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Casanova MI, Young LJ, Park S, Kim S, Roszak K, Leonard BC, Blandino A, Motta MJ, Yiu G, Li JY, Moshiri A, Thomasy SM. Normal Corneal Thickness and Endothelial Cell Density in Rhesus Macaques (Macaca mulatta). Transl Vis Sci Technol 2022; 11:23. [PMID: 36156731 PMCID: PMC9526363 DOI: 10.1167/tvst.11.9.23] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 08/14/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose To define the normal range of central corneal thickness (CCT) and corneal endothelial cell density (ECD) in rhesus macaques (Macaca mulatta) and the effects of age, body weight, sex, and intraocular pressure (IOP) on these parameters. Methods Ophthalmic examinations were performed on 144 rhesus macaques without anterior segment pathology. The CCT was measured via ultrasound pachymetry (USP) and specular microscopy, and the ECD was semiautomatically and manually counted using specular microscopy. Rebound tonometry was used to measure IOP. Linear regression and mixed-effects linear regression models were used to evaluate the effects of age, body weight, sex, and IOP on CCT and ECD. Results We included 98 females and 46 males with an age range of 0.2 to 29.4 years. The mean CCT by USP and specular microscopy were 483 ± 39 and 463 ± 33 µm, respectively, and were statistically different (P < 0.001). The ECDs were 2717 ± 423 and 2747 ± 438 cells/mm2 by semiautomated and manual analysis, respectively. Corneal endothelial degeneration was identified in one aged rhesus macaque. Conclusions The mean USP and specular microscopy CCT values differed significantly, whereas the semiautomatic and manual ECD did not. The CCT was associated with the IOP and sex, whereas the ECD was associated with body weight and age (P < 0.05). As in humans, corneal disease in rhesus macaques is uncommon. Translational Relevance Establishing reference values is fundamental to use rhesus macaques as a model for corneal disease or to identify toxicity in studies of ocular drugs or devices.
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Affiliation(s)
- M. Isabel Casanova
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Laura J. Young
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Sangwan Park
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Soohyun Kim
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Karolina Roszak
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Brian C. Leonard
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Andrew Blandino
- Department of Statistics, University of California Davis, Davis, CA, USA
| | - Monica J. Motta
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Glenn Yiu
- Department of Ophthalmology & Vision Science, School of Medicine, University of California Davis, Davis, CA, USA
| | - Jennifer Y. Li
- Department of Ophthalmology & Vision Science, School of Medicine, University of California Davis, Davis, CA, USA
| | - Ala Moshiri
- Department of Ophthalmology & Vision Science, School of Medicine, University of California Davis, Davis, CA, USA
| | - Sara M. Thomasy
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
- Department of Ophthalmology & Vision Science, School of Medicine, University of California Davis, Davis, CA, USA
- California National Primate Research Center, Davis, CA, USA
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Fortepiani L, Foutch BK, Wilson MR. The Effects of Sex, Oral Contraception, and Menstrual Cycle Phase on Intraocular Pressure, Central Corneal Thickness, and Foveal Thickness: A Descriptive Analysis. Vision (Basel) 2021; 5:vision5040048. [PMID: 34698316 PMCID: PMC8544721 DOI: 10.3390/vision5040048] [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: 09/09/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 01/03/2023] Open
Abstract
The primary goal of this study was to investigate the effects of sex, oral contraceptive (OC) use, and menstrual cycle phase on common ocular parameters assessed during ophthalmic evaluations, namely intraocular pressure (IOP), central corneal thickness (CCT), and foveal thickness (FT), in young healthy adults. We measured IOP, CCT, and FT in 60 participants (16 men, 16 contraceptive users, and 28 cycling women) over two sessions that characterized the menstrual cycle phase in women. For men in our study, two sessions were separated by two weeks. For women, the two sessions were scheduled during the follicular and luteal phases of the menstrual cycle. There was a trend towards higher IOP in men, and the difference was significant for white, non-Hispanic subjects and for white subjects considered separately. There was also a trend for thicker corneas in women, but men had significantly thicker foveae. CCT and FT were not different between men and OC-users, hinting at a moderating hormonal effect of oral contraceptive use. We found that IOP, CCT, and FT were equivalent between the follicular and luteal phases, which may be owing to the timing of our sessions. However, our findings strongly suggest that clinicians should consider contraceptive use during routine ophthalmic evaluations, as it could inform glaucomatous risk in women.
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Affiliation(s)
- Lourdes Fortepiani
- Rosenberg School of Optometry, University of the Incarnate Word, San Antonio, TX 78229, USA; (L.F.); (M.R.W.)
- Department of Cellular and Integrative Physiology, UT Health San Antonio, San Antonio, TX 78229, USA
| | - Brian K. Foutch
- Rosenberg School of Optometry, University of the Incarnate Word, San Antonio, TX 78229, USA; (L.F.); (M.R.W.)
- Correspondence: or ; Tel.: +1-210-930-8162
| | - Molly R. Wilson
- Rosenberg School of Optometry, University of the Incarnate Word, San Antonio, TX 78229, USA; (L.F.); (M.R.W.)
- Omni Vision, San Antonio, TX 78245, USA
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Cabeza-Gil I, Grasa J, Calvo B. A validated finite element model to reproduce Helmholtz's theory of accommodation: a powerful tool to investigate presbyopia. Ophthalmic Physiol Opt 2021; 41:1241-1253. [PMID: 34463367 DOI: 10.1111/opo.12876] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 12/20/2022]
Abstract
PURPOSE To reproduce human in vivo accommodation numerically. For that purpose, a finite element model specific for a 29-year-old subject was designed. Once the proposed numerical model was validated, the decrease in accommodative amplitude with age was simulated according to data available in the literature. METHODS In contrast with previous studies, the non-accommodated eye condition was the reference configuration. Consequently, two aspects were specifically highlighted: contraction of the ciliary muscle, which was simulated by a continuum electro-mechanical model and incorporation of initial lens capsule stresses, which allowed the lens to become accommodated after releasing the resting zonular tension. RESULTS The morphological changes and contraction of the ciliary muscle were calibrated accurately according to the experimental data from the literature. All dynamic optical and biometric lens measurements validated the model. With the proposed numerical model, presbyopia was successfully simulated. CONCLUSIONS The most widespread theory of accommodation, proposed by Helmholtz, was simulated accurately. Assuming the same initial stresses in the lens capsule over time, stiffening of the lens nucleus is the main cause of presbyopia.
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Affiliation(s)
- Iulen Cabeza-Gil
- Aragόn Institute of Engineering Research (i3A), University of Zaragoza, Zaragoza, Spain
| | - Jorge Grasa
- Aragόn Institute of Engineering Research (i3A), University of Zaragoza, Zaragoza, Spain.,Bioengineering, Biomaterials and Nanomedicine Networking Biomedical Research Centre (CIBER-BBN), Zaragoza, Spain
| | - Begoña Calvo
- Aragόn Institute of Engineering Research (i3A), University of Zaragoza, Zaragoza, Spain.,Bioengineering, Biomaterials and Nanomedicine Networking Biomedical Research Centre (CIBER-BBN), Zaragoza, Spain
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Kelekele JTK, Kayembe DL, Mwanza JC. Profile of central corneal thickness and corneal endothelial cell morpho-density of in healthy Congolese eyes. BMC Ophthalmol 2021; 21:185. [PMID: 33888064 PMCID: PMC8063471 DOI: 10.1186/s12886-021-01947-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/12/2021] [Indexed: 11/30/2022] Open
Abstract
Purpose To determine the pachymetric and corneal endothelial cell morphometric features and their relationship to ocular and systemic factors in healthy Congolese subjects. Methods Non-contact specular microscopy was used in 278 healthy eyes (278 subjects) to measure central corneal thickness (CCT), corneal endothelial cell density (CECD) along with cell size, coefficient of variation (CV) in cell size, and hexagonality (HEX). The lower and upper reference limits and average values for each parameter were determined. Correlation and association of average values with anthropo-demographic and clinical variables were assessed. Results The mean age was 38.9 ± 17.2 years (10.9–80.7 years). Average values were 504.2 ± 30.7 μm (CCT), 2907.1 ± 290.9 cells/mm2 (CECD), 348.5 ± 38.4 μm2 (cell size), 32.9 ± 3.6% (CV), and 51.8 ± 7.2% (HEX). CCT was 504.9 ± 33.6 μm in men and 503.6 ± 28.3 μm in women (p = .73); values for CECD were 2917.1 ± 253.5 cells/mm2 and 2899.2 ± 317.8 cells/mm2 (p = 0.61), respectively. Lower and upper reference limits were 449.6 μm and 566.0 μm for CCT, and 2165.3 cells/mm2 and 3414.4 cells/mm2 for CECD, respectively. CCT correlated with body mass index (BMI), (r = − 0.12, P = 0.04). CECD decreased with age (r = − 0.49, P < 0.001), BMI (r = − 0.20, P = 0.001), intraocular pressure (r = − 0.13, P = 0.029) and ocular perfusion pressure (r = − 0.28, P = 0.028). CECD decayed by 8.3 cells/mm2 or 0.30% per year of age and CCT decreased by 0.72 μm per kg/m2. Conclusions Mean central cornea was thinner, CECD higher, and references limits lower than reported in other African populations. The CCT and CECD normative values reported herein will be useful for both clinical and research purposes in this population. Supplementary Information The online version contains supplementary material available at 10.1186/s12886-021-01947-x.
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Affiliation(s)
| | - David L Kayembe
- Department of Ophthalmology, University Hospital of Kinshasa, Kinshasa, Democratic Republic of Congo
| | - Jean-Claude Mwanza
- Department of Ophthalmology, University Hospital of Kinshasa, Kinshasa, Democratic Republic of Congo.,Department of Ophthalmology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Lee SSY, Lingham G, Yazar S, Sanfilippo PG, Charng J, Chen FK, Hewitt AW, Ng F, Hammond C, Straker LM, Eastwood PR, MacGregor S, Rose KA, Lucas RM, Guggenheim JA, Saw SM, Coroneo MT, He M, Mackey DA. Rationale and protocol for the 7- and 8-year longitudinal assessments of eye health in a cohort of young adults in the Raine Study. BMJ Open 2020; 10:e033440. [PMID: 32217560 PMCID: PMC7170556 DOI: 10.1136/bmjopen-2019-033440] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
INTRODUCTION Eye diseases and visual impairment more commonly affect elderly adults, thus, the majority of ophthalmic cohort studies have focused on older adults. Cohort studies on the ocular health of younger adults, on the other hand, have been few. The Raine Study is a longitudinal study that has been following a cohort since their birth in 1989-1991. As part of the 20-year follow-up of the Raine Study, participants underwent a comprehensive eye examination. As part of the 27- and 28-year follow-ups, eye assessments are being conducted and the data collected will be compared with those of the 20-year follow-up. This will provide an estimate of population incidence and updated prevalence of ocular conditions such as myopia and keratoconus, as well as longitudinal change in ocular parameters in young Australian adults. Additionally, the data will allow exploration of the environmental, health and genetic factors underlying inter-subject differential long-term ocular changes. METHODS AND ANALYSIS Participants are being contacted via telephone, email and/or social media and invited to participate in the eye examination. At the 27-year follow-up, participants completed a follow-up eye screening, which assessed visual acuity, autorefraction, ocular biometry and ocular sun exposure. Currently, at the 28-year follow-up, a comprehensive eye examination is being conducted which, in addition to all the eye tests performed at the 27-year follow-up visit, includes tonometry, optical coherence tomography, funduscopy and anterior segment topography, among others. Outcome measures include the incidence of refractive error and pterygium, an updated prevalence of these conditions, and the 8-year change in ocular parameters. ETHICS AND DISSEMINATION The Raine Study is registered in the Australian New Zealand Clinical Trials Registry. The Gen2 20-year, 27-year and 28-year follow-ups are approved by the Human Research Ethics Committee of the University of Western Australia. Findings resulting from the study will be published in health or medical journals and presented at conferences. TRIAL REGISTRATION NUMBER ACTRN12617001599369; Active, not recruiting.
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Affiliation(s)
- Samantha Sze-Yee Lee
- Centre for Ophthalmology and Visual Science, University of Western Australia, Nedlands, Western Australia, Australia
| | - Gareth Lingham
- Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Seyhan Yazar
- Centre for Ophthalmology and Visual Science, University of Western Australia, Nedlands, Western Australia, Australia
- Single Cell and Computational Genomics Lab, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Paul G Sanfilippo
- Centre for Eye Research Australia Ltd, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
| | - Jason Charng
- Centre for Ophthalmology and Visual Science, University of Western Australia, Nedlands, Western Australia, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science, University of Western Australia, Nedlands, Western Australia, Australia
- Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Alex W Hewitt
- Centre for Eye Research Australia Ltd, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
- School of Medicine, Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia
| | - Fletcher Ng
- Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Christopher Hammond
- Department of Twin Research & Genetic Epidemiology, King's College London, London, UK
| | - Leon M Straker
- School of Physiotherapy and Exercise Science, Curtin University, Perth, Western Australia, Australia
| | - Peter R Eastwood
- Centre for Sleep Science, School of Human Sciences, University of Western Australia, Crawley, Western Australia, Australia
- Sir Charles Gairdner Hospital, West Australian Sleep Disorders Research Institute, Nedlands, Western Australia, Australia
| | - Stuart MacGregor
- Genetics and Population Health, Queensland Institute of Medical Research - QIMR, Brisbane, Queensland, Australia
| | - Kathryn A Rose
- University of Sydney, Sydney, New South Wales, Australia
| | - Robyn M Lucas
- Australian National University, Research School of Population Health, College of Health and Medicine, Canberra, Australian Capital Territory, Australia
| | - Jeremy A Guggenheim
- School of Optometry and Vision Science, Cardiff University, Cardiff, South Glamorgan, UK
| | - Seang-Mei Saw
- Singapore Eye Research Institute, Singapore
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Minas T Coroneo
- Department of Ophthalmology, University of New South Wales, Sydney, New South Wales, Australia
| | - Mingguang He
- Centre for Eye Research Australia Ltd, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
| | - David A Mackey
- Centre for Ophthalmology and Visual Science, University of Western Australia, Nedlands, Western Australia, Australia
- Centre for Eye Research Australia Ltd, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, Victoria, Australia
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Effects of aging on corneal parameters measured with Pentacam in healthy subjects. Sci Rep 2019; 9:3419. [PMID: 30833606 PMCID: PMC6399218 DOI: 10.1038/s41598-019-39234-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 01/17/2019] [Indexed: 11/08/2022] Open
Abstract
Our purpose was to prospectively analyze the age-related changes of corneal Scheimpflug parameters in healthy subjects. Thirty-five eyes of 35 volunteers (age 14-67 years) were investigated with an average interval of 3.6 years. Changes of corneal parameters (flattest keratometric reading at anterior (K1F) and posterior surface (K1B), steepest keratometric reading at anterior (K2F) and posterior surface, anterior astigmatism, posterior astigmatism (AstigB), flat axis of anterior and posterior astigmatism (AxisB), thinnest pachymetric value (PachyMin), corneal volume (CV10-mm)) were analyzed. K1F and K2F decreased significantly during observation and showed stronger decrease in younger than in older individuals. Higher values proved to be more stable. K1B decreased significantly and the degree of decrease was dependent on its baseline value and age: in young subjects low values increased, high values decreased. AstigB decreased significantly and showed a baseline-dependent significant increase from lower and a significant decrease from higher initial values. Over time, the mean AxisB shifted significantly. PachyMin and CV decreased significantly with age, especially from higher baseline values in younger subjects. The results of this longitudinal study suggest that both corneal surfaces change significantly with age. We demonstrate for the first time that age and baseline values influence age-related changes of corneal parameters.
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Ramasubramanian V, Glasser A. Distortion Correction of Visante Optical Coherence Tomography Cornea Images. Optom Vis Sci 2016; 92:1170-81. [PMID: 26540477 DOI: 10.1097/opx.0000000000000725] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Quantitative biometry measurements from uncorrected anterior segment optical coherence tomography (AS-OCT) images are inaccurate because of spatial and optical distortions. Prior reported distortion correction equations for the Visante AS-OCT were not reproducible. The goal was to calculate the distortions and provide equations to correct corneal parameters for the Visante AS-OCT to get a central corneal radius of curvature from young and older subjects. METHODS Five contact lenses (CLs) of known front and back radii of curvature and central thickness were imaged using the Visante AS-OCT (Carl Zeiss, Dublin, CA). Contact lens surface coordinates from Visante images were identified and fitted with a circle using custom Matlab image analysis software. Spatial and optical distortions of the Visante image of the CL radii of curvature and thickness were calculated and corrected. Visante images were also captured from 24 younger (aged 21 to 36 years) and 30 older (aged 36 to 48 years) human subjects. Corneal radii of curvature and thickness measurements from these subjects were corrected, and intrasession and intersession repeatabilities of the corneal parameters were calculated. RESULTS Root mean square error of radius and power of the CL surfaces after distortion correction were 0.02 mm and 0.18D for the front and 0.011 mm and 0.11D for the back, respectively. Intraclass correlation coefficient for intrasession and intersession repeatability for all the corneal parameters from the human subjects was greater than 0.88 in both age groups. CONCLUSIONS A distortion correction algorithm was developed for the Visante AS-OCT and applied to extract human corneal radius of curvature measurements.
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Saenz-Frances F, Bermúdez-Vallecilla MC, Borrego-Sanz L, Jañez L, Martinez-de-la-Casa JM, Morales-Fernandez L, Santos-Bueso E, Garcia-Sanchez J, Garcia-Feijoo J. Anatomical characterization of central, apical and minimal corneal thickness. Int J Ophthalmol 2014; 7:668-72. [PMID: 25161940 DOI: 10.3980/j.issn.2222-3959.2014.04.15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 03/12/2014] [Indexed: 11/02/2022] Open
Abstract
AIM To anatomically locate the points of minimum corneal thickness and central corneal thickness (pupil center) in relation to the corneal apex. METHODS Observational, cross-sectional study, 299 healthy volunteers. Thickness at the corneal apex (AT), minimum corneal thickness (MT) and corneal thickness at the pupil center (PT) were determined using the pentacam. Distances from the corneal apex to MT (MD) and PT (PD) were calculated and their quadrant position (taking the corneal apex as the reference) determined: point of minimum thickness (MC) and point of central thickness (PC) depending on the quadrant position. Two multivariate linear regression models were constructed to examine the influence of age, gender, power of the flattest and steepest corneal axes, position of the flattest axis, corneal volume (determined using the Pentacam) and PT on MD and PD. The effects of these variables on MC and PC were also determined in two multinomial regression models. RESULTS MT was located at a mean distance of 0.909 mm from the apex (79.4% in the inferior-temporal quadrant). PT was located at a mean distance of 0.156 mm from the apex. The linear regression model for MD indicated it was significantly influenced by corneal volume (B=-0.024; 95%CI: -0.043 to -0.004). No significant relations were identified in the linear regression model for PD or the multinomial logistic regressions for MC and PC. CONCLUSION MT was typically located at the inferior-temporal quadrant of the cornea and its distance to the corneal apex tended to decrease with the increment of corneal volume.
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Affiliation(s)
- Federico Saenz-Frances
- Department of Ophthalmology, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid 28040, Spain
| | | | - Lara Borrego-Sanz
- Department of Ophthalmology, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - Luis Jañez
- Instituto de Tecnología del Conocimiento, Universidad Complutense de Madrid, Madrid 28040, Spain
| | | | - Laura Morales-Fernandez
- Department of Ophthalmology, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - Enrique Santos-Bueso
- Department of Ophthalmology, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - Julián Garcia-Sanchez
- Department of Ophthalmology, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - Julián Garcia-Feijoo
- Department of Ophthalmology, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid 28040, Spain
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Choudhari NS, George R, Sathyamangalam RV, Raju P, Asokan R, Velumuri L, Vijaya L. Long-term change in central corneal thickness from a glaucoma perspective. Indian J Ophthalmol 2014; 61:580-4. [PMID: 24145562 PMCID: PMC3853455 DOI: 10.4103/0301-4738.119338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
AIM To investigate the longitudinal change in central corneal thickness (CCT) over 3 years in patients with glaucoma. MATERIALS AND METHODS The Chennai Glaucoma Follow-up Study, an offshoot of the Chennai Glaucoma Study, was designed to evaluate the progression of glaucoma. A cohort of participants in the Chennai Glaucoma Study that were suffering from glaucoma or were at a higher risk for glaucoma underwent comprehensive ophthalmic evaluation at the base hospital at 6-month intervals during the years 2004 to 2007. The CCT (average of 10 readings) was measured between 11 am and 1 pm on any given day using an ultrasonic pachymeter. Patients with a history of ocular surgery, corneal disease and usage of topical carbonic anhydrase inhibitor were excluded. No patient was a contact lens wearer. RESULTS One hundred and ninety-six patients (84 male, 112 female) met the inclusion criteria. We analyzed data from the right eye. The mean age of the patients was 59.97 ± 9.06 years. Fifty-nine (30.1%) of the patients were diabetic. The mean change in CCT (CCT at first patient visit--CCT at last patient visit) was 3.46 ± 7.63 μm. The mean change in CCT was 0.75 μm per year (R² = 0.00). Age, gender, intraocular pressure at the first patient visit and diabetic status had no significant influence on the magnitude of change in CCT. CONCLUSION A carefully obtained CCT reading by a trained examiner need not be repeated for at least 3 years as long as the ocular and systemic factors known to affect the measurement of CCT are constant.
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Affiliation(s)
- Nikhil S Choudhari
- Department of Glaucoma project, Chennai Glaucoma Study, Vision Research Foundation, Sankara Nethralaya, 18, College Road, Chennai 600006, India
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Abstract
PURPOSE To compare anterior and posterior corneal curvatures between eyes with primary open-angle glaucoma (POAG) and healthy eyes. METHODS This is a prospective, cross-sectional, observer-masked study. A total of 138 white subjects (one eye per patient) were consecutively recruited; 69 eyes had POAG (study group), and the other 69 comprised a group of healthy control eyes matched for age and central corneal pachymetry with the study ones. Exclusion criteria included any corneal or ocular inflammatory disease, previous ocular surgery, or treatment with carbonic anhydrase inhibitors. The same masked observer performed Goldmann applanation tonometry, ultrasound pachymetry, and Orbscan II topography in all cases. Central corneal thickness, intraocular pressure, and anterior and posterior topographic elevation maps were analyzed and compared between both groups. RESULTS Patients with POAG had greater forward shifting of the posterior corneal surface than that in healthy control eyes (p < 0.01). Significant differences in anterior corneal elevation between controls and POAG eyes were also found (p < 0.01). CONCLUSIONS Primary open-angle glaucoma eyes have a higher elevation of the posterior corneal surface than that in central corneal thickness-matched nonglaucomatous eyes.
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Hatami-Marbini H, Etebu E, Rahimi A. Swelling pressure and hydration behavior of porcine corneal stroma. Curr Eye Res 2013; 38:1124-32. [PMID: 23885800 DOI: 10.3109/02713683.2013.809769] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE The aim of this study was to characterize swelling pressure-thickness, swelling pressure-hydration and hydration-thickness relations of porcine cornea. METHODS Mechanical compression tests and free swelling experiments were performed on porcine cornea. A rheometer (DHR-2, TA Instruments) with a thermally controlled fluid chamber filled with 0.9% NaCl solution was used to measure the equilibrium swelling pressure of (n = 17) corneal stromal specimens. The samples were compressed incrementally and their swelling pressure-thickness relations were obtained. In parallel to this investigation, a transient digital imaging microscope (H800-CL, American Scope Inc.), a USB autofocus camera (UM05, ViTiny), and a precision weighing scale (AGZN100, Torbal) were simultaneously used to measure the weight-thickness relation of (n = 8) corneal specimens. This experimental study gave the thickness-hydration relationship required for expressing swelling pressure measurements as a function of hydration. RESULTS At the in vivo 666 ± 68 µm central corneal thickness, an average swelling pressure of 52 ± 13 mmHg and hydration of 3.36 ± 0.25 mg H2O/mg dry tissue were found. The swelling pressure was reported as functions of both tissue thickness and hydration. The average fixed charge density of ρF/F ~ 42.8 mM and dry density of 1.47±0.15 g/cm3 were found. The thickness-hydration relationship was only linear when the tissue thickness was within the range of physiological thickness. CONCLUSION Overall, the physiological hydration and swelling pressure of the porcine cornea were within the same range of those reported previously for other mammalian corneas such as steers, rabbits and humans. Nevertheless, the thickness-hydration behavior of the porcine cornea was only similar to that of the human cornea.
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Affiliation(s)
- Hamed Hatami-Marbini
- Computational Biomechanics Laboratory, School of Mechanical and Aerospace Engineering, Oklahoma State University , Stillwater, OK , USA
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Sakalar YB, Keklikci U, Unlu K, Alakus MF, Yildirim M, Dag U. Distribution of Central Corneal Thickness and Intraocular Pressure in a Large Population of Turkish School Children. Ophthalmic Epidemiol 2012; 19:83-8. [DOI: 10.3109/09286586.2011.649227] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Pang CE, Lee KY, Su DH, Htoon HM, Ng JY, Kumar RS, Aung T. Central corneal thickness in Chinese subjects with primary angle closure glaucoma. J Glaucoma 2012; 20:401-4. [PMID: 21654516 DOI: 10.1097/ijg.0b013e3181f3e5d9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To characterize central corneal thickness (CCT) in Chinese eyes with primary angle closure glaucoma (PACG). METHODS CCT was measured by ultrasound pachymetry in PACG eyes and compared with primary open-angle glaucoma (POAG) eyes. POAG eyes were further subdivided into high-tension glaucoma (HTG) and normal-tension glaucoma (NTG) for analysis. PACG eyes had glaucomatous optic neuropathy and visual field loss, an angle in which at least 180 degrees of angle in which the posterior trabecular meshwork was not visible, and raised intraocular pressure (IOP) and/or peripheral anterior synechiae. Both HTG (IOP >21 mm Hg) and NTG (IOP consistently <21 mm Hg) eyes had glaucomatous optic neuropathy with compatible visual field defects and open angles. Further comparison was made with CCT data of 1067 normal subjects previously enrolled in a population-based study. RESULTS We enrolled 154 patients with PACG and 300 with POAG. Mean age of PACG patients was 68.1±8.3 years compared with 71.1±12.4 years in POAG patients (P=0.002). There was no difference in mean CCT of PACG eyes (541.28±33.95 μm) and POAG eyes (539.28±34.84 μm, P=0.56) or normal eyes of control subjects (536.74±31.08 μm) (P=0.07). However, mean CCT of NTG eyes (535.23±36.10 μm) was significantly lower than that of HTG eyes (543.44±33.10 μm, P=0.04), and HTG eyes had thicker CCT than normal eyes (P=0.01). CONCLUSIONS PACG eyes had similar CCT as those with POAG or normal eyes in Chinese subjects.
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Affiliation(s)
- Claudine E Pang
- Department of Ophthalmology, Singapore Eye Research Institute and Singapore National Eye Center, Singapore
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Wang D, Singh K, Weinreb R, Kempen J, He M, Lin S. Central corneal thickness and related factors in an elderly American Chinese population. Clin Exp Ophthalmol 2011; 39:412-20. [DOI: 10.1111/j.1442-9071.2010.02472.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kohli PG, Randhawa BK, Singh KD, Randhawa GS, Kohli AK. Relation between central corneal thickness and intraocular pressure in Punjabi population. J Med Eng Technol 2009; 34:1-6. [PMID: 19995146 DOI: 10.3109/03091900903247919] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE The motive of this study was to determine the variation of central corneal thickness (CCT) in the Punjabi population and to examine its relationship with intraocular pressure (IOP) using a non-contact tonometer. The study and results emphasize the effects of age, sex and refraction on this relationship, which is important for the diagnosis and prevention of glaucoma in adequate time. METHODS The study design was a cross-sectional, population-based survey. The participants were 279 females and 253 males of Punjab Province, India, in the age group of 21-70 years. The CCT was measured using an ultrasonic pachymeter, and the IOP was measured using an air-puff tonometer in all subjects. RESULTS The mean values of CCT and IOP were observed to vary imprecisely with age. The measurement of both parameters was also affected by sex and refraction. The linear regression analysis suggests that the mean value of CCT grows progressively with increasing value of mean IOP. A significant positive correlation was identified between CCT and IOP in the age group of 21-70 years. The authors inferred that this correlation value varies prominently with age for both sexes, which needs to be investigated further. CONCLUSIONS The authors suggest that CCT is a noteworthy source of variation in IOP measurements for males as well as females belonging to different age groups, when assessing IOP as a risk for glaucoma in the Punjabi population.
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Affiliation(s)
- Poonam G Kohli
- Department of Physiology, Rajindra Government Medical College and Hospital, Patiala, Punjab, India.
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Cerviño A, Gonzalez-Meijome JM, Ferrer-Blasco T, Garcia-Resua C, Montes-Mico R, Parafita M. Determination of corneal volume from anterior topography and topographic pachymetry: application to healthy and keratoconic eyes. Ophthalmic Physiol Opt 2009; 29:652-60. [PMID: 19821928 DOI: 10.1111/j.1475-1313.2009.00642.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To describe a method to measure corneal volume from topography and pachymetry, and test its clinical use on a sample of healthy human subjects and a case of circumscribed posterior keratoconus. METHODS Corneal curvature (PCT 200 corneal topography system; Optopol Technology SA, Zawiercie, Poland) and ultrasonic topographic pachometry on 25 points (Ophthasonic A-Scan/Pachometer III; Teknar Inc., St Louis, MO, USA) were measured on each of 12 young healthy corneas and one cornea suffering from circumscribed posterior keratoconus. Topography and pachymetry data were used to calculate the coordinates for the corresponding points on the posterior surface of the cornea. TableCurve 3D software (Systat Software Inc., Chicago, IL, USA) was used to fit a surface to those points measured. Integration of the surface fitted to the data points, corresponding to the anterior and posterior corneal surfaces, was used to calculate the volume underneath each of them. Subtraction of volumes underneath anterior and posterior surfaces, taking into account an axial offset equal to the central corneal thickness, rendered corneal volume for the central 6 mm of the cornea. RESULTS Central corneal thickness ranged from 520 to 630 mum for the healthy corneas. Corneal volumes for this sample analyzed averaged 18.66 +/- 1.15 mm(3) (range 17.25-20.53 mm(3)). For the posterior keratoconic cornea, the affected area was located at about 1.5-2 mm from the corneal center on the 135 degrees hemimeridian of the right eye, observed through topographic pachymetry. Calculated corneal volume for the central 6 mm was 16.072 mm(3), noticeably lower than those found in the sample without pathology, but within the range for corneas presenting with keratoconus. CONCLUSIONS Corneal volume is a useful parameter for characterising dystrophic corneas and can aid in the detection of rare anomalies which are hardly detected with corneal topography and/or central corneal thickness evaluation. A potentially useful measure of corneal volume can be calculated from anterior corneal topography and topographic pachymetry data. Values obtained are in good agreement with previous studies using corneal tomography techniques. The methodology has been shown to have potential for retrospective analysis of data, or where no access is available to tomographical techniques.
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Affiliation(s)
- Alejandro Cerviño
- Optometry Research Group, Department of Optics, University of Valencia, Valencia, Spain
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Kamiya K, Shimizu K, Ohmoto F. Effect of aging on corneal biomechanical parameters using the ocular response analyzer. J Refract Surg 2009; 25:888-93. [PMID: 19835329 DOI: 10.3928/1081597x-20090917-10] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 11/20/2008] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess the effect of aging on corneal biomechanical parameters in a normal population. METHODS We prospectively examined 204 normal eyes of 204 healthy Japanese volunteers (68 men, 136 women; mean age 46.7+/-19.4 years [range: 19 to 89 years]). Corneal hysteresis, corneal resistance factor, corneal-compensated intraocular pressure (IOP(cc)), and Goldmann-correlated intraocular pressure (IOP(G)) were qualitatively assessed using a Reichert Ocular Response Analyzer. Central corneal thickness was measured using an ultrasound pachymeter. This measurement was performed 3 times, and the mean value obtained was used for statistical analysis. The relationships between patient age and corneal biomechanical parameters, or age and intraocular pressure (IOP), were investigated. RESULTS Mean corneal hysteresis and corneal resistance factor were 10.1+/-1.5 mmHg and 10.1+/-1.6 mmHg, respectively. Mean central corneal thickness was 539.1+/-30.9 microm. A weak, but significant, negative correlation was found between age and corneal hysteresis (Pearson's correlation coefficient r=-0.17, P=.02) and corneal resistance factor (r=-0.18 P=.01). On the other hand, no significant correlation was found between age and central corneal thickness (r=-0.06, P=.41), age and IOP(cc) (r=-0.02, P=.82), or age and IOP(G) (r=-0.11, P=.11). CONCLUSIONS Corneal biomechanical parameters are significantly decreased by aging without significant changes in central corneal thickness or IOP, suggesting that age-related structural changes resulting from collagen cross-linking may lead to a reduction of corneal biomechanical variables independent of central corneal thickness or IOP.
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Affiliation(s)
- Kazutaka Kamiya
- Department of Ophthalmology, University of Kitasato School of Medicine, Kanagawa, Japan.
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Lee DG, Choi SH. Measurement of Anterior Segment Using Visante OCT in Koreans. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2009. [DOI: 10.3341/jkos.2009.50.4.542] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Deok Goo Lee
- Department of Ophthalmology, College of Medicine, Chungnam National University, Daejeon, Korea
| | - Si Hwan Choi
- Department of Ophthalmology, College of Medicine, Chungnam National University, Daejeon, Korea
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Song HT, Kim YJ, Lee SJ, Moon YS. Relations between age, weight, refractive error and eye shape by computerized tomography in children. KOREAN JOURNAL OF OPHTHALMOLOGY 2007; 21:163-8. [PMID: 17804923 PMCID: PMC2629680 DOI: 10.3341/kjo.2007.21.3.163] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose To investigate relationships between age, weight, refractive error, and morphologic changes in children's eyes by computerized tomography (CT). Methods Of the 772 eyes of 386 patients under the age of 20 years, who visited our Department of Ophthalmology between January 2005 to August 2006 and underwent CT of the orbit, 406 eyes of 354 patients with clear CT images and normal eyeball contour were enrolled in the present retrospective study. The axial lengths, widths, horizontal and vertical lengths, refractive errors, and body weight of eyes were measured, and relationship between these parameters were investigated. Results Axial length was found to correlate significantly with eye width (r=0.914), and in emmetropic eyes and myopic eyes, axial lengths and widths were found to increase as age and body weight increased. Axial lengths increased rapidly until age 10, and then increased slowly. In emmetropic eyes, widths / axial lengths increased with age, but in myopic eyes these decreased as age or severity of myopia increased. Moreover, as age increased, the myopic population and severity also increased. Conclusions The axial length was longer in case of myopia compared to emmetropia in all age groups and there was almost no difference in the increase rate of axial length by the age of myopia and emmetropia. However, the width was wider in case of myopia compared to emmetropia in all age groups and the increase rate of width in myopia by age was smaller than that of emmetropia. Myopia showed decreasing rate of width/axial length with increase of age, from 1.004 in 5 years to 0.971 in 20 years. However, emmetropia showed increasing rate of width/axial length with increase of age, from 0.990 in 5 years to 1.006 in 20 years.
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Affiliation(s)
- Ha Tae Song
- Department of Ophthalmology, Inha University College of Medicine, Inha University Hospital, Incheon, Korea
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Durkin SR, Tan EWH, Casson RJ, Selva D, Newland HS. Central corneal thickness among Aboriginal people attending eye clinics in remote South Australia. Clin Exp Ophthalmol 2007; 35:728-32. [DOI: 10.1111/j.1442-9071.2007.01574.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Jonuscheit S, Doughty MJ, Button NF. On the use of Orbscan II to assess the peripheral corneal thickness in humans: a comparison with ultrasound pachometry measures. Ophthalmic Physiol Opt 2007; 27:179-89. [PMID: 17324208 DOI: 10.1111/j.1475-1313.2006.00459.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To compare the measures of corneal thickness measurements obtained by an optical scanning slit method with those obtained by an ultrasound (US) pachometer, with special interest in the mid-peripheral (2.5 mm from centre) and peripheral (4.5 mm from centre) region of the cornea. METHODS Three measures of corneal thickness were taken using Orbscan II and then by US pachometry (under topical anaesthesia with benoxinate 0.4%) on 24 adults, aged 20-58 years and with up to 8.5 D of myopia. The full Orbscan topography maps were used to extract single point data along the horizontal corneal meridian for the geometric centre, 2.5 mm from centre (nasal and temporal) and 4.5 mm (nasal and temporal) from centre. No correction factor was used for the Orbscan data. The same set of measures were made with the US pachometer. In all cases, the averages of three (centre) or six (mid-periphery and periphery) readings were taken as the measurements from each cornea. RESULTS Orbscan readings on the right eyes averaged 0.576, 0.632 and 0.712 mm for central, mid-peripheral and peripheral sites with average values for emmetropic subjects (<1 DS, n = 12) being marginally higher than for myopic subjects (average - 4.00 DS, n = 12). For US pachometry, the average values were however 0.522, 0.554 and 0.606 mm. Similar results were obtained on left eyes. Combining data from both eyes also showed that the mean difference between Orbscan II and US measures was not constant across the cornea, being 0.055 +/- 0.014 mm at the centre, 0.080 +/- 0.019 mm at mid-peripheral locations and 0.107 +/- 0.046 mm at the peripheral sites. These differences persisted after application of the generally recommended acoustic factor (x0.92) to all of the Orbscan readings. CONCLUSIONS A single acoustic factor correction cannot be applied to all corneal thickness measures made with an Orbscan II to equate the measures to those made with an US pachometer.
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Affiliation(s)
- Sven Jonuscheit
- Department of Vision Sciences, Glasgow Caledonian University, Glasgow G4 OBA, UK
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Weizer JS, Stinnett SS, Herndon LW. Longitudinal changes in central corneal thickness and their relation to glaucoma status: an 8 year follow up study. Br J Ophthalmol 2006; 90:732-6. [PMID: 16481376 PMCID: PMC1860195 DOI: 10.1136/bjo.2005.087155] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIMS To determine if central corneal thickness (CCT) changes over time and if this change relates to glaucoma progression. METHODS 39 patients (64 eyes) with open angle glaucoma, ocular hypertension, glaucoma suspect status, or a normal eye examination were examined at two visits. CCT, age, race, sex, family history of glaucoma, presence of diabetes and systemic hypertension, diagnosis, visual acuity, spherical equivalent, intraocular pressure, vertical and horizontal cup to disc ratios, number of glaucoma medications prescribed, Advanced Glaucoma Intervention Study (AGIS) score and mean deviation of Humphrey visual fields, and interventions required were recorded. Statistical analysis used the Wilcoxon signed ranks test, linear regression, and analysis of variance. RESULTS Between the two visits (mean 8.2 years apart), mean CCT decreased by 17 mum in right eyes (p<0.002) and by 23 mum in left eyes (p<0.001). This decrease was greater in right eyes of patients with primary open angle glaucoma than in normals (p = 0.041). There was no significant association between change in CCT and other examination parameters. Change in CCT was not associated with topical carbonic anhydrase inhibitor use. CONCLUSION In this longitudinal study, CCT decreased over time, but this may not be related to glaucoma progression.
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Affiliation(s)
- J S Weizer
- Duke University Eye Center, DUMC, Durham, NC 27710, USA
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Suzuki S, Suzuki Y, Iwase A, Araie M. Corneal Thickness in an Ophthalmologically Normal Japanese Population. Ophthalmology 2005; 112:1327-36. [PMID: 15964631 DOI: 10.1016/j.ophtha.2005.03.022] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2004] [Accepted: 03/06/2005] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To investigate the distribution of central corneal thickness (CCT) and factors correlating with CCT in a large-scale population of ophthalmologically normal Japanese persons. DESIGN Cross-sectional study. PARTICIPANTS Participants (n = 7313; 2848 men and 4465 women) were selected as an ophthalmologically normal Japanese sample using the following exclusion criteria: abnormal results suggestive of any eye diseases revealed on slit-lamp examination, fundus photography, or visual field test using frequency doubling technology; corrected visual acuity worse than 0.7; and contact lens wear within 1 week. All study participants were identified from The Eye Disease Screening Service in Tajimi city during the period from September, 2000, through October, 2001. METHODS The CCT was measured by SP-2000P specular microscopy (Topcon, Tokyo, Japan). Age, gender, body mass index, systolic blood pressure, laterality, refraction, corneal radius, and intraocular pressure (IOP) data were collected from the records. MAIN OUTCOME MEASURES The CCT value and its correlating factors. RESULTS Average CCT in this ophthalmologically normal Japanese population was 517.5+/-29.8 microm (mean+/-standard deviation; n = 7313) and was greater in men (521.5+/-30.3 microm) than in women (514.4+/-29.0 microm). The CCT positively correlated with IOP and corneal radius and negatively correlated with refraction, although the correlation was weak. Intraocular pressure measured with a Goldmann applanation tonometer positively correlated with CCT, and the correction was not affected by age (corrected IOP = IOP reading -0.012 [CCT (microm) - 520]). CONCLUSIONS Using optical pachymetry, CCT in normal Japanese persons was defined as 517.5+/-29.8 microm. Men had greater CCT measurements than women. The CCT measurements positively correlated with IOP and corneal radius and negatively correlated with age and refraction in men. Intraocular pressure positively correlated with CCT, regardless of age.
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Affiliation(s)
- Shigenobu Suzuki
- Division of Ophthalmology, National Cancer Center Hospital, Tokyo, Japan
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Aghaian E, Choe JE, Lin S, Stamper RL. Central corneal thickness of Caucasians, Chinese, Hispanics, Filipinos, African Americans, and Japanese in a glaucoma clinic. Ophthalmology 2004; 111:2211-9. [PMID: 15582076 DOI: 10.1016/j.ophtha.2004.06.013] [Citation(s) in RCA: 215] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2004] [Accepted: 06/02/2004] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To characterize the central corneal thickness (CCT) of Asian (Chinese, Japanese, and Filipino), Caucasian, Hispanic, and African American patients in a multiethnic glaucoma practice. DESIGN Retrospective study (chart review). PARTICIPANTS Glaucomatous (n = 600) and nonglaucomatous (n = 201) eyes of 801 patients examined in a San Francisco glaucoma clinic from June 2002 to April 2004 who met inclusion criteria were included in the study. The 6 racial (ethnic) groups represented in the study were Caucasian (n = 186, 23.2%), Chinese (n = 157, 19.6%), Japanese (n = 121, 15.1%), Hispanic (n = 116, 14.5%), Filipino (n = 114, 14.2%), and African American (n = 107, 13.4%). METHODS Central corneal thickness was measured by means of ultrasound pachymetry in Asian (Chinese, Japanese, and Filipino), Caucasian, Hispanic, and African American participants with glaucomatous and normal eyes. The relationship between CCT and race was investigated using multivariate regression analyses, controlling for confounders. One eye of each of 801 participants was included for analysis. MAIN OUTCOME MEASURES Correlation of mean CCT with race, glaucoma diagnosis, age, spherical equivalent, gender, and history of ocular surgery. RESULTS The mean CCT of all participants was 542.9 mum. Central corneal thicknesses of Chinese (555.6 microm), Caucasian (550.4 microm), Filipino (550.6 microm), and Hispanic (548.1 microm) participants did not significantly differ. The CCT of Japanese participants (531.7 microm) was significantly less than that of Caucasians, Chinese, Filipinos, and Hispanics (all, P< or =0.001) and greater than that of African Americans (P = 0.03). African Americans had a CCT (521.0.0 microm) less than that of all races (P< or =0.05). Glaucoma suspects and patients with normal tension glaucoma (NTG), primary open-angle glaucoma (POAG), pseudoexfoliation glaucoma (PEX), and chronic angle-closure glaucoma (CACG) had corneas significantly thinner than those of normal participants (P< or =0.004), whereas ocular hypertensives had significantly thicker corneas (P<0.0001). Among all participants, decreasing values of CCT were significantly related to older age (P<0.01). Less negative or more positive refractive errors, gender, and history of ocular surgery were not associated with changes in CCT (P = 0.38, P = 0.50, and P = 0.97, respectively). CONCLUSIONS Studies examining individual Asian subpopulations in isolation suggest that differences in CCT may exist among different Asian groups. The results of this study indicate that CCT does, in fact, vary among Asian subpopulations; Japanese have thinner corneas than Chinese and Filipinos. Caucasians, Chinese, Hispanics, and Filipinos have comparable CCT measurements, whereas the corneas of African Americans are significantly thinner. Additionally, older individuals; glaucoma suspects; and participants with NTG, POAG, PEX, and CACG have thinner corneas. Ocular hypertensives, however, have thicker corneas.
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Affiliation(s)
- Elsa Aghaian
- Department of Ophthalmology, University of California, San Francisco, California, USA
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Evereklioglu C, Madenci E, Bayazit YA, Yilmaz K, Balat A, Bekir NA. Central corneal thickness is lower in osteogenesis imperfecta and negatively correlates with the presence of blue sclera. Ophthalmic Physiol Opt 2002; 22:511-5. [PMID: 12477015 DOI: 10.1046/j.1475-1313.2002.00062.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Osteogenesis imperfecta (OI) is a rare, autosomal-inherited, connective tissue disorder characterised by bone fractures, deafness and blue sclera. Additional ocular findings are decreased ocular rigidity, myopia, glaucoma, keratoconus, corneal opacity, small corneal diameter and congenital Bowman's layer agenesis. PURPOSE This cross-sectional, masked, case-control study aimed to assess whether central corneal thickness (CCT) is affected in patients with OI and to focus on the clinical significance of scleral blueness. MATERIALS AND METHODS Twenty-three children with OI (13 boys, 10 girls) and 15 age-, sex- and refraction-matched healthy control subjects (eight boys, seven girls) were assessed for CCT by ultrasound pachymetry. The CCT was compared between two different patient subgroups (type-I OI with blue sclera, n = 12; type-IV OI without blue sclera, n = 11). Mann-Whitney U-test or analysis of variance was used as indicated and only right eyes of each subject were included in statistical analysis. Results were expressed as mean +/- S.D. and statistical significance was taken as p < 0.05. RESULTS Mean age and sex distribution was similar between the groups (10.1+/-2.5 vs 9.8+/-1.8 years, p > 0.05). Patients with OI had significantly lower CCT (459.5+/-24.6 microm) than in control subjects (543.6+/-21.4 microm; p < 0.001). The CCT was below 500 microm in 22 of 23 children (95.6%) with OI, 15 of which (65.2%) were below 450 microm. In contrast, CCT was over 500 microm in all eyes in the control group. Type-I OI eyes with blue sclera had significantly (p = 0.005) lower CCT readings (446.5+/-16.3 microm) than type-IV OI eyes without blue sclera (473.6+/-25.0 microm). Mean keratometric values were similar between the groups (44.2+/-1.7 vs 43.8+/-1.6 dioptre, p > 0.05). Mean cycloplegic refraction was similar between the groups (-0.32+/-0.5 vs -0.18+/-0.4 dioptre; p > 0.05), although five of 23 OI patients had myopia, and mean intraocular pressure was lower in OI patients than controls (12.7+/-1.8 mmHg vs 15.6+/-1.9 mmHg; p < 0.001). CONCLUSIONS The CCT is thinner and negatively correlated with the blueness of the sclera in patients with OI. The CCT readings may therefore be of utmost importance in the diagnosis of OI. An ophthalmologist should be aware of an artificially low intraocular pressure measurement in such patients. In addition, when considering a keratorefractive treatment, CCT must be evaluated carefully to avoid unexpected results or complications. Sturdy protective spectacles should be prescribed to those who are not bed bound. Possible correlation of low CCT with biochemical changes in scleral collagen or systemic parameters awaits further investigation.
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Affiliation(s)
- Cem Evereklioglu
- Department of Ophthalmology, Gaziantep University Medical Faculty, Research Hospital, Turkey.
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Evereklioglu C, Yilmaz K, Bekir NA. Decreased central corneal thickness in children with Down syndrome. J Pediatr Ophthalmol Strabismus 2002; 39:274-7. [PMID: 12353899 DOI: 10.3928/0191-3913-20020901-07] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE A cross-sectional, masked, case-control study was undertaken to investigate whether central corneal thickness is affected in children with Down syndrome and to focus on its clinical significance. PARTICIPANTS AND METHODS Twenty-eight children with Down syndrome (15 boys and 13 girls) aged 5 to 15 years and 20 age-matched and gender-matched healthy control subjects (11 boys and 9 girls) from a similar ethnic background were enrolled in the study. Central corneal thickness was measured by ultrasound pachymetry. Only the right eye of each child in each group was included in the statistical analysis. The Mann-Whitney U test was used and a P value of less than .05 was considered significant. RESULTS The mean ages of the children with Down syndrome (9.28 +/- 3.47 years) and the healthy control subjects (8.75 +/- 3.30 years) were comparable (P > .05). Central corneal thickness values were below 500 microm in 19 (67.8%) of the 28 children with Down syndrome, 4 of which were less than 450 microm. However, all central corneal thickness measurements in the control eyes were more than 500 microm. The mean central corneal thickness in the children with Down syndrome was significantly (P < .001) less (488.39 +/- 39.87 microm) than that in the healthy control subjects (536.25 +/- 20.70 microm). Mean keratometric values were significantly (P < .001) higher in the eyes of the children with Down syndrome (46.35 +/- 1.28 D) than in the eyes of the control subjects (43.32 +/- 1.15 D). CONCLUSIONS Children with Down syndrome had a decreased central corneal thickness compared with healthy control subjects. Decreased central corneal thickness may give an artificially low intraocular pressure measurement by applanation tonometry. Central corneal thickness must be considered when developing approaches for keratorefractive treatment of patients with Down syndrome.
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Affiliation(s)
- Cem Evereklioglu
- Gaziantep University, Medical Faculty, Research Hospital, Turkey
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Eysteinsson T, Jonasson F, Sasaki H, Arnarsson A, Sverrisson T, Sasaki K, Stefánsson E. Central corneal thickness, radius of the corneal curvature and intraocular pressure in normal subjects using non-contact techniques: Reykjavik Eye Study. ACTA OPHTHALMOLOGICA SCANDINAVICA 2002; 80:11-5. [PMID: 11906297 DOI: 10.1034/j.1600-0420.2002.800103.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
PURPOSE To establish a population profile of central corneal thickness (CCT), radius of the corneal curvature (CC) and intraocular pressure (IOP) and the relationships between them using non-contact techniques. METHODS We used a population-based random sample of 415 male and 510 female Caucasians aged 50 years and older. CCT and the radius of CC were measured with Scheimpflug anterior segment photography. IOP was measured with air-puff tonometry. RESULTS The mean IOP of right eyes was 15.1 mmHg (SD 3.3) among men and 15.8 mmHg among women (SD 3.1), which is a statistically significant difference. The mean radius of CC for male right eyes was 7.78 (SD 0.60) and for females 7.62 (SD 0.58) which is also statistically significant. Mean CCT for male right eyes was 0.528 mm (SD 0.041) and for females 0.526 mm (SD 0.037), which is not a significant difference. Linear regression analysis shows no relationship between the radius of CC and IOP or between age and radius of CC. Linear regression analysis of the relationship between CCT and IOP suggests higher IOP measurements with thicker corneas. There was no significant correlation between age and CCT. CONCLUSION IOP was found to be independent of age and significantly higher in females than in males. Radius of CC was found to be age-independent and significantly steeper in females than in males. CCT appears to be independent of age and gender. Greater CCT is associated with higher mean IOP.
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Affiliation(s)
- Thor Eysteinsson
- Department of Ophthalmology, National University Hospital, University of Iceland, Iceland
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Nomura H, Ando F, Niino N, Shimokata H, Miyake Y. The relationship between age and intraocular pressure in a Japanese population: the influence of central corneal thickness. Curr Eye Res 2002; 24:81-5. [PMID: 12187477 DOI: 10.1076/ceyr.24.2.81.8161] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
PURPOSE Previous cross-sectional Japanese studies have shown that intraocular pressure (IOP) decreases with age. However, central corneal thickness (CCT) variation should also be considered when examining the relationship between age and IOP, since tonometry has an inherent measurement error due to CCT variations. This study investigates the influence of CCT variation on the age-IOP relationship in a Japanese population. METHODS The right eyes of 1317 subjects from 40 to 80 years old selected from a general population using a random sampling method were assessed in cross-section. The IOP was measured with a non-contact tonometer, and CCT was measured with a specular microscope. The relationships between age, IOP, and CCT were assessed using correlation analyses, while the relationship between age and IOP controlled for CCT, blood pressure, and body mass index was investigated using multivariate regression analyses. RESULTS The mean (+/- SD) IOP value was 13.6 (+/- 2.6) mmHg in men and 13.3 (+/- 2.6) mmHg in women. The IOP correlated inversely with age in men (r = -0.14, p < 0.001), but showed only a marginal inverse correlation in women (r = -0.07, p = 0.066). The mean (+/- SD) CCT value was 518.3 (+/- 33.2) microm in men and 511.1 (+/- 33.0) microm in women. Only in men was an inverse correlation seen between CCT and age (r = -0.10, p = 0.009), but both genders had positive correlations between CCT and IOP (man: r = 0.44, p < 0.001; woman: r = 0.48, p < 0.001). In multivariate analyses, CCT was shown to have an effect on IOP measurement, however, it was shown that IOP still decreases with age in both sexes even when adjusted for CCT (p = 0.001). CONCLUSIONS The IOP decreases with age in the Japanese, and CCT variation has practically no effect on the unique age-IOP relationship.
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Affiliation(s)
- Hideki Nomura
- Department of Ophthalmology, Chubu National Hospital, Obu, Aichi, Japan.
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Abstract
PURPOSE To measure central corneal thickness (CCT) in patients with Behçet's disease (BD), particularly in the active disease. MATERIALS AND METHODS We measured CCT by ultrasound pachymetry in 64 patients with Behçet's disease and in 20 healthy controls. Forty-one of the patients with BD had ocular involvement and 23 none; 19 of the 41 with ocular involvement were in an active period and 22 had inactive disease. RESULTS The mean CCT in the group with active ocular involvement was significantly higher (589+/-27 microm) than in the control group (553+/-21 microm) (p = 0.003), the group with inactive ocular involvement (560+/-26 microm) (p < 0.001), and the group with no ocular involvement (558+/-25 microm) (p < 0.001). After appropriate treatment of patients with active ocular involvement, the mean CCT returned nearly to normal (563+/-20 microm) and the difference from controls was not significant. There was no significant difference for the mean CCT between controls and the patients with no ocular involvement or with inactive ocular involvement. CONCLUSIONS Behçet's patients with active ocular involvement have a thicker CCT than patients with inactive ocular involvement. There was no difference in CCT between controls and patients with no ocular involvement. The CCT of patients with active ocular involvement returned to nearly normal after treatment. CCT must be taken into account when developing a managing and following approach for Behcet's patients with active ocular involvement.
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Affiliation(s)
- C Evereklioglu
- Inönü University Medical Faculty, Turgut Ozal Medical Center, Research Hospital, Malatya, Turkey.
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Ventura AC, Wälti R, Böhnke M. Corneal thickness and endothelial density before and after cataract surgery. Br J Ophthalmol 2001; 85:18-20. [PMID: 11133705 PMCID: PMC1723680 DOI: 10.1136/bjo.85.1.18] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIMS Deturgescence of the corneal stroma is controlled by the pumping action of the endothelial layer and can be monitored by measurement of central corneal thickness (pachymetry). Loss or damage of endothelial cells leads to an increase in corneal thickness, which may ultimately induce corneal decompensation and loss of vision. Little is known about the effect of moderate reductions in endothelial cell number on the thickness of the corneal stroma. This study aimed to investigate this matter further using patients who had incurred moderate decreases in their endothelial cell counts as a result of cataract surgery. METHODS Central corneal thickness was measured 1 day before surgery, 1 day after surgery, and again at 3 months or 1 year. Endothelial cell counts were also performed 1 day before surgery and thereafter at 3 months or 1 year after surgery. The relationship between these two parameters was assessed statistically. Precise measurements of central corneal thickness were made by optical low coherence reflectometry. For comparative purposes, this parameter was also determined by ultrasonic pachymetry. Central corneal endothelial cell numerical density was estimated on photomicrographs taken with a specular microscope. RESULTS All patients had significant postoperative corneal swelling on the day after surgery; preoperative values were restored by 3 and 12 months, even though significant endothelial cell losses had occurred. No correlation existed between central corneal thickness and central corneal endothelial cell numerical density. Measurements estimated by ultrasonic pachymetry were more variable and significantly higher than those determined by optical low coherence reflectometry. CONCLUSION As long as the numerical density of the corneal endothelial cells does not fall below the physiological threshold, a moderate decrease in this parameter does not compromise the pumping activity of the layer as a whole.
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Affiliation(s)
- A C Ventura
- Augenklinik des Inselspitals, Universität Bern, CH-3010 Bern, Switzerland
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Abstract
PURPOSE To compare the repeatability of three measures of corneal thickness: Orbscan Slitscan pachymetry, ultrasound pachymetry, and optical pachymetry. METHODS Twenty normal subjects were tested on three occasions. Two occurred on the same day and the third was on a different day at approximately the same time of day as one of the first two visits. Central corneal thickness of the right eye was measured with a Haag-Streit optical pachymeter, a Humphrey Model 855 ultrasound pachymeter, and the Orbscan system. Day-to-day and same-day repeatability was assessed by calculating the difference between the values from two visits and determining the mean difference, the SD, and the 95% limits of agreement (LoA) (LoA = mean +/- 1.96 SD). RESULTS Mean (+/- SD) central corneal thickness as measured by each instrument was as follows: 539 +/- 33 microm for optical pachymetry, 542 +/- 33 microm for ultrasound pachymetry, and 596 +/- 40 microm for Orbscan pachymetry. For day-to-day comparisons, optical pachymetry showed the poorest repeatability with 95% LoA of -61 to +32 microm. Ultrasound pachymetry showed better repeatability with 95% LoA of -22 to +24 microm. The Orbscan showed the best repeatability centrally with 95% LoA of -10 to +17 microm. Peripheral Orbscan pachymetry was less repeatable than that measured centrally but still more repeatable than central optical pachymetry. Similar results were found with same-day comparisons. CONCLUSION The Orbscan system is the most repeatable technique for measuring corneal thickness but shows a significant bias toward greater corneal thickness measures than both ultrasound and optical pachymetry.
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Affiliation(s)
- M W Marsich
- The Ohio State University, College of Optometry, Columbus 43210, USA
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Doughty MJ, Zaman ML. Human corneal thickness and its impact on intraocular pressure measures: a review and meta-analysis approach. Surv Ophthalmol 2000; 44:367-408. [PMID: 10734239 DOI: 10.1016/s0039-6257(00)00110-7] [Citation(s) in RCA: 939] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We determined the "normal" central corneal thickness (CCT) value in human corneas based on reported literature values for within-study average CCT values, and used this as a reference to assess the reported impact of physiological variables (especially age and diurnal effects), contact lens wear, pharmaceuticals, ocular disease, and ophthalmic surgery on CCT. With the expected CCT and its variance defined, it should be possible to determine the potential impact of differences in CCT in intraocular pressure (IOP) assessments, especially by applanation tonometry, using a meta-analysis approach. Some 600 sets of CCT data were identified from the worldwide literature over the period of 1968 through mid-1999, of which 134 included IOP measures as well. The within-study average CCT values and reported variance (SD) was noted along with the number of eyes and any special characteristics, including probable ethnic origin of the study subjects. Various sets of data were subjected to statistical analyses. From 300 data sets from eyes designated as normal, the group-averaged CCT was 0.534 mm. From 230 data sets where interindividual variance was reported, the group-averaged CCT was 0.536 mm (median 0.536 mm; average SD of 0. 031 mm, average coefficient of variation = 5.8%). Overall, studies using slit-lamp-based pachometry have reported marginally lower CCT values (average 0.530 mm, average SD 0.029 mm) compared to ultrasound-based studies (average 0.544, average SD 0.034 mm), which perhaps reflects the type of individual studied (non-surgical vs. pre-surgical patients) rather than the technique itself. A slight chronological increase in reported average CCT values (approximately 0.006 mm/decade) was evident, but a substantial chronological increase was evident for ultrasound pachometry studies (approximately 0.015 mm/decade). Within the meta-analysis-generated average and variance, age had no obvious impact on CCT measures for *whites, although an age-related decline in CCT is evident for non-whites. Any diurnal effects are likely concealed within the expected variance in CCT. Contact lens wear and pharmaceuticals generally produced changes in CCT that were well within the expected variance in CCT. Of the ocular diseases, only those associated with collagen disorders (including keratoconus) or endothelial-based corneal dystrophies (e.g., Fuchs) were likely to result in decreases or increases, respectively, of CCT beyond the normal variance. Routine contact lens wear and diseases such as diabetes seem unlikely to produce changes in CCT of a magnitude that would justify pachometry as a monitoring method beyond routine slit-lamp evaluation. Increases in CCT beyond the expected variance were reported after a range of intraocular surgeries (cataract operations, penetrating keratoplasty), whereas photorefractive surgery produces a measurable decrease in CCT. A meta-analysis of possible association between CCT and IOP measures of 133 data sets, regardless of the type of eyes assessed, revealed a statistically significant correlation; a 10% difference in CCT would result in a 3. 4 +/- 0.9 mm Hg difference in IOP (P </= 0.001, r = 0.419). The observed phenomenon was much smaller for eyes designated as healthy (1.1 +/- 0.6 mm Hg for a 10% difference in CCT, P = 0.023, r = 0. 331). For eyes with chronic diseases, the change was 2.5 +/- 1.1 mm Hg for a 10% difference in CCT (P = 0.005, r = 0.450), whereas a substantial but highly variable association was seen for eyes with acute onset disease (approximately 10.0 +/- 3.1 mm Hg for a 10% difference in CCT, P = 0.004, r = 0.623). Based on the meta-analysis, normal CCT in white adults would be expected to be within +/-11.6% (+/-2 SD) of 0.535 mm, i.e., 0.473-0.597 mm (95% CI, 0.474-0.596). The impact of CCT on applanation tonometry of healthy eyes is unlikely to achieve clinical significance, but for corneas of eyes with chronic disease, pachometry should be performed if the tonometry reveals IOP readi
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Affiliation(s)
- M J Doughty
- Department of Vision Sciences, Glasgow-Caledonian University, Glasgow, United Kingdom
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Parafita M, González-Meijome J, Dı́az-Rey J, González-Pérez J, Yebra-Pimentel E. Corneal thickness mapping by topographical ultrasonic pachometry. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s0892-8967(01)00051-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Parafita M, Yebra-Pimentel E, Giraldez MJ, González-Pérez J, érez-Martín MV, González-Meijome J. Further information on the knowledge of topographical corneal thickness. INTERNATIONAL CONTACT LENS CLINIC (NEW YORK, N.Y.) 1999; 26:128-137. [PMID: 11166139 DOI: 10.1016/s0892-8967(00)00037-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Central and peripheral corneal thickness has been used increasingly to obtain information about physiologic and clinical conditions of the cornea. In this study, a new method based on ultrasonic pachometry for topographical corneal thickness measurement is described. Results suggest that the technique is reliable for clinical determination of global corneal thickness. Measurements taken by one observer on different sessions (intersession variation) and measurements taken by different observers (interobserver variation) are not significant different (p = 0.586 and 0.273, respectively). This new ultrasound topographical pachometric method can be considered a useful tool for determination of topographical corneal thickness. It has implications for the use of topographical ultrasonic pachometry in contact lenses research, refractive surgery, and management of different pathologic conditions.
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Affiliation(s)
- M Parafita
- Departments of Ophthalmology and Applied Physics School of Optics and Optometry University of Santiago de Compostela, Galicia, Spain
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Siu AW. Photo-pachometer: an instrument for the objective non-contact corneal thickness measurement. Med Eng Phys 1998; 20:109-13. [PMID: 9679229 DOI: 10.1016/s1350-4533(98)00005-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new instrument to measure corneal thickness is described. The design was based on the well-established optical principle of pachometry and its operation required only basic clinical skills. The instrument measures corneal thickness using a newly developed computer-aided paradigm in order to minimise the inter- and intra-subject variability commonly associated with the original optical technique. Preliminary clinical trials showed that it provides fast, repeatable and objective measurements comparable to ultrasonic pachometry, and no physical contact with the eye was required throughout the procedure. It combines the advantages of the two currently employed techniques and it has potential clinical applications in monitoring the dynamic corneal hydration response in vivo.
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Affiliation(s)
- A W Siu
- Department of Optometry and Radiography, Faculty of Health and Social Sciences, Hong Kong Polytechnic University, Hung Hom
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Lam AKC, Douthwaite WA. The effect of an artificially-elevated intraocular pressure on corneal thickness in Chinese eye. Ophthalmic Physiol Opt 1997. [DOI: 10.1111/j.1475-1313.1997.tb00074.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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39
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Lam AKC, Douthwaite WA. Measurement of posterior corneal asphericity on Hong Kong Chinese: A pilot study. Ophthalmic Physiol Opt 1997. [DOI: 10.1111/j.1475-1313.1997.tb00066.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wolfs RC, Klaver CC, Vingerling JR, Grobbee DE, Hofman A, de Jong PT. Distribution of central corneal thickness and its association with intraocular pressure: The Rotterdam Study. Am J Ophthalmol 1997; 123:767-72. [PMID: 9535620 DOI: 10.1016/s0002-9394(14)71125-0] [Citation(s) in RCA: 288] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE To perform a cross-sectional study on the distribution of central corneal thickness and its association with intraocular pressure in an elderly population. METHODS We measured central corneal thickness and intraocular pressure in 395 subjects (352 control subjects, 13 patients with ocular hypertension, and 30 patients with primary open-angle glaucoma) aged 55 years or more. RESULTS Mean central corneal thickness in the 352 control subjects was 537.4 microm (95% confidence interval [CI], 533.8 to 540.9 microm; range, 427 to 620 microm), with a maximal difference between eyes of 42 microm. There were no differences between sexes and no significant association with age. Linear regression analysis showed an increase of 0.19 mm Hg in intraocular pressure with each 10-microm increase in central corneal thickness (95% CI, 0.09 to 0.28 mm Hg). This association was similar in both eyes and in both sexes. The 13 patients with ocular hypertension had corneas a mean of 16.0 microm thicker (95% CI, -2.6 to +34.6 microm) compared with control subjects (P = .093); the 30 patients with primary open-angle glaucoma had corneas a mean of 21.5 microm thinner (95% CI, 8.8 to 34.1 microm) compared with control subjects (P = .001). CONCLUSION Mean central corneal thickness was similar to that found in clinical studies, was slightly higher in patients with ocular hypertension, and was significantly lower in patients with primary open-angle glaucoma. Intraocular pressure was positively related with central corneal thickness. Central corneal thickness may influence the division between normal and increased intraocular pressure at a simple cutoff point of 21 mm Hg.
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Affiliation(s)
- R C Wolfs
- Department of Ophthalmology, Erasmus University Medical School, Rotterdam, The Netherlands
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