trans-Lamina Cribrosa Pressure Difference: A Pilot Study in Neurosurgical Patients without Glaucoma. Ophthalmol Glaucoma 2020; 3:269-273. [PMID: 33008559 DOI: 10.1016/j.ogla.2020.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 02/26/2020] [Accepted: 02/27/2020] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the effect of changes in position in the trans-lamina cribrosa pressure difference (TLCPD) by simultaneously measuring and comparing intracranial pressure (ICP) with intraocular pressure (IOP) in seated and supine positions. DESIGN Prospective cohort study. PARTICIPANTS Patients admitted to the neurosurgery unit at Toronto Western Hospital with an external ventricular drain placed for ICP monitoring. Exclusion criteria were any ophthalmic surgical procedures within the preceding 6 months, history of glaucoma, and corneal abnormalities affecting IOP measurement. METHODS Intraocular pressure and ICP were recorded simultaneously in both the supine and seated positions with the order of positions randomized. Measurements were made 10 minutes after assuming each position. The TLCPD (IOP minus ICP) was calculated for the sitting and supine positions. The paired t test was used to assess significance of differences. MAIN OUTCOME MEASURE The TLCPD. RESULTS Twenty patients were included in the study. The average age was 54±17 years. Results were similar for left and right eyes. Data are shown for right eyes only. Mean sitting and supine IOPs were 15.3±3.5 mmHg and 15.9±3.7 mmHg, respectively (P = 0.32). Mean sitting and supine ICPs were 12.5±6.8 mmHg and 12.8±5.1 mmHg, respectively (P = 0.66). Mean TLCPD was 3.1±6.0 mmHg in the sitting position and 3.1±7.0 mmHg in the supine position (P = 1.00). Supine TLCPD increased in 10 patients (50%), decreased in 8 patients (40%), and was unchanged in 2 patients (10%). CONCLUSIONS In this pilot study of 20 neurosurgical patients without glaucoma, posture-induced TLCPD changes were variable.
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Affiliation(s)
- Avner Belkin
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada.
| | - Rana A Greene
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
| | - David J Mathew
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
| | - Graham E Trope
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
| | - Ya-Ping Jin
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
| | - Fred Gentili
- Department of Surgery, University of Toronto, Toronto, Canada
| | - Yvonne M Buys
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
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13
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Wu Y, Luttrell I, Feng S, Chen PP, Spaide T, Lee AY, Wen JC. Development and validation of a machine learning, smartphone-based tonometer. Br J Ophthalmol 2019; 104:1394-1398. [PMID: 31871048 DOI: 10.1136/bjophthalmol-2019-315446] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 12/05/2019] [Accepted: 12/10/2019] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS To compare intraocular pressure (IOP) measurements using a prototype smartphone tonometer with other tonometers used in clinical practice. METHODS Patients from an academic glaucoma practice were recruited. The smartphone tonometer uses fixed force applanation and in conjunction with a machine-learning computer algorithm is able to calculate the IOP. IOP was also measured using Goldmann applanation tonometry (GAT) in all subjects. A subset of patients were also measured using ICare, pneumotonometry (upright and supine positions) and Tono-Pen (upright and supine positions) and the results were compared. RESULTS 92 eyes of 81 subjects were successfully measured. The mean difference (in mm Hg) for IOP measurements of the smartphone tonometer versus other devices was +0.24 mm Hg for GAT, -1.39 mm Hg for ICare, -3.71 mm Hg for pneumotonometry and -1.30 mm Hg for Tono-Pen. The 95% limits of agreement for the smartphone tonometer versus other devices was -4.35 to 4.83 mm Hg for GAT, -6.48 to 3.70 mm Hg for ICare, -7.66 to -0.15 mm Hg for pneumotonometry and -5.72 to 3.12 mm Hg for Tono-Pen. Overall, the smartphone tonometer results correlated best with GAT (R2=0.67, p<0.001). Of the 92 videos, 90 (97.8%) were within ±5 mm Hg of GAT and 58 (63.0%) were within ±2 mm Hg of GAT. CONCLUSIONS Preliminary IOP measurements using a prototype smartphone-based tonometer was grossly equivalent to the reference standard.
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Affiliation(s)
- Yue Wu
- Ophthalmology, University of Washington, Seattle, Washington, USA
| | - Ian Luttrell
- Ophthalmology, University of Washington, Seattle, Washington, USA
| | - Shu Feng
- University of Washington, Seattle, Washington, USA
| | | | - Ted Spaide
- University of Washington, Seattle, Washington, USA
| | - Aaron Y Lee
- University of Washington, Seattle, Washington, USA
| | - Joanne C Wen
- Ophthalmology, Duke University, Durham, North Carolina, USA
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Otsuka M, Tojo N, Hayashi A. Error in measurement of intraocular pressure with the Icare and IcarePRO. Int Ophthalmol 2019; 40:439-445. [PMID: 31691898 DOI: 10.1007/s10792-019-01204-7] [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: 06/10/2019] [Accepted: 10/22/2019] [Indexed: 11/29/2022]
Abstract
PURPOSE We sought to determine whether changes in the measurement angle of the Icare TA01i and IcarePRO tonometers led to errors in the measurement of intraocular pressure (IOP). METHODS In this prospective, single-facility study, we analyzed 77 patients from November 2017 to September 2019. We measured IOP with the Icare TA01i and IcarePRO while changing the angle of the device with the cornea center and analyzed the associated changes in the measurement. RESULTS IOP measured with the Icare tilted - 30°, - 15° vertically was significantly higher than that measured with the Icare tilted horizontally (p < 0.0001, p < 0.0001). The IOP measured with a + 10° vertical tilt was significantly lower than that measured horizontally (p < 0.0001). When the IcarePRO was tilted + 90° vertically, the IOP was significantly lower with the patient in the supine position than in the lateral position (p = 0.00058). CONCLUSIONS IOP measured with the Icare and IcarePRO is affected by the measurement angle. The study results will direct the clinicians to exercise extra precautions in determining the measurement angle while measuring IOP.
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Affiliation(s)
- Mitsuya Otsuka
- Department of Ophthalmology and Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
| | - Naoki Tojo
- Department of Ophthalmology and Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Atsushi Hayashi
- Department of Ophthalmology and Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
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Intraocular Pressure Measurements in Standing Position with a Rebound Tonometer. ACTA ACUST UNITED AC 2019; 55:medicina55100701. [PMID: 31635406 PMCID: PMC6843247 DOI: 10.3390/medicina55100701] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/14/2019] [Accepted: 10/16/2019] [Indexed: 11/16/2022]
Abstract
Background and Objectives: It has been established that body position can play an important role in intraocular pressure (IOP) fluctuation. IOP has been previously shown to increase significantly when lying down, relative to sitting; this type of investigation has not been extensively reported for the standing (ST) position. Therefore, this study aims to look for eventual significant IOP changes while ST, sitting, and lying down. Materials and Methods: An Icare PRO was used to measure the IOP of 120 eyes of 60 healthy individuals, with age ranging from 21 to 55 years (mean 29.22 ± 9.12 years), in sitting, supine and ST positions; IOP was measured again, 5 min after standing (ST-5m). Results: Mean IOP difference between sitting and ST position was 0.39 ± 1.93 mmHg (95% CI: 0.04 to 0.74 mmHg) (p = 0.027); between sitting and ST-5m, it was −0.48 ± 1.79 mmHg (95% CI: −0.8 to −0.16 mmHg) (p = 0.004); between the sitting and supine position, it was −1.16±1.9 mmHg (95% CI: −1.5 to −0.82 mmHg) (p < 0.001); between the supine and ST position, it was 1.55 ± 2.04 mmHg (95% CI: 1.18 to 1.92 mmHg) (p < 0.001); between supine and ST-5m, it was 0.68 ± 1.87 mmHg (95% CI: 0.34 to 1.02 mmHg) (p < 0.001); and between ST-5m and ST, it was 0.94 ± 1.95 mmHg (95% CI: 0.58 to 1.29 mmHg) (p < 0.001). Mean axial eye length was 24.45 mm (95% CI: 24.22 to 24.69 mm), and mean central corneal thickness was 535.30 μm (95% CI: 529.44 to 541.19 μm). Conclusion: Increased IOP in the ST-5m position suggests that IOP measurements should be performed in this position too. The detection of higher IOP values in the ST-5m position than in the sitting one, may explain the presence of glaucoma damage or progression in apparently normal-tension or compensated patients.
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16
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Mayalı H, Tekin B, Kayıkçıoğlu ÖR, Kurt E, İlker SS. Evaluation of the Effect of Body Position on Intraocular Pressure Measured with Rebound Tonometer. Turk J Ophthalmol 2019; 49:6-9. [PMID: 30829018 PMCID: PMC6416475 DOI: 10.4274/tjo.galenos.2018.90359] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Objectives: It is important to determine variables that influence intraocular pressure (IOP) measurement. This study aimed to evaluate the effect of body position on IOP. Materials and Methods: The study included 52 right eyes of 52 patients who presented to the ophthalmology department of our hospital and had no ocular disease except refractive errors. IOP was measured with an Icare PRO tonometer while patients were in sitting, standing, and supine positions, with intervals of 10 minutes between the positions. Correlations between the results were evaluated using Spearman’s correlation analysis and Wilcoxon tests. Results: Thirty-six of the 52 patients were female, 16 were male. Mean age was 31.65±6.30 (23-47) years. Mean IOP values in the sitting, standing, and lying positions were 17.76±3.41 (12.70-25.60) mmHg, 17.10±3.27 (11.50-25.20) mmHg, and 18.46±4.67 (10.50-29.40) mmHg, respectively. There were no statistically significant differences between measurements taken in the different positions (p=0.112, p=0.472, p=0.071). We observed that there was no relationship between age and body position (p>0.45, p>0.79, p>0.77) or between gender and position (p>0.59, p>0.69, p>0.54). Conclusion: Gender and age had no effect on IOP measured in different body positions. There were also no significant differences between IOP values measured in the different positions. Therefore, we believe the portable Icare PRO tonometer can be used for patients who are confined to bed and will provide IOP measurements that are concordant with values obtained while sitting.
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Affiliation(s)
- Hüseyin Mayalı
- Manisa Celal Bayar University Faculty of Medicine, Department of Ophthalmology, Manisa, Turkey
| | - Beyza Tekin
- Manisa Celal Bayar University Faculty of Medicine, Department of Ophthalmology, Manisa, Turkey
| | - Özcan Rasim Kayıkçıoğlu
- Manisa Celal Bayar University Faculty of Medicine, Department of Ophthalmology, Manisa, Turkey
| | - Emin Kurt
- Manisa Celal Bayar University Faculty of Medicine, Department of Ophthalmology, Manisa, Turkey
| | - Süleyman Sami İlker
- Manisa Celal Bayar University Faculty of Medicine, Department of Ophthalmology, Manisa, Turkey
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17
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Snyder KC, Lewin AC, Mans C, McLellan GJ. Tonometer validation and intraocular pressure reference values in the normal chinchilla (Chinchilla lanigera). Vet Ophthalmol 2017; 21:4-9. [PMID: 28303681 DOI: 10.1111/vop.12468] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To determine accuracy and precision of three commonly used tonometers (TonoVet® and TonoLab® (ICare Oy, Finland)-rebound tonometers, and Tono-Pen VET™ (Reichert, NY)-applanation tonometer) in normal chinchillas, and to establish a normal intraocular pressure (IOP) reference range in this species. METHODS The anterior chambers of three chinchilla eyes were cannulated ex vivo and readings obtained at manometric IOPs from 5 to 80 mmHg, using each of the three tonometers in random order. Data were analyzed by linear regression, ANOVA, and Bland-Altman plots. Tonometry was performed in both eyes of 60 chinchillas (age 8 weeks-16.2 years) using the TonoVet® and relationship between age and IOP analyzed using linear regression. For all statistical tests, P < 0.05 was significant. RESULTS Intraocular pressure values obtained using the Tono-Pen VET™ and TonoVet® (in dog calibration mode;'d') showed strong linear correlation with manometry within the physiologic and clinically relevant range of IOP (0-50 mmHg). The TonoVet® 'd' setting displayed significantly greater precision over the full range of IOP evaluated than the Tono-Pen VET™, and both TonoVet and Tono-Pen VET™ were significantly more accurate than the TonoLab® tonometer. Mean ± SD IOP (TonoVet® 'd') in chinchillas was 9.7 ± 2.5 mmHg, and the 95% reference interval was 4.7-14.7 mmHg. CONCLUSIONS Both the Tono-Pen VET™ and TonoVet® provided clinically acceptable estimates of IOP in chinchillas. The TonoVet® provides accurate and precise IOP values, while Tono-Pen VET™ derived measurements showed greater variability. Values obtained either with the TonoLab® or TonoVet® used in the 'unspecified' calibration setting were inaccurate in this species.
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Affiliation(s)
- Kevin C Snyder
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin - Madison, Madison, WI, 53792, USA.,McPherson Eye Research Institute, University of Wisconsin - Madison, Madison, WI, 53792, USA
| | - Andrew C Lewin
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin - Madison, Madison, WI, 53792, USA.,McPherson Eye Research Institute, University of Wisconsin - Madison, Madison, WI, 53792, USA
| | - Christoph Mans
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin - Madison, Madison, WI, 53792, USA
| | - Gillian J McLellan
- Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin - Madison, Madison, WI, 53792, USA.,McPherson Eye Research Institute, University of Wisconsin - Madison, Madison, WI, 53792, USA.,Department of Ophthalmology & Visual Sciences, University of Wisconsin - Madison, Madison, WI, 53792, USA
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18
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Nabeta HW, Bahr NC, Rhein J, Fossland N, Kiragga AN, Meya DB, Dunlop SJ, Boulware DR. Accuracy of noninvasive intraocular pressure or optic nerve sheath diameter measurements for predicting elevated intracranial pressure in cryptococcal meningitis. Open Forum Infect Dis 2014; 1:ofu093. [PMID: 25734161 PMCID: PMC4324219 DOI: 10.1093/ofid/ofu093] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 09/11/2014] [Indexed: 11/21/2022] Open
Abstract
Intraocular pressure measurement by tonometry and optic nerve sheath diameter measurement by ultrasound have imprecise but statistical correlation with intracranial pressure. Neither technique is an effective surrogate measure of intracranial pressure in cryptococcal meningitis; manometry should be used. Background Cryptococcal meningitis is associated with increased intracranial pressure (ICP). Therapeutic lumbar puncture (LP) is recommended when the initial ICP is >250 mm H2O, yet the availability of manometers in Africa is limited and not always used where available. We assessed whether intraocular pressure could be a noninvasive surrogate predictor to determine when additional therapeutic LPs are necessary. Methods Ninety-eight human immunodeficiency virus-infected Ugandans with suspected meningitis (81% Cryptococcus) had intraocular pressure measured using a handheld tonometer (n = 78) or optic nerve sheath diameter (ONSD) measured by ultrasound (n = 81). We determined the diagnostic performance of these methods for predicting ICP vs a standard manometer. Results The median ICP was 225 mm H2O (interquartile range [IQR], 135–405 mm H2O). The median intraocular pressure was 28 mm Hg (IQR, 22–37 mm Hg), and median ultrasound ONSD was 5.4 mm (IQR, 4.95–6.1 mm). ICP moderately correlated with intraocular pressure (ρ = 0.45, P < .001) and with ultrasound ONSD (ρ = 0.44, P < .001). There were not discrete threshold cutoff values for either tonometry or ultrasound ONSD that provided a suitable cutoff diagnostic value to predict elevated ICP (>200 mm H2O). However, risk of elevated ICP >200 mm H2O was increased with an average intraocular pressure >28 mm Hg (relative risk [RR] = 3.03; 95% confidence interval [CI], 1.55–5.92; P < .001) or an average of ONSD >5 mm (RR = 2.39; 95% CI, 1.42–4.03; P = .003). As either intraocular pressure or ONSD increased, probability of elevated ICP increased (ie, positive predictive value increased). Conclusions Noninvasive intraocular pressure measurements by tonometry or ultrasound correlate with cerebrospinal fluid opening pressure, but both are a suboptimal replacement for actual ICP measurement with a manometer.
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Affiliation(s)
- Henry W Nabeta
- Infectious Diseases Institute , Makerere University , Kampala , Uganda
| | - Nathan C Bahr
- Infectious Diseases Institute , Makerere University , Kampala , Uganda ; Department of Medicine ; Center for Infectious Disease and Microbiology Translational Research
| | - Joshua Rhein
- Infectious Diseases Institute , Makerere University , Kampala , Uganda ; Department of Medicine ; Center for Infectious Disease and Microbiology Translational Research
| | | | - Agnes N Kiragga
- Infectious Diseases Institute , Makerere University , Kampala , Uganda
| | - David B Meya
- Infectious Diseases Institute , Makerere University , Kampala , Uganda ; Department of Medicine ; Center for Infectious Disease and Microbiology Translational Research
| | - Stephen J Dunlop
- Department of Emergency Medicine , Hennepin County Medical Center ; Department of Emergency Medicine, University of Minnesota , Minneapolis, Minnesota
| | - David R Boulware
- Department of Medicine ; Center for Infectious Disease and Microbiology Translational Research
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