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Hamarat Y, Bartusis L, Putnynaite V, Zakelis R, Deimantavicius M, Zigmantaite V, Grigaleviciute R, Kucinskas A, Kalvaitis E, Ragauskas A. Intraorbital pressure-volume characteristics in a piglet model: In vivo pilot study. PLoS One 2024; 19:e0296780. [PMID: 38215081 PMCID: PMC10786399 DOI: 10.1371/journal.pone.0296780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 12/19/2023] [Indexed: 01/14/2024] Open
Abstract
Intracranial pressure measurement is frequently used for diagnosis in neurocritical care but cannot always accurately predict neurological deterioration. Intracranial compliance plays a significant role in maintaining cerebral blood flow, cerebral perfusion pressure, and intracranial pressure. This study's objective was to investigate the feasibility of transferring external pressure into the eye orbit in a large-animal model while maintaining a clinically acceptable pressure gradient between intraorbital and external pressures. The experimental system comprised a specifically designed pressure applicator that can be placed and tightly fastened onto the eye. A pressure chamber made from thin, elastic, non-allergenic film was attached to the lower part of the applicator and placed in contact with the eyelid and surrounding tissues of piglets' eyeballs. External pressure was increased from 0 to 20 mmHg with steps of 1 mmHg, from 20 to 30 mmHg with steps of 2 mmHg, and from 30 to 50 mmHg with steps of 5 mmHg. An invasive pressure sensor was used to measure intraorbital pressure directly. An equation was derived from measured intraorbital and external pressures (intraorbital pressure = 0.82 × external pressure + 3.12) and demonstrated that external pressure can be linearly transferred to orbit tissues with a bias (systematic error) of 3.12 mmHg. This is close to the initial intraorbital pressure within the range of pressures tested. We determined the relationship between intraorbital compliance and externally applied pressure. Our findings indicate that intraorbital compliance can be controlled across a wide range of 1.55 to 0.15 ml/mmHg. We observed that external pressure transfer into the orbit can be achieved while maintaining a clinically acceptable pressure gradient between intraorbital and external pressures.
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Affiliation(s)
- Yasin Hamarat
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
| | - Laimonas Bartusis
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
| | - Vilma Putnynaite
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
| | - Rolandas Zakelis
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
| | - Mantas Deimantavicius
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
| | - Vilma Zigmantaite
- Biological Research Center, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Ramunė Grigaleviciute
- Biological Research Center, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Audrius Kucinskas
- Biological Research Center, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Evaldas Kalvaitis
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
| | - Arminas Ragauskas
- Health Telematics Science Institute, Kaunas University of Technology, Kaunas, Lithuania
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Sayah DN, Lesk MR. Ocular Rigidity and Current Therapy. Curr Eye Res 2023; 48:105-113. [PMID: 35763027 DOI: 10.1080/02713683.2022.2093380] [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: 02/08/2023]
Abstract
Purpose: Ocular rigidity (OR) is an important biomechanical parameter of the eye accounting for the material and geometrical properties of the corneoscleral shell.Methods: This study used a literature search to review the role of ocular rigidity and the application of potential therapies targeting this parameter in glaucoma and myopia.Conclusion: Biomechanical modeling and improved understanding of the biochemistry, and molecular arrangement of sclera and its constituents have yielded important insights. Recent developments, including that of a non-invasive and direct OR measurement method and improved ocular imaging techniques are helping to elucidate the role of OR in healthy and diseased eyes by facilitating large scale and longitudinal clinical studies. Improved understanding of OR at the initial stages of disease processes and its alterations with disease progression will undoubtedly propel research in the field. Furthermore, a better understanding of the determinants of OR is helping to refine novel therapeutic approaches which target and alter the biomechanical properties of the sclera in sight-threatening conditions such as glaucoma and myopia.
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Affiliation(s)
- Diane N Sayah
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Canada.,School of Optometry, Université de Montréal, Montreal, Canada
| | - Mark R Lesk
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Canada.,Department of Ophthalmology, Faculty of Medicine, Université de Montréal, Montreal, Canada.,Centre Universitaire d'ophtalmologie de l'Université de Montréal de l'Hôpital Maisonneuve-Rosemont, CIUSSS-E, Montreal, Canada
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3
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Zhang J, Kim K, Kim HJ, Meyer D, Park W, Lee SA, Dai Y, Kim B, Moon H, Shah JV, Harris KE, Collar B, Liu K, Irazoqui P, Lee H, Park SA, Kollbaum PS, Boudouris BW, Lee CH. Smart soft contact lenses for continuous 24-hour monitoring of intraocular pressure in glaucoma care. Nat Commun 2022; 13:5518. [PMID: 36127347 PMCID: PMC9489713 DOI: 10.1038/s41467-022-33254-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 09/09/2022] [Indexed: 11/09/2022] Open
Abstract
Continuous monitoring of intraocular pressure, particularly during sleep, remains a grand challenge in glaucoma care. Here we introduce a class of smart soft contact lenses, enabling the continuous 24-hour monitoring of intraocular pressure, even during sleep. Uniquely, the smart soft contact lenses are built upon various commercial brands of soft contact lenses without altering their intrinsic properties such as lens power, biocompatibility, softness, transparency, wettability, oxygen transmissibility, and overnight wearability. We show that the smart soft contact lenses can seamlessly fit across different corneal curvatures and thicknesses in human eyes and therefore accurately measure absolute intraocular pressure under ambulatory conditions. We perform a comprehensive set of in vivo evaluations in rabbit, dog, and human eyes from normal to hypertension to confirm the superior measurement accuracy, within-subject repeatability, and user comfort of the smart soft contact lenses beyond current wearable ocular tonometers. We envision that the smart soft contact lenses will be effective in glaucoma care.
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Affiliation(s)
- Jinyuan Zhang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Kyunghun Kim
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Ho Joong Kim
- Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, USA
| | - Dawn Meyer
- School of Optometry, Indiana University, Bloomington, IN, USA
| | - Woohyun Park
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Seul Ah Lee
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Yumin Dai
- School of Materials Engineering, Purdue University, West Lafayette, IN, USA
| | - Bongjoong Kim
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.,Department of Mechanical and System Design Engineering, Hongik University, Seoul, 04066, Republic of Korea
| | - Haesoo Moon
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Jay V Shah
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA
| | - Keely E Harris
- Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN, USA
| | - Brett Collar
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Kangying Liu
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Pedro Irazoqui
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Hyowon Lee
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.,Center for Implantable Devices, Purdue University, West Lafayette, IN, USA.,Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - Shin Ae Park
- Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN, USA.
| | - Pete S Kollbaum
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA. .,School of Optometry, Indiana University, Bloomington, IN, USA.
| | - Bryan W Boudouris
- Charles D. Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN, USA. .,Department of Chemistry, Purdue University, West Lafayette, IN, USA. .,Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA.
| | - Chi Hwan Lee
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA. .,School of Optometry, Indiana University, Bloomington, IN, USA. .,School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA. .,School of Materials Engineering, Purdue University, West Lafayette, IN, USA. .,Center for Implantable Devices, Purdue University, West Lafayette, IN, USA. .,Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA.
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Bontzos G, Douglas VP, Douglas KAA, Kapsala Z, Drakonaki EE, Detorakis ET. Ultrasound Elastography in Ocular and Periocular Tissues: A Review. Curr Med Imaging 2021; 17:1041-1053. [PMID: 33319691 DOI: 10.2174/1573405616666201214123117] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/31/2020] [Accepted: 10/15/2020] [Indexed: 11/22/2022]
Abstract
Ultrasound elastography has become available in everyday practice, allowing direct measurement of tissue elasticity with important and expanding clinical applications. Several studies that have evaluated pathological and non-pathological tissues have demonstrated that ultrasound elastography can actually improve the diagnostic accuracy of the underlying disease process by detecting differences in their elasticity. Ocular and periocular tissues can also be characterized by their elastic properties. In this context, a comprehensive review of literature on ultrasound elastography as well as its current applications in Ophthalmology is presented.
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Affiliation(s)
- Georgios Bontzos
- Department of Ophthalmology, University Hospital of Heraklion, Crete, Greece
| | | | | | - Zoi Kapsala
- Department of Ophthalmology, University Hospital of Heraklion, Crete, Greece
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[Ocular hypertension and optic neuropathies secondary to dysthyroid orbitopathy: Review of the literature]. J Fr Ophtalmol 2021; 44:1256-1261. [PMID: 34303550 DOI: 10.1016/j.jfo.2021.01.026] [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: 09/14/2020] [Revised: 01/07/2021] [Accepted: 01/10/2021] [Indexed: 11/21/2022]
Abstract
Dysthyroidism, especially Graves' disease, causes potentially severe orbital disease. This is frequently accompanied by ocular hypertension stemming from multiple pathophysiological mechanisms. Adaptations in the technique of intraocular pressure measurement must occur, using portable equipment if necessary. Glaucomatous optic neuropathy secondary to dysthyroid orbitopathy is rare, and screening for signs of compressive optic neuropathy is essential in the case of visual field loss. In cases of secondary glaucomatous optic neuropathy, treatment of the intraocular pressure is based mainly on systemic corticosteroid therapy and topical medications as necessary.
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Sayah DN, Mazzaferri J, Descovich D, Costantino S, Lesk MR. The Association Between Ocular Rigidity and Neuroretinal Damage in Glaucoma. Invest Ophthalmol Vis Sci 2021; 61:11. [PMID: 33151280 PMCID: PMC7671866 DOI: 10.1167/iovs.61.13.11] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Ocular rigidity (OR) is an important biomechanical property, thought to be relevant in the pathophysiology of open-angle glaucoma (OAG). This study aims to evaluate the relationship between OR and neuroretinal damage caused by glaucoma. Methods One hundred eight subjects (22 with healthy eyes, 23 with suspect discs, and 63 with OAG) were included in this study. OR was measured using a noninvasive optical coherence tomography (OCT)-based method developed by our group. We also measured central corneal thickness (CCT), corneal hysteresis (CH), and corneal resistance factor (CRF). Pearson and partial correlations were performed to evaluate the relationship between OR and glaucomatous damage represented by ganglion cell complex (GCC), retinal nerve fiber layer (RNFL) thicknesses, and neuroretinal rim area. Results Significant positive correlations were found between OR and minimum GCC thickness (r = 0.325, P = 0.001), average GCC thickness (r = 0.320, P = 0.002), rim area (r = 0.344, P < 0.001), and RNFL thickness in the superior (r = 0.225, P = 0.023), and inferior (r = 0.281, P = 0.004) quadrants. These correlations were generally greater than those found for CCT, CH, and CRF. Furthermore, no correlation was found between OR and corneal biomechanical parameters. After adjusting for age, sex, and ethnicity, significant correlations were found between OR and minimum and average GCC thickness (r = 0.357, P = 0.001 and r = 0.344, P = 0.001, respectively), rim area (r = 0.327, P = 0.001), average RNFL thickness (r = 0.331, P = 0.001), and RNFL thickness in the superior (r = 0.296, P = 0.003) and inferior (r = 0.317, P = 0.001) quadrants. Conclusions In this study, we found a positive correlation between structural OCT-based parameters and OR, indicating more neuroretinal damage in eyes with lower OR. These findings could provide insight into the pathophysiology of OAG.
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Affiliation(s)
- Diane N Sayah
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada.,Department of Ophthalmology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Javier Mazzaferri
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada
| | - Denise Descovich
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada
| | - Santiago Costantino
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada.,Department of Ophthalmology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada.,Centre Universitaire d'ophtalmologie de l'Université de Montréal de l'Hôpital Maisonneuve-Rosemont, CIUSSS-E, Montreal, Quebec, Canada
| | - Mark R Lesk
- Maisonneuve-Rosemont Hospital Research Center, Montreal, Quebec, Canada.,Department of Ophthalmology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada.,Centre Universitaire d'ophtalmologie de l'Université de Montréal de l'Hôpital Maisonneuve-Rosemont, CIUSSS-E, Montreal, Quebec, Canada
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7
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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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Changes in Scleral Tonometry and Anterior Chamber Angle after Short-term Scleral Lens Wear. Optom Vis Sci 2020; 97:720-725. [DOI: 10.1097/opx.0000000000001568] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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M Kouhani MH, Wu J, Tavakoli A, Weber AJ, Li W. Wireless, passive strain sensor in a doughnut-shaped contact lens for continuous non-invasive self-monitoring of intraocular pressure. LAB ON A CHIP 2020; 20:332-342. [PMID: 31825423 DOI: 10.1039/c9lc00735k] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
After cataract, glaucoma is the second leading cause of blindness worldwide and real-time monitoring of intraocular pressure (IOP) is of great demand. We present a wireless, passive sensor sitting inside a customized, planar and circular doughnut-shaped contact lens capable of continuous monitoring of the change in the curvature of cornea caused by IOP fluctuations. The sensor consists of a constant capacitor and a variable inductor in the form of a stretchable, closed-loop, serpentine wire that serves as both the sensor and the antenna. Results show a pressure responsivity of 523 kHz per 1% axial strain on a pressurized polydimethylsiloxane membrane and 35.1 kHz per 1 mmHg change in the IOP of a canine eye. The sensor is tested for stability and shows unvaried characteristics after repeated cycles and parasitic movements. Predictable influences of temperature and humidity on the sensor response are also verified experimentally, which can be canceled out using real-time calibration with temperature and humidity sensors to integrate with a reader device. The design reported here has numerous advantages, such as design simplicity, component reliability, high responsivity, and low cost, thereby opening up potential opportunities for the translation of this non-invasive, continuous IOP monitoring technique into clinical applications.
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Affiliation(s)
- M Hossein M Kouhani
- Electrical and Computer Engineering Department, Michigan State University, East Lansing, MI, USA.
| | - Jiajia Wu
- Electrical and Computer Engineering Department, Michigan State University, East Lansing, MI, USA.
| | - Arman Tavakoli
- Department of Mathematics, Michigan State University, East Lansing, MI, USA
| | - Arthur J Weber
- Department of Physiology, Michigan State University, East Lansing, MI, USA
| | - Wen Li
- Electrical and Computer Engineering Department, Michigan State University, East Lansing, MI, USA.
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Karyotakis NG, Ginis HS, Dastiridou AI, Tsilimbaris MK, Pallikaris IG. Manometric measurement of the outflow facility in the living human eye and its dependence on intraocular pressure. Acta Ophthalmol 2015; 93:e343-e348. [PMID: 25645503 DOI: 10.1111/aos.12652] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 11/24/2014] [Indexed: 11/30/2022]
Abstract
PURPOSE The intraocular pressure (IOP) is determined by a dynamic equilibrium between the production and outflow of the aqueous humour. The relationship between IOP and the outflow rate through the conventional and unconventional pathway is quantified by the outflow facility coefficient (C). The purpose of this study is to employ a direct (manometric) tonographic technique and determine C as well as its inverse, resistance (R), as a function of IOP in the living human eye. METHODS Nineteen cataract patients were enrolled in the study. An intraoperative manometric device was used to measure IOP. After cannulation of the anterior chamber, the IOP was increased by infusion of controlled amounts of saline solution. At 40 mmHg, the infusion stopped, and a pressure sensor recorded the IOP. The measured pressure-volume relationship was considered in order to convert pressure changes to corresponding ocular volume changes. An appropriate mathematical model was applied to calculate C and (its inverse), R. RESULTS The average C was 0.0672 ± 0.0296 μl/min/mmHg at 40 mmHg and 0.2652 ± 0.1164 μl/min/mmHg at 20 mmHg. There was a strong dependence of coefficient C on IOP in all subjects (p < 0.001). The corresponding values for R were 17.9 ± 11.17 min mmHg/μl at 40 mmHg and 4.51 ± 2.69 min mmHg/μl at 20 mmHg. CONCLUSION This study provides measurement of outflow facility and its dependence with pressure in healthy living human eyes. This relation is shown to be non-linear, using a direct manometric method.
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Affiliation(s)
| | - Harilaos S. Ginis
- Medical School; Institute of Vision and Optics; University of Crete; Heraklion Greece
| | - Anna I. Dastiridou
- Opththalmology Department; University Hospital of Larissa; Larissa Greece
| | - Miltiadis K. Tsilimbaris
- Medical School; Institute of Vision and Optics; University of Crete; Heraklion Greece
- Opththalmology Department; University Hospital of Heraklion; Heraklion Greece
| | - Ioannis G. Pallikaris
- Medical School; Institute of Vision and Optics; University of Crete; Heraklion Greece
- Opththalmology Department; University Hospital of Heraklion; Heraklion Greece
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