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Llorens-Quintana C, Li Y, Chen S, Fujimoto JG, Huang D. Characterization of the external limbus on corneoscleral topography with ultrawide-field optical coherence tomography. Cont Lens Anterior Eye 2023; 46:102065. [PMID: 37827941 PMCID: PMC10842492 DOI: 10.1016/j.clae.2023.102065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 09/04/2023] [Accepted: 09/28/2023] [Indexed: 10/14/2023]
Abstract
PURPOSE To present a new method for 3-dimensional external limbal demarcation on corneoscleral topography derived from optical coherence tomography (OCT). Limbal shape is investigated and compared to other landmarks. METHODS Images from the anterior segment were obtained with a ultrawide-field (20 mm) OCT. An automated algorithm was developed to demarcate the topographic limbus based on the transition from corneal to scleral curvature. The internal limbus was manually identified as the scleral spur on the OCT images. The external topographic limbus was fit with a circle on a plane. Ellipticity and ovality were defined by the lateral limbal deviation from the best-fit circle. Toricity was defined by the axial deviation from the best-fit plane. Repeatability was assessed by the within-subject standard deviation from two repeated measurements. For comparison, the white-to-white (WTW) diameter was obtained from Pentacam HR. RESULTS 18 eyes from 11 subjects were analyzed. The topographic limbal diameter was 12.16 ± 0.68 mm (mean ± standard deviation) horizontally and 11.18 ± 0.65 mm vertically. The repeatability for the topographic limbal diameter was 0.054 mm. The internal and WTW horizontal limbal diameters were significantly smaller (linear mixed-effects model (GLMM), p <.017). The vertical internal limbal diameter was significantly larger (GLMM p <.05). The topographic limbus had significant ellipticity (0.25 ± 0.13 mm, wider horizontally, repeatability of 0.07 mm) and toricity (0.15 ± 0.08 mm, flatter horizontally, repeatability of 0.10 mm). Low coefficients of determination were found for the topographical limbus with the internal limbus (R2=0.021 and R2=0.039, for horizontal and vertical diameters respectively) and with the WTW (R2=0.146 for the horizontal diameter). CONCLUSION The proposed method to demarcate the 3D external topographical limbus is repeatable. The topographic limbal shape and size cannot be accurately derived from WTW nor internal limbus measures. This new technology may improve the process of scleral lens fitting.
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Affiliation(s)
- Clara Llorens-Quintana
- Casey Eye Institute and Department of Ophthalmology, Oregon Health and Science University, Portland, OR, USA
| | - Yan Li
- Casey Eye Institute and Department of Ophthalmology, Oregon Health and Science University, Portland, OR, USA
| | - Siyu Chen
- Casey Eye Institute and Department of Ophthalmology, Oregon Health and Science University, Portland, OR, USA
| | | | - David Huang
- Casey Eye Institute and Department of Ophthalmology, Oregon Health and Science University, Portland, OR, USA.
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Francis M, Matalia H, John AA, Matalia J, Chinnappaiah N, Bhandary P, Shetty R, Nuijts RMMA, Sinha Roy A. Minimum Corneal Diameter and Anterior Steep Axis Curvature Share the Same Meridian: A Novel Finding. Am J Ophthalmol 2023; 256:175-185. [PMID: 37669730 DOI: 10.1016/j.ajo.2023.08.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 08/25/2023] [Accepted: 08/25/2023] [Indexed: 09/07/2023]
Abstract
PURPOSE To define the external scleral sulcus (ESS) on a Scheimpflug image and use it for a morphometric analysis of corneal diameter (CD). DESIGN Retrospective, cross-sectional study of pediatric Asian-Indian eyes. METHODS One random eye of 353 subjects between 5 and 18 years underwent 25-scan Pentacam HR imaging. For all scans, densitometry values along the anterior corneal edge were recorded and differentiated. The peaks on the differentiated curve were chosen as the ESS points, and this distance between them was called CD. Vertical (vCD), maximum (maxCD), minimum (minCD) CD and their meridians were defined. Multiple regression models (MRMs) with CD and other Pentacam parameters were built to predict astigmatism and its axis, mean keratometry (Kmean), and Belin/Ambrósio enhanced ectasia display deviation (BAD-D). MRMs were validated using intraclass correlation coefficient (ICC). Estimated horizontal CD (hCD) was validated against digital caliper measurement using ICC. RESULTS The ICC (95% CI) between caliper and hCD was 0.96 (0.93, 0.97). MRM predictions (P < .001) used CD parameters, anterior chamber depth, corneal volume and distance from the corneal thinnest location to apex. These predictions achieved an ICC of 0.34 (0.18, 0.46), 0.82 (0.78, 0.86), 0.87 (0.84, 0.89), and 0.81 (0.76, 0.84), respectively. The astigmatism axis prediction depended on the minCD and maxCD meridians. Its within-subject SD (4.97°) was less than 2 consecutive Pentacam scan angles (7.2°). CONCLUSIONS The CD metric strongly correlated with the astigmatism axis, keratometry, and BAD-D. Its spatial description may be significant in corneal treatment planning and disease diagnoses.
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Affiliation(s)
- Mathew Francis
- From the Imaging, Biomechanics and Mathematical Modelling Solutions, Narayana Nethralaya Foundation (M.F., A.S.R.), Bangalore, India; Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India
| | - Himanshu Matalia
- Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India
| | - Ansu Ann John
- Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India
| | - Jyoti Matalia
- Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India
| | - Nandini Chinnappaiah
- Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India
| | - Prarthana Bhandary
- Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India
| | - Rohit Shetty
- Department of Corneal and Refractive Surgery, Narayana Nethralaya (H.M., A.A.J., J.M., N.C., P.B., R.S.), Bangalore, India; University Eye Clinic Maastricht, Maastricht University Medical Center (MUMC+) (M.F., R.S., R.M.M.A.N.), Maastricht, Netherlands
| | - Rudy M M A Nuijts
- University Eye Clinic Maastricht, Maastricht University Medical Center (MUMC+) (M.F., R.S., R.M.M.A.N.), Maastricht, Netherlands
| | - Abhijit Sinha Roy
- From the Imaging, Biomechanics and Mathematical Modelling Solutions, Narayana Nethralaya Foundation (M.F., A.S.R.), Bangalore, India.
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Consejo A, Roman DM, Roll V, Remon L. Relationship between corneal tissue and shape in short-term soft contact lens wear. Ophthalmic Physiol Opt 2023; 43:1372-1378. [PMID: 37551625 DOI: 10.1111/opo.13211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 08/09/2023]
Abstract
PURPOSE To investigate which morphometric and ocular surface tissue parameters are affected by short-term soft contact lens (CL) wear and to assess whether they carry related or independent information. METHODS Twenty-two healthy participants wore silicone hydrogel (SiHy; MyDay, CooperVision) soft CLs for 8 h in their left eye. Corneal tomography and corneoscleral topography were captured before and immediately after CL wear. Central corneal thickness (CCT), corneoscleral parameters (limbus position and corneoscleral junction [CSJ] angle) and corneal tissue parameters (corneal transparency and homogeneity) were evaluated. RESULTS Corneoscleral parameters (limbus position and CSJ angle) were independent of corneal tissue parameters (transparency and homogeneity) at baseline and after CL wear. CCT was independent of all the other parameters examined at baseline, but baseline values of corneal tissue parameters were moderately correlated with CCT change (transparency: r = -0.51; p = 0.007), homogeneity: r = -0.46; p = 0.02). CONCLUSIONS A complete characterisation of ocular surface changes following CL wear should consider corneoscleral topography and corneal densitometry simultaneously, since they carry complementary information.
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Affiliation(s)
- Alejandra Consejo
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
- Aragon Institute for Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
| | - Denisa M Roman
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
| | - Vanesa Roll
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
| | - Laura Remon
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
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Consejo A, Roll V, Roman DM, Remon L. The influence of soft contact lens material on the corneoscleral profile. Ophthalmic Physiol Opt 2023; 43:1364-1371. [PMID: 37376806 DOI: 10.1111/opo.13193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 05/30/2023] [Accepted: 06/13/2023] [Indexed: 06/29/2023]
Abstract
PURPOSE To objectively quantify changes in corneoscleral profile, as evaluated by the limbus position and corneoscleral junction (CSJ) angle, as a consequence of wearing different soft contact lens (CL) materials. METHODS Twenty-two healthy participants wore silicone hydrogel (SiHy, MyDay, CooperVision) and hydrogel (Hy, Biomedics 1 day extra, CooperVision) soft CLs for 8 h per lens in their left eye. In each session, corneoscleral topography was captured before and immediately after CL removal with an Eye Surface Profiler. Previously validated automatic and objective algorithms for limbal position and CSJ angle calculation were applied to 360 semi-meridians to investigate the effect of short-term CL wear on corneoscleral topography, globally and by sectors, depending on the soft CL material worn. RESULTS Short-term soft CL wear significantly impacted limbal position (SiHy: 120 ± 97 μm, Hy: 128 ± 85 μm) and CSJ angle (SiHy: 0.57 ± 0.36°, Hy: 0.55 ± 0.40°); all p < 0.05. A statistically significant difference was found between the sectors with regard to limbus position and CSJ angle before CL wear that remained following lens wear (all pairwise comparisons, p < 0.001). Although individual differences were observed, there was no evidence that one material caused more substantial corneoscleral alterations. CONCLUSION Corneoscleral profile parameters were altered significantly following 8 h of soft CL wear. The observed changes in limbus position and CSJ angle support the importance of participant-material biocompatibility.
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Affiliation(s)
- Alejandra Consejo
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
- Aragon Institute for Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
| | - Vanesa Roll
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
| | - Denisa M Roman
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
| | - Laura Remon
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
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Yam GHF, Pi S, Du Y, Mehta JS. Posterior corneoscleral limbus: Architecture, stem cells, and clinical implications. Prog Retin Eye Res 2023; 96:101192. [PMID: 37392960 DOI: 10.1016/j.preteyeres.2023.101192] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/22/2023] [Accepted: 06/23/2023] [Indexed: 07/03/2023]
Abstract
The limbus is a transition from the cornea to conjunctiva and sclera. In human eyes, this thin strip has a rich variation of tissue structures and composition, typifying a change from scleral irregularity and opacity to corneal regularity and transparency; a variation from richly vascularized conjunctiva and sclera to avascular cornea; the neural passage and drainage of aqueous humor. The limbal stroma is enriched with circular fibres running parallel to the corneal circumference, giving its unique role in absorbing small pressure changes to maintain corneal curvature and refractivity. It contains specific niches housing different types of stem cells for the corneal epithelium, stromal keratocytes, corneal endothelium, and trabecular meshwork. This truly reflects the important roles of the limbus in ocular physiology, and the limbal functionality is crucial for corneal health and the entire visual system. Since the anterior limbus containing epithelial structures and limbal epithelial stem cells has been extensively reviewed, this article is focused on the posterior limbus. We have discussed the structural organization and cellular components of the region beneath the limbal epithelium, the characteristics of stem cell types: namely corneal stromal stem cells, endothelial progenitors and trabecular meshwork stem cells, and recent advances leading to the emergence of potential cell therapy options to replenish their respective mature cell types and to correct defects causing corneal abnormalities. We have reviewed different clinical disorders associated with defects of the posterior limbus and summarized the available preclinical and clinical evidence about the developing topic of cell-based therapy for corneal disorders.
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Affiliation(s)
- Gary Hin-Fai Yam
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA; Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore; McGowan Institute for Regenerative Medicine, Pittsburgh, PA, USA.
| | - Shaohua Pi
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yiqin Du
- Department of Ophthalmology, University of South Florida, Tampa, FL, USA
| | - Jodhbir S Mehta
- Tissue Engineering and Cell Therapy Group, Singapore Eye Research Institute, Singapore; Department of Cornea and External Eye Disease, Singapore National Eye Centre, Singapore; Ophthalmology and Visual Sciences Academic Clinical Program, Duke-National University of Singapore (NUS) Medical School, Singapore.
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Consejo A, Rojas-Viñuela J, Sebastian-Carmona J, Ezpeleta J, Piñero DP. Corneoscleral junction angle in healthy eyes assessed objectively. Cont Lens Anterior Eye 2023; 46:101815. [PMID: 36725461 DOI: 10.1016/j.clae.2023.101815] [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: 09/27/2022] [Revised: 01/21/2023] [Accepted: 01/24/2023] [Indexed: 01/31/2023]
Abstract
PURPOSE To introduce a fully objective method to measure corneoscleral junction (CSJ) angle and evaluate the CSJ angle in healthy eyes. METHODS Corneoscleral topography (Eye Surface Profiler, ESP) was acquired from the right eye of 105 healthy Caucasian subjects, ranging from 18 to 59 years old. From the raw anterior eye height data, the topographic limbus was automatically demarcated in 360 semi-meridians. Further, in limbal location, the CSJ angle was automatically calculated from corneoscleral height data using neighbouring auxiliary points for angle calculation. Additionally, CSJ angle was statistically analysed regionally. RESULTS The mean CSJ angle was 177.5 ± 1.1°. There is a mean difference of 7.7 ± 3.7° between the steepest (smallest) and flattest (largest) CSJ angle within the same eye. There exist statistically significant differences between temporal (178.2 ± 1.4°) and nasal (176.4 ± 1.1°) regions (paired t-test, p < 0.001), and between superior (178.1 ± 1.1°) and inferior (177.9 ± 1.1°) regions (p = 0.038). CSJ angle is correlated with limbus position (r = 0.43, p < 0.001). CONCLUSION CSJ angle is rotationally asymmetric. CSJ varies regionally, being the smallest (steepest) in the nasal region. Significant rough changes in CSJ angle were observed for some healthy individuals.
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Affiliation(s)
- Alejandra Consejo
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain.
| | | | | | | | - David P Piñero
- Department of Ophthalmology, Vithas Medimar International Hospital, 03016 Alicante, Spain; Department of Optics, Pharmacology, and Anatomy, University of Alicante, Spain
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Niyazmand H, Read SA, Atchison DA. Repeatability of Anterior Eye Surface Topography Parameters from an Anterior Eye Surface Profilometer. Optom Vis Sci 2021; 98:1203-1209. [PMID: 34620781 DOI: 10.1097/opx.0000000000001789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
SIGNIFICANCE Anterior eye shape measurements are important for clinical contact lens fitting. The detailed assessment of measurement repeatability using the Eye Surface Profiler (ESP; Eaglet Eye B.V., AP Houten, the Netherlands) allows for more reliable interpretation of eye surface topography measurements. PURPOSE This study aimed to determine the repeatability of the ESP for anterior central corneal power and anterior eye surface height measurements. METHODS A Badal optometer was mounted on the ESP to provide an external fixation target with appropriate accommodation control and refractive correction. Forty-five healthy young adults underwent two sessions of anterior eye measurements, separated by 20 minutes, using the ESP. In each session, three consecutive scans were captured. Sagittal height data were obtained from 8-mm central cornea and from 8- to 14-mm diameter (encompassing the corneal periphery and anterior sclera). Anterior corneal powers were determined from the central cornea. Intersessional and intrasessional repeatability values were determined as coefficients of repeatability and root mean square error differences. RESULTS Sagittal height intersessional coefficients of repeatability for central nasal (5 μm) and central temporal (7 μm) were better than peripheral nasal (24 μm) and peripheral temporal (21 μm) regions. Sagittal height intrasessional coefficients of repeatability were 9, 8, 28, and 31 μm for central nasal, central temporal, peripheral nasal, and peripheral temporal regions, respectively. Intersessional coefficients of repeatability of mean sphere, 90/180° (J0) astigmatism, and oblique (J45) astigmatism were 0.67, 0.22, and 0.13 D, respectively, with corresponding intrasessional coefficients of repeatability of 1.27, 0.21, and 0.27 D. CONCLUSIONS The modified measuring procedure for the ESP used in this study provides highly repeatable sagittal height measurements in the central cornea but is less repeatable in the corneal periphery and scleral region. Results of the current study can be considered when using ESP in the interpretation of anterior eye surface shape measurements and in contact lens fitting and design.
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Affiliation(s)
| | - Scott A Read
- Contact Lens and Visual Optics Laboratory, Centre for Vision and Eye Research, School of Optometry and Vision Science, Kelvin Grove, Queensland University of Technology, Queensland, Australia
| | - David A Atchison
- Visual and Ophthalmic Optics Laboratory, Centre for Vision and Eye Research, School of Optometry and Vision Science, Kelvin Grove, Queensland University of Technology, Queensland, Australia
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Vanhonsebrouck E, Consejo A, Coucke PJ, Leroy BP, Kreps EO. The corneoscleral shape in Marfan syndrome. Acta Ophthalmol 2021; 99:405-410. [PMID: 32996688 DOI: 10.1111/aos.14636] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 07/07/2020] [Accepted: 09/02/2020] [Indexed: 12/12/2022]
Abstract
PURPOSE To investigate the corneoscleral shape in Marfan syndrome (MFS) patients. METHODS Thirty eyes of 15 participants with molecularly proven MFS were included in this prospective, cross-sectional study. Optical biometry, Scheimpflug imaging, and corneoscleral topography (Eye Surface Profiler) were performed in all patients. Topographic data were compared to data from controls (25 emmetropes and 17 myopes). The raw three-dimensional anterior height data from MFS eyes and control eyes were exported for further analysis. Custom-made software was used to demarcate the limbal radius and to calculate the sagittal height in different concentric annuli centred at the corneal apex, placed in a pupil plane, for the central cornea (0-4 mm radius), peripheral cornea (4-6 mm radius) and sclera (6-8 mm radius) and the corneoscleral asymmetry. RESULTS Marfan syndrome (MFS) eyes had significantly lower values of mean sagittal height compared to non-MFS eyes in all three annuli (central cornea, corneal periphery and sclera (independent t-test, p < 0.01 except for the inferior area of the scleral radius: p > 0.05). The sclera was significantly more asymmetric in MFS eyes compared to myopes (independent t-test, p < 0.01 for both eyes), but similar to emmetropes (independent t-test, p = 0.17 and p = 0.93 for right and left eyes, respectively). In MFS eyes, scleral asymmetry was not found to be correlated with axial length (Pearson correlation coefficient, r < 0.30, p > 0.05). CONCLUSION The peripheral cornea and sclera of Marfan syndrome patients have a significantly different shape compared to healthy controls.
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Affiliation(s)
| | - Alejandra Consejo
- Institute of Physical Chemistry Polish Academy of Sciences Warsaw Poland
| | - Paul J. Coucke
- Center for Medical Genetics Ghent University Hospital Ghent Belgium
| | - Bart P. Leroy
- Department of Ophthalmology Ghent University Hospital Ghent Belgium
- Center for Medical Genetics Ghent University Hospital Ghent Belgium
- Division of Ophthalmology & Center for Cellular & Molecular Therapeutics Children’s Hospital of Philadelphia Philadelphia USA
| | - Elke O. Kreps
- Department of Ophthalmology Ghent University Hospital Ghent Belgium
- Faculty of Medical Sciences Antwerp University Antwerp Belgium
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The corneoscleral shape in keratoconus patients with and without specialty lens wear. Cont Lens Anterior Eye 2021; 44:101343. [DOI: 10.1016/j.clae.2020.06.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/25/2020] [Accepted: 06/03/2020] [Indexed: 12/30/2022]
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10
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Bergmanson JP, Martinez JG. Size does matter: what is the corneo‐limbal diameter? Clin Exp Optom 2021; 100:522-528. [DOI: 10.1111/cxo.12583] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/01/2017] [Accepted: 06/14/2017] [Indexed: 11/30/2022] Open
Affiliation(s)
- Jan Pg Bergmanson
- Texas Eye Research and Technology Center,University of Houston College of Optometry, Houston, Texas, USA,
| | - Jesus G Martinez
- Texas Eye Research and Technology Center,University of Houston College of Optometry, Houston, Texas, USA,
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Comparison of Subjective and Objective Methods of Corneoscleral Limbus Identification from Anterior Segment Optical Coherence Tomography Images. Optom Vis Sci 2021; 98:127-136. [PMID: 33534377 DOI: 10.1097/opx.0000000000001637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
SIGNIFICANCE This study evaluates the reliability and validity of an automatic method of the external and internal limbal points identification from anterior segment optical coherence tomography (OCT) images in comparison with manual delineation. PURPOSE The purpose of this work was to evaluate the repeatability and precision of a previously proposed automatic method of external and internal limbal points identification and to compare them with the manual delineation by experienced clinicians in terms of limbus diameter. METHODS Optical coherence tomography tomograms obtained for 12 healthy volunteers without a history of eye diseases were analyzed. Fifteen OCT tomograms were captured for each patient. For all the images, the external and internal limbal points were determined using both the automatic and manual methods. The external and internal limbus diameters were used as the comparative parameter between the methods under consideration. The statistical analysis included mean, standard deviation, the Passing-Bablok regression, and the Pearson correlation coefficient. RESULTS A strong linear dependence between the automatic and manual methods was identified. While compared with the subjective estimates from clinicians, the automatic technique overestimated the external limbus diameter (bias equals 0.21 mm for optometrist and 0.23 mm for ophthalmologist) and slightly underestimated the internal limbus diameter (bias equals 0.13 mm for optometrist and 0.04 mm for ophthalmologist). The automatic method showed significantly better repeatability than the manual method in the case of external limbal points identification and comparably high repeatability for internal limbal points recognition. CONCLUSIONS Because of high precision and excellent repeatability, the automatic method of limbal points identification may be successfully used for estimation of the dynamic changes in the geometry of the anterior segment of the eye, where the large number of captured OCT images needs to be processed automatically with high precision.
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Bataille L, Piñero DP. Characterization of the geometric properties of the sclero-conjunctival structure: a review. Int J Ophthalmol 2020; 13:1484-1492. [PMID: 32953590 DOI: 10.18240/ijo.2020.09.22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 07/06/2020] [Indexed: 12/27/2022] Open
Abstract
To revise the peer-reviewed literature on geometric properties of the scleral-conjunctival structure in order to define their clinical relevance and the potential relationship between their changes and myopia development or progression. A bibliographic search focused on the study of the geometry of conjunctiva and/or sclera as well as those studies evaluating the relationship between geometric changes in the scleral-conjunctival structure and myopia was carried out. Several studies have been performed with different diagnostic technologies, including optical coherence tomography, profilometry and Scheimpflug imaging, to detect geometric changes of the scleral-conjunctival tissue in different physiological conditions of the eye, after use of contact lenses and in different ocular pathologies. Likewise, these technologies have been shown to be a valuable clinical tool to optimize scleral contact lens fitting. Future studies should investigate new potential clinical applications of such technologies, including the evaluation of anterior scleral changes related to myopia, as well as to define standardized clinical standard operating procedures for obtaining accurate and reproducible clinical measurement of the scleral-conjunctival morphology.
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Affiliation(s)
- Laurent Bataille
- Research and Development Department, VISSUM, Alicante 03016, Spain.,Group of Optics and Visual Perception, Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante 03690, Spain
| | - David P Piñero
- Group of Optics and Visual Perception, Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante 03690, Spain
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13
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Scleral shape and its correlation with corneal parameters in keratoconus. Cont Lens Anterior Eye 2020; 44:101366. [DOI: 10.1016/j.clae.2020.08.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 08/21/2020] [Accepted: 08/26/2020] [Indexed: 11/19/2022]
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14
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Anterior eye shape in emmetropes, low to moderate myopes, and high myopes. Cont Lens Anterior Eye 2020; 44:101361. [DOI: 10.1016/j.clae.2020.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Revised: 08/11/2020] [Accepted: 08/11/2020] [Indexed: 12/13/2022]
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15
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Niyazmand H, Read SA, Atchison DA, Collins MJ. Effects of accommodation and simulated convergence on anterior scleral shape. Ophthalmic Physiol Opt 2020; 40:482-490. [DOI: 10.1111/opo.12697] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 05/07/2020] [Indexed: 12/15/2022]
Affiliation(s)
- Hamed Niyazmand
- Contact Lens and Visual Optics Laboratory Institute of Health & Biomedical Innovation School of Optometry and Vision Science Queensland University of Technology Brisbane Australia
| | - Scott A Read
- Contact Lens and Visual Optics Laboratory Institute of Health & Biomedical Innovation School of Optometry and Vision Science Queensland University of Technology Brisbane Australia
| | - David A Atchison
- Visual and Ophthalmic Optics Laboratory Institute of Health & Biomedical Innovation School of Optometry and Vision Science Queensland University of Technology Brisbane Australia
| | - Michael J Collins
- Contact Lens and Visual Optics Laboratory Institute of Health & Biomedical Innovation School of Optometry and Vision Science Queensland University of Technology Brisbane Australia
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Krzyżanowska-Berkowska P, Czajor K, Syga P, Iskander DR. Lamina Cribrosa Depth and Shape in Glaucoma Suspects. Comparison to Glaucoma Patients and Healthy Controls. Curr Eye Res 2019; 44:1026-1033. [PMID: 31117833 DOI: 10.1080/02713683.2019.1616767] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Purpose: To evaluate the lamina cribrosa depth and shape parameters in glaucoma suspects compared to glaucoma patients and healthy controls. Materials and Methods: A total of 325 subjects (120 with primary open-angle glaucoma, 103 glaucoma suspects and 102 healthy controls) were included. Serial horizontal B-scan images of optic nerve head were obtained using enhanced depth imaging of the optical coherence tomography. For each of the 325 subjects, lamina cribrosa position was measured manually in 16 horizontal B-scans, hence 5200 scans in total were analyzed. In particular, lamina cribrosa depth (LCD), lamina cribrosa deflection depth (LCDD), lamina cribrosa shape index (LCSI), and its horizontal equivalent (LCSIH) were estimated. Along lamina cribrosa parameterization, intraocular pressure, visual field, central retinal thickness, retinal nerve fiber layer thickness, and disc and neuroretinal rim areas were also measured. Results: LCD was statistically significant different (P < .001) in glaucoma patients when compared to glaucoma suspects and heathy controls (603 ± 172 μm versus 554 ± 114 μm and 531 ± 115 μm, respectively). Similarly, LCDD was statistically significant different (P < .001) in glaucoma patients when compared to glaucoma suspects and heathy controls (250 ± 78 μm versus 213 ± 54 μm and 211 ± 58 μm, respectively). No statistically significant differences were found in LCSI (P = .957). However, LCSIH showed statistically significant differences between healthy controls and glaucoma suspects (P = .003) and between healthy controls and glaucoma patients (P = .006). Conclusions: The deformation of LC in glaucoma suspects, in terms of LCSIH, was not statistically different from that of glaucoma patients. LCD does not have the potential to discriminate glaucoma suspects from healthy controls.
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Affiliation(s)
| | - Karolina Czajor
- Department of Ophthalmology, Wroclaw Medical University , Wroclaw , Poland
| | - Piotr Syga
- Department of Computer Science, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology , Wroclaw , Poland
| | - D Robert Iskander
- Department of Biomedical Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology , Wroclaw , Poland
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Characterization of Corneoscleral Geometry Using Fourier Transform Profilometry in the Healthy Eye. Eye Contact Lens 2019; 45:201-207. [DOI: 10.1097/icl.0000000000000560] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Macedo-de-Araújo RJ, van der Worp E, González-Méijome JM. In vivo assessment of the anterior scleral contour assisted by automatic profilometry and changes in conjunctival shape after miniscleral contact lens fitting. JOURNAL OF OPTOMETRY 2019; 12:131-140. [PMID: 30393001 PMCID: PMC6449784 DOI: 10.1016/j.optom.2018.10.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/17/2018] [Accepted: 10/01/2018] [Indexed: 06/08/2023]
Abstract
PURPOSE To compare the shape of the anterior sclera of candidates to scleral lens (ScCL) fitting with regular and irregular corneas and analyze the changes induced in the shape of the sclero-conjunctiva after ScCL wear. METHODS Thirty-five eyes of 18 subjects (19 eyes with irregular corneas and 16 with regular corneas) were consecutively recruited. Three measures of sclero-conjunctival shape were taken with Eye Surface Profiler (ESP, Eaglet Eye, Houten, The Netherlands). Tangent angles and ocular sagittal heights (OC-SAG) were analyzed at different chords from 13 to 17mm in the nasal, temporal, superior and inferior regions. The 19 eyes with irregular cornea were selected to wear ScCL and the changes in their sclero-conjunctival surface parameters were compared before and after 3h of lens wear. RESULTS Irregular corneas showed higher OC-SAG values than regular corneas in all the chords analyzed, with statistical significant differences in the temporal region. Regarding tangent angles, regular corneas showed lower values (flatter surface), with statistical significant differences at 8 and 8.50mm on the nasal and 8.50mm on the temporal region. Some changes were seen in sclero-conjuctival shape after short-term ScCL wear. There was an augment in OC-SAG after 3h of scleral lens wear and a reduction on tangent angles, namely on the nasal region at 7.5mm and 8.00mm chord lengths, which is coincidental with the landing zone of ScCL. CONCLUSIONS ESP shows mild differences in scleral shape between eyes with regular and irregular corneas. ESP might be valuable in quantifying the mechanical impact of the ScCL on the anterior eye surface.
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Affiliation(s)
| | - Eef van der Worp
- Eye-Contact-Lens Research & Education, Amsterdam, The Netherlands
| | - José Manuel González-Méijome
- Clinical & Experimental Optometry Research Lab (CEORLab), Center of Physics, University of Minho, Braga, Portugal
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Anterior eye surface changes following miniscleral contact lens wear. Cont Lens Anterior Eye 2019; 42:70-74. [DOI: 10.1016/j.clae.2018.06.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/22/2018] [Accepted: 06/25/2018] [Indexed: 12/16/2022]
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20
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Differences in corneo-scleral topographic profile between healthy and keratoconus corneas. Cont Lens Anterior Eye 2019; 42:75-84. [DOI: 10.1016/j.clae.2018.05.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 05/11/2018] [Accepted: 05/17/2018] [Indexed: 11/20/2022]
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Abass A, Lopes BT, Eliasy A, Wu R, Jones S, Clamp J, Ambrósio R, Elsheikh A. Three-dimensional non-parametric method for limbus detection. PLoS One 2018; 13:e0207710. [PMID: 30475843 PMCID: PMC6261009 DOI: 10.1371/journal.pone.0207710] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/03/2018] [Indexed: 12/12/2022] Open
Abstract
Purpose To present a novel non-parametric algorithm for detecting the position of the human eye limbus in three dimensions and a new dynamic method for measuring the full 360° visible iris boundary known as white-to-white distance along the eye horizontal line. Methods The study included 88 participants aged 23 to 65 years (37.7±9.7), 47 females and 41 males. Clinical characteristics, height data and the apex coordinates and 1024×1280 pixel digital images of the eyes were taken by an Eye Surface Profiler and processed by custom-built MATLAB codes. A dynamic light intensity frequency based white-to-white detection process and a novel three-dimensional method for limbus detection is presented. Results Evidence of significant differences (p<0.001) between nasal-temporal and superior-inferior white-to-white distances in both right and left eyes were found (nasal-temporal direction; 11.74±0.42 mm in right eyes and 11.82±0.47 mm in left eyes & superior-inferior direction; 11.52±0.45 mm in right eyes and 11.55±0.46 mm in left eyes). Average limbus nasal-temporal diameters were 13.64±0.55 mm for right eyes, and 13.74±0.40 mm for left eyes, however the superior-inferior diameters were 13.65±0.54 mm, 13.75±0.38 mm for right and left eyes, respectively. No significant difference in limbus contours has been observed either between the nasal-temporal direction (p = 0.91) and the superior-inferior direction (p = 0.83) or between the right (p = 0.18) and left eyes (p = 0.16). Evidence of tilt towards the nasal-temporal side in the three-dimensional shape of the limbus was found. The right eyes mean limbus contour tilt around the X-axis was -0.3±1.35° however, their mean limbus contour tilt around the Y-axis was 1.76±0.9°. Likewise, the left eyes mean limbus contour tilt around the X-axis was 0.77±1.25° and the mean limbus contour tilt around the Y-axis was -1.54±0.89°. Conclusions The white-to-white distance in the human eye is significantly larger in the nasal-temporal direction than in the superior-inferior direction. The human limbus diameter was found not to vary significantly in these directions. The 3D measures show that the limbus contour does not lay in one plane and tends to be higher on the nasal-inferior side of the eye.
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Affiliation(s)
- Ahmed Abass
- School of Engineering, University of Liverpool, Liverpool, United Kingdom
| | - Bernardo T Lopes
- School of Engineering, University of Liverpool, Liverpool, United Kingdom.,Federal University of São Paulo, São Paulo, Brazil
| | - Ashkan Eliasy
- School of Engineering, University of Liverpool, Liverpool, United Kingdom
| | - Richard Wu
- Central Taiwan University of Science and Technology, Taichung, Taiwan.,Pacific University, College of Optometry, Forest Grove, Oregon, United States of America
| | - Steve Jones
- School of Engineering, University of Liverpool, Liverpool, United Kingdom
| | - John Clamp
- UltraVision CLPL, Leighton Buzzard, United Kingdom
| | | | - Ahmed Elsheikh
- School of Engineering, University of Liverpool, Liverpool, United Kingdom.,National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
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Consejo A, Behaegel J, Van Hoey M, Iskander DR, Rozema JJ. Scleral asymmetry as a potential predictor for scleral lens compression. Ophthalmic Physiol Opt 2018; 38:609-616. [DOI: 10.1111/opo.12587] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 10/16/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Alejandra Consejo
- Department of Ophthalmology; Antwerp University Hospital; Edegem Belgium
- Department of Medicine and Health Sciences; University of Antwerp; Antwerp Belgium
- Department of Biomedical Engineering; Wroclaw University of Science and Technology; Wroclaw Poland
| | - Joséphine Behaegel
- Department of Medicine and Health Sciences; University of Antwerp; Antwerp Belgium
- Department of Ophthalmology; Brussels University Hospital; Jette Belgium
| | - Maarten Van Hoey
- Department of Ophthalmology; Antwerp University Hospital; Edegem Belgium
| | - D Robert Iskander
- Department of Biomedical Engineering; Wroclaw University of Science and Technology; Wroclaw Poland
| | - Jos J Rozema
- Department of Ophthalmology; Antwerp University Hospital; Edegem Belgium
- Department of Medicine and Health Sciences; University of Antwerp; Antwerp Belgium
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The influence of limbal and scleral shape on scleral lens design. Cont Lens Anterior Eye 2018; 41:321-328. [DOI: 10.1016/j.clae.2018.02.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/19/2018] [Accepted: 02/20/2018] [Indexed: 11/18/2022]
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Corneo-scleral limbal changes following short-term soft contact lens wear. Cont Lens Anterior Eye 2017; 40:293-300. [PMID: 28550975 DOI: 10.1016/j.clae.2017.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 04/28/2017] [Accepted: 04/28/2017] [Indexed: 12/25/2022]
Abstract
PURPOSE To assess whether short-term soft contact lens wear alters the anterior eye surface. METHODS Twenty-two neophyte subjects wore soft contact lenses for a period of five hours. Topography based corneo-scleral limbal radius estimates were derived from height measurements acquired with a corneo-scleral profilometer. Additionally, central corneal thickness (CCT), anterior chamber depth (ACD), corneal curvature radius (R) and white-to-white (WTW) diameter were acquired with an OCT-assisted biometer. Measurements were obtained without lens wear (baseline), immediately after lens removal following five hours of wear and three hours after lens removal. RESULTS Short-term soft contact lens wear significantly modifies corneo-scleral limbal radius (mean±SD: 130±74μm, p << 0.001) and the changes are repeatable. In contrast, the WTW diameter and R were not modified. ACD and CCT were significantly affected but no significant correlations were found between the increment of the limbal radius and the decrease in ACD and CCT. Limbal radius increment was reversed three hours after lens removal for 68% of the subjects but the time course of this reversal was not uniform. CONCLUSIONS It is possible to accurately quantify limbal radius changes as a consequence of soft contact lens wear. The increment in the limbal diameter could reach over 0.5mm but that alteration does not correspond to changes in WTW diameter and it was not observable to the examiner using a slit lamp. Assessing topographical limbus after contact lens wear could be a tool to optimize the selection of the contact lens, from the perspective of anterior eye surface changes.
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Consejo A, Llorens-Quintana C, Radhakrishnan H, Iskander RD. Mean shape of the human limbus. J Cataract Refract Surg 2017; 43:667-672. [DOI: 10.1016/j.jcrs.2017.02.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 01/17/2017] [Accepted: 02/24/2017] [Indexed: 10/19/2022]
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Scleral changes with accommodation. Ophthalmic Physiol Opt 2017; 37:263-274. [DOI: 10.1111/opo.12377] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 02/21/2017] [Indexed: 11/26/2022]
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