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Fisher D, Collins MJ, Vincent SJ. The effect of lens and fitting characteristics upon scleral lens centration. Ophthalmic Physiol Opt 2024. [PMID: 39033320 DOI: 10.1111/opo.13367] [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: 05/06/2024] [Revised: 07/09/2024] [Accepted: 07/11/2024] [Indexed: 07/23/2024]
Abstract
PURPOSE To quantify the impact of varying central fluid reservoir depth, lens thickness/mass and the addition of a peripheral fenestration upon scleral lens centration. METHODS Ten young, healthy adults participated in a series of repeated-measures experiments involving short-term (90 min) open eye scleral lens wear. Scleral lens parameters (material, back optic zone radius, diameter, back vertex power and landing zone) were controlled across all experiments, and the central fluid reservoir depth (ranging from 144 to 726 μm), lens thickness (ranging from 150 to 1200 μm), lens mass (101-241 mg) and lens design (with or without a single 0.3 mm peripheral fenestration) were altered systematically. Scleral lens decentration was quantified using over-topography maps. RESULTS On average, scleral lens centration varied by <0.10 mm over 90 min of wear. Medium and high initial fluid reservoir conditions resulted in 0.17 mm more temporal and 0.55 mm more inferior lens decentration, compared to the low fluid reservoir depth (p < 0.001). Changes in lens thickness or the addition of a peripheral fenestration did not cause clinically significant changes in centration (<0.10 mm on average) when controlling for fluid reservoir depth. Central fluid reservoir depth was the best predictor of horizontal and vertical lens decentration, explaining 62-73% of the observed variation, compared to 40-44% for lens thickness and mass. CONCLUSION Scleral lens decentration remained relatively stable over 90 min of lens wear. A greater initial central fluid reservoir depth resulted in significantly more lens decentration, particularly inferiorly. Large variations in lens thickness, mass or the addition of a single peripheral fenestration did not substantially affect lens centration.
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Affiliation(s)
- Damien Fisher
- Contact Lens and Visual Optics Laboratory, Queensland University of Technology, Optometry and Vision Science, Centre for Vision and Eye Research, Brisbane, Queensland, Australia
| | - Michael J Collins
- Contact Lens and Visual Optics Laboratory, Queensland University of Technology, Optometry and Vision Science, Centre for Vision and Eye Research, Brisbane, Queensland, Australia
| | - Stephen J Vincent
- Contact Lens and Visual Optics Laboratory, Queensland University of Technology, Optometry and Vision Science, Centre for Vision and Eye Research, Brisbane, Queensland, Australia
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Alexander J, Belaineh Aweke Y, Bhebhe Z, Cho D, Lay S, Ryan I, Collins MJ, Vincent SJ. The effect of landing zone toricity on scleral lens fitting characteristics and optics. Ophthalmic Physiol Opt 2024; 44:867-875. [PMID: 38699941 DOI: 10.1111/opo.13324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 04/10/2024] [Accepted: 04/18/2024] [Indexed: 05/05/2024]
Abstract
PURPOSE The fit and optical performance of a scleral lens is affected by the alignment of the landing zone with the underlying ocular surface. The aim of this research was to quantify the effect of landing zone toricity upon scleral lens fitting characteristics (rotation and decentration) and optics (lens flexure) during short-term wear. METHODS Scleral lenses with nominal landing zone toricities of 0, 100, 150 and 200 μm were worn in a randomised order by 10 young healthy participants (mean [SD] 24 [7] years) for 30 min, with other lens parameters held constant. Scleral toricity was quantified using a corneo-scleral profilometer, and lens flexure, rotation, and decentration were quantified using over-topography during lens wear. Repeated measures analyses were conducted as a function of landing zone toricity and residual scleral toricity (the difference between scleral and lens toricity) for eyes with 'low' magnitude scleral toricity (mean: 96 μm) and 'high' magnitude scleral toricity (mean: 319 μm). RESULTS Toric landing zones significantly reduced lens flexure (by 0.37 [0.21] D, p < 0.05) and lens rotation (by 20 [24]°, p < 0.05) compared with a spherical landing zone. Horizontal and vertical lens decentration did not vary significantly with landing zone toricity. These trends for flexure, rotation, and decentration were also observed for eyes with 'low' and 'high' magnitude scleral toricity as a function of residual scleral toricity. CONCLUSION Landing zones with 100-200 μm toricity significantly reduced lens flexure (by ~62%) and rotation (by ~77%) but not horizontal or vertical lens decentration, compared with a spherical landing zone, when controlling for other confounding variables. The incorporation of a toric landing zone, even for eyes with lower magnitude scleral toricity (~100 μm), may be beneficial, particularly for front surface optical designs.
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Affiliation(s)
- Julian Alexander
- Optometry & Vision Science, Centre for Vision & Eye Research, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Yabkal Belaineh Aweke
- Optometry & Vision Science, Centre for Vision & Eye Research, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Zibonele Bhebhe
- Optometry & Vision Science, Centre for Vision & Eye Research, Queensland University of Technology, Brisbane, Queensland, Australia
| | - David Cho
- Optometry & Vision Science, Centre for Vision & Eye Research, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Steven Lay
- Optometry & Vision Science, Centre for Vision & Eye Research, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Isaac Ryan
- Optometry & Vision Science, Centre for Vision & Eye Research, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Michael J Collins
- Optometry & Vision Science, Centre for Vision & Eye Research, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Stephen J Vincent
- Optometry & Vision Science, Centre for Vision & Eye Research, Queensland University of Technology, Brisbane, Queensland, Australia
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Martínez-Plaza E, López-de la Rosa A, Molina-Martín A, Piñero DP. Orthokeratology effect on the corneoscleral profile: Beyond the bull's eye. Ophthalmic Physiol Opt 2024; 44:757-768. [PMID: 38240175 DOI: 10.1111/opo.13279] [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: 09/05/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 05/01/2024]
Abstract
PURPOSE To assess the impact of 3 months of orthokeratology (ortho-k) contact lenses (CLs) for myopia correction on the corneoscleral profile, as changes in scleral geometry could serve as indirect evidence of alteration in the corneal biomechanical properties. METHODS Twenty subjects (40 eyes) were recruited to wear ortho-k lenses overnight; however, after discontinuation (two CL fractures, one under-correction and two non-serious adverse events), 16 subjects (31 eyes) finished a 3-month follow-up. Corneoscleral topographies were acquired using the Eye Surface Profiler (ESP) system before and after 3 months of lens wear. Steep (SimKs) and flat (SimKf) simulated keratometry and scleral sagittal height measurements for 13-, 14- and 15-mm chord lengths were automatically calculated by the ESP software. Additionally, sagittal height and slope were calculated in polar format from 21 radii (0-10 mm from the corneal apex) at 12 angles (0-330°). Linear mixed models were fitted to determine the differences between visits. RESULTS SimKs and SimKf were increased significantly (p ≤ 0.02). The sagittal height in polar format increased significantly (p = 0.046) at a radius of 2.5 mm for 150°, 180°, 210° and 240° orientations and at a radius of 3.0 mm for 210°. Additionally, the slope in polar format significantly decreased (p ≤ 0.04) at radii ranges of 0.0-0.5, 0.5-1.0 and 1.0-1.5 mm for multiple angles and at a radii range of 5.0-5.5 mm for 90°. It also increased significantly (p ≤ 0.045) at a radii range of 1.5-2.0 mm for 30° and at radii ranges of 2.0-2.5, 2.5-3.0 and 3.0-3.5 mm for multiple angles. No significant changes were found for any parameter measured from the scleral area. CONCLUSIONS Three months of overnight ortho-k lens wear changed the central and mid-peripheral corneal geometry as expected, maintaining the peripheral cornea and the surrounding sclera stability.
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Affiliation(s)
- Elena Martínez-Plaza
- Group of Optics and Visual Perception, Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
- University of Valladolid, Valladolid, Spain
| | - Alberto López-de la Rosa
- Department of Theoretical Physics, Atomic and Optics, University of Valladolid, Valladolid, Spain
- Instituto de Oftalmobiología Aplicada (IOBA), University of Valladolid, Valladolid, Spain
| | - Ainhoa Molina-Martín
- Group of Optics and Visual Perception, Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - David P Piñero
- Group of Optics and Visual Perception, Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
- Department of Ophthalmology, Vithas Medimar International Hospital, Alicante, Spain
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Ballet B, Behaegel J, Reppe S, Consejo A, Aass HC, Utheim TP, Koppen C, Ní Dhubhghaill S. Ocular Surface Homeostasis After Scleral Lens Usage. Eye Contact Lens 2023; 49:459-463. [PMID: 37651199 DOI: 10.1097/icl.0000000000001027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2023] [Indexed: 09/02/2023]
Abstract
OBJECTIVES The aim of this prospective study is to examine the effects of 5 hours of well-fitted, mini-scleral contact lens (mini-SL) wear on the tear film cytokine expression in healthy eyes. METHODS Twenty-three healthy participants were included in the study. One eye of each participant was selected at random, and a mini-SL measuring 16.5 mm in diameter was fitted by an experienced contact lens specialist. The contact lens remained in place for 5 hours. Precorneal tear fluid was collected using capillary tubes at three different time points: baseline before SL insertion (T0), after 5 hours of SL wear (T1), and 3 hours after SL removal (T2). The concentration of 40 inflammatory cytokines at the three different time points was determined using multiplex bead assay. RESULTS Mini-scleral lens wear did not result in significant changes in the cytokine-to-protein ratio after 5 hours of wear on a healthy eye. CONCLUSIONS Although a well-fitted mini-SL reduces the rate at which the precorneal tear film is refreshed, 5 hours of lens wear did not appear to significantly affect the tears cytokine-to-protein ratio, suggesting that scleral lenses have minimal impact on corneal cytokine expression.
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Affiliation(s)
- Brice Ballet
- Department of Ophthalmology (B.B., J.B., C.K., S.N.D.), Antwerp University Hospital, Edegem, Belgium; Faculty of Medicine and Health Sciences (B.B., C.K., S.N.D.), University of Antwerp, Wilrijk, Belgium; Department of Medical Biochemistry (S.R., H.C.A., T.P.U.), Oslo University Hospital, Oslo, Norway; Department of Plastic and Reconstructive Surgery (S.R., T.P.U.), Oslo University Hospital, Oslo, Norway; and Department of Applied Physics (A.C.), 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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Bergmann B, Wolffsohn JS, Bandlitz S. Scheimpflug imaging for grading and measurement of corneo-scleral-profile in different quadrants. Cont Lens Anterior Eye 2023; 46:101753. [PMID: 36030150 DOI: 10.1016/j.clae.2022.101753] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 08/15/2022] [Accepted: 08/16/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE The corneo-scleral-profile (CSP) describes the transition from cornea to sclera, while the corneo-scleral junction angle (CSJ), is the angle formed between the cornea and the sclera. The aims of this study were (i) to analyse the CSP and CSJ in different quadrants and (ii) to test correlation and repeatability of an established observational grading and measurement method, using Scheimpflug images. METHODS The nasal, temporal, superior and inferior CSP of 35 healthy eye participants (mean age 25.5 SD ± 3.1 years; 20 female) was imaged using the corneo-scleral-profile module of the Pentacam (Oculus, Wetzlar, Germany). On the captured Scheimpflug images CSP was subjectively graded into five different corneo-scleral transitions, using the Meier grading scale (profile 1 fluid-convex; profile 2 fluid-tangential; profile 3 marked-convex; profile 4 marked-tangential; profile 5 concave). The CSJ was measured on the same images using ImageJ v1.8.0. Grading and measurement was repeated at a second session. Intra-observer reliability for the CSP-grading was analysed by Cohen's Kappa. Differences between repeated CSJ-measurements and different quadrants were analysed by paired-t-test and ANOVA. The eta-coefficient was used to determine the association between subjective CSP-grading and CSJ-measurement. RESULTS Intra-observer reliability for the CSP grading system was poor (kappa = 0.098) whereas repeated measurements of CSJ angle showed no statistically significant difference between sessions (0.04°; 95 % CI - 0.21° to 0.29°; p = 0.77). CSJ angles ranged from 172° to 180° with no statistically significant differences between nasal, temporal, superior and inferior (p = 0.24). Eta-coefficient indicated a weak association between CSP-grading and CSJ-measurement (η = 0.27; p = 0.04). CONCLUSIONS The subjective CSP-grading showed poorer repeatability than the objective CSJ-measurement, which did not detect any differences in angles between the meridians. The weak association between CSP-grading and CSJ-measurement is likely caused by the limited intra-observer reliability of the Meier grading scale. Furthermore, the CSP-grading scale seems to consider other aspects beside the CSJ angle, such as scleral radius.
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Affiliation(s)
- Benjamin Bergmann
- Höhere Fachschule für Augenoptik Köln, Cologne School of Optometry, Cologne, Germany
| | - James S Wolffsohn
- School of Health and Life Sciences, Aston University, Birmingham, United Kingdom
| | - Stefan Bandlitz
- Höhere Fachschule für Augenoptik Köln, Cologne School of Optometry, Cologne, Germany; School of Health and Life Sciences, Aston University, Birmingham, United Kingdom.
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Consejo A, Trillo-Moreno I, Remon L. Corneal tissue changes following short-term soft contact lens wear of different materials. Ophthalmic Physiol Opt 2023; 43:35-45. [PMID: 36408647 PMCID: PMC10099478 DOI: 10.1111/opo.13067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 10/11/2022] [Accepted: 10/24/2022] [Indexed: 11/22/2022]
Abstract
PURPOSE To study the effect of different soft contact lens (CL) materials during short-term wear on corneal tissue. METHODS Twenty-two healthy participants wore both silicone hydrogel (MyDay, CooperVision) and hydrogel soft CLs (Biomedics 1 day extra, CooperVision) for 8 h per lens. In each session, Scheimpflug images were captured before and immediately after CL removal. Images were analysed using the densitometry distribution analysis, a technique from which two parameters, α (corneal transparency) and β (corneal homogeneity), were estimated. In addition, the central corneal thickness changes after CL wear and the influence of the CL material on corneal transparency were evaluated. RESULTS The β parameter (homogeneity) increased by 5% after wearing both CL materials (paired t-test, p < 0.001). However, the α parameter (transparency) only increased in half of the participants. No material was found to be more determinant in causing the corneal densitometry changes. Statistically significant but not clinically relevant changes in corneal thickness were observed. CONCLUSIONS Biomarkers of corneal tissue integrity (α and β) were affected by short-term soft contact lens wear. The observed changes in corneal transparency and homogeneity were not clinically relevant but support the importance of participant-material biocompatibility.
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Affiliation(s)
- Alejandra Consejo
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
| | | | - Laura Remon
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
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Rozema JJ, Hastings GD, Jiménez-García M, Koppen C, Applegate RA. Influence of rigid lens decentration and rotation on visual image quality in normal and keratoconic eyes. Ophthalmic Physiol Opt 2022; 42:1204-1213. [PMID: 36111637 PMCID: PMC9547948 DOI: 10.1111/opo.13045] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/05/2022] [Accepted: 08/07/2022] [Indexed: 10/25/2023]
Abstract
PURPOSE To investigate whether the movement of a rigid sphero-cylindrical contact lens has a greater impact on the visual image quality in highly aberrated eyes than in normal eyes. METHODS For 20 normal and 20 keratoconic SyntEyes, a previously determined best sphero-cylindrical rigid lens was permitted to shift by up to ±1 mm from the line of sight and rotate up to ±15°. Each of the 52,111 lens locations sampled was ray-traced to determine the influence on the wavefront aberration. In turn, the logarithm of visual Strehl ratio (log10 [VSX]) was calculated for each aberration structure and was used to estimate the associated changes in logMAR visual acuity. Finally, contour surfaces of two-letter change in visual acuity were plotted in three-dimensional misalignment space, consisting of decentrations in the x and y directions and rotation, and volumes within these surfaces were calculated. RESULTS The variations in image quality within the misalignment space were unique to each eye. A two-letter loss was generally reached with smaller misalignments in keratoconic eyes (10.5 ± 4.7° of rotation or 0.27 ± 0.13 mm of shift) than in normal eyes (13.4 ± 1.8° and 0.39 ± 0.15 mm, respectively) due to larger cylindrical errors. For keratoconic eyes, on average, 14.4 ± 14.9% of misalignment space saw VSX values above the lower normal VSX threshold, well below the values of normal eyes of 48.5 ± 18.5%. In some eyes, a specific combination of lens shift and lens rotation away from the line of sight leads to a simulated improvement in visual image quality. CONCLUSION Variations in visual image quality due to the misalignment of rigid sphero-cylindrical contact lens corrections are larger for keratoconic eyes than for normal eyes. In some cases, a specific misalignment may improve visual image quality, which could be considered in the design of the next generation of rigid contact lenses.
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Affiliation(s)
- Jos J Rozema
- Visual Optics Lab Antwerp (VOLANTIS), Faculty of Medicine and Health Sciences, Antwerp University, Wilrijk, Belgium
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium
| | - Gareth D Hastings
- College of Optometry, University of Houston, Houston, Texas, USA
- Center for Innovation in Optics and Vision, School of Optometry, University of California, Berkeley, California, USA
| | - Marta Jiménez-García
- Visual Optics Lab Antwerp (VOLANTIS), Faculty of Medicine and Health Sciences, Antwerp University, Wilrijk, Belgium
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium
| | - Carina Koppen
- Visual Optics Lab Antwerp (VOLANTIS), Faculty of Medicine and Health Sciences, Antwerp University, Wilrijk, Belgium
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium
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Kumar M, Shetty R, Lalgudi VG, Roy AS, Khamar P, Vincent SJ. Corneal Biomechanics and Intraocular Pressure Following Scleral Lens Wear in Penetrating Keratoplasty and Keratoconus. Eye Contact Lens 2022; 48:206-209. [PMID: 35333810 DOI: 10.1097/icl.0000000000000886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/11/2021] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To compare corneal biomechanics and intraocular pressure (IOP) in keratoconus and penetrating keratoplasty eyes before and after nonfenestrated scleral lens wear. METHODS Twenty-three participants were enrolled, and 37 eyes were included in the analysis (11 penetrating keratoplasty and 26 keratoconus). A range of corneal biomechanical parameters and IOP were measured using the CORVIS ST before and after 8 hr of nonfenestrated scleral lens wear (Keracare, Acculens, Denver, CO). RESULTS Before lens wear, penetrating keratoplasty eyes displayed significantly greater median values for central corneal thickness (97 μm thicker, P=0.02), IOP (3.89 mm Hg higher, P=0.01), and biomechanical parameter A2 length (0.48 mm longer, P=0.003) compared with keratoconic eyes. No significant changes in corneal biomechanical parameters or IOP were observed after scleral lens wear in either group (all P>0.05). CONCLUSION Although nonfenestrated scleral contact lenses can induce a subatmospheric pressure after lens settling and compress tissue surrounding the limbus, no significant changes were detected in the corneal biomechanical parameters studied using CORVIS ST after scleral lens wear in eyes with penetrating keratoplasty and keratoconus.
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Affiliation(s)
- Mukesh Kumar
- Narayana Nethralaya (M.K., R.S., V.G.L., A.S.R., P.K.), Bangalore, India; and Centre for Vision and Eye Research (S.J.V.), School of Optometry & Vision Science, Queensland University of Technology, Brisbane, Australia
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Macedo-de-Araújo RJ, Fadel D, Barnett M. How Can We Best Measure the Performance of Scleral Lenses? Current Insights. CLINICAL OPTOMETRY 2022; 14:47-65. [PMID: 35418790 PMCID: PMC9000539 DOI: 10.2147/opto.s284632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 03/24/2022] [Indexed: 06/14/2023]
Abstract
Scleral lenses (SLs) present several unique advantageous characteristics for patients. As these lenses are mainly fitted in severely diseased eyes, a thorough evaluation of the ocular surface before and after SL fitting and the on-eye SL fitting evaluation are essential and help minimize potential physiological complications. This review will explore the current and emerging techniques and instrumentation to best measure SL performance ensuring optimal lens fitting, visual quality, comfort and physiological responses, highlighting some potential complications and follow-up recommendations. A single physician could perform the great majority of evaluations. Still, the authors consider that the assessment of SL fitting should be a collaborative and multidisciplinary job, involving contact lens practitioners, ophthalmologists and the industry. This publication has reviewed the most up-to-date work and listed the most used techniques; however, the authors encourage the development of more evidence-based recommendations for SL clinical practice.
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Affiliation(s)
- Rute J Macedo-de-Araújo
- Clinical & Experimental Optometry Research Laboratory (CEORLab), Physics Centre of Minho and Porto Universities (CF-UM-UP), University of Minho, Braga, Portugal
| | | | - Melissa Barnett
- Davis Eye Center, University of California, Sacramento, CA, USA
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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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13
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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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Corneoscleral Topography Measured with Fourier-based Profilometry and Scheimpflug Imaging. Optom Vis Sci 2021; 97:766-774. [PMID: 32941338 DOI: 10.1097/opx.0000000000001572] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
SIGNIFICANCE Precise measurement of corneoscleral topography makes a valuable contribution to the understanding of anterior eye anatomy and supports the fitting process of contact lenses. Sagittal height data, determined by newer noninvasive techniques, are particularly useful for initial scleral lens selection. PURPOSE The purpose of this study was to investigate the agreement and repeatability of Fourier-based profilometry and Scheimpflug imaging, in the measurement of sagittal height and toricity of the corneoscleral region. METHODS Minimal (Minsag), maximal (Maxsag) sagittal height, toricity (Maxsag - Minsag), and the maximum possible measurement zone diameter of 38 subjects were compared using the Eye Surface Profiler (ESP; Eagle Eye, Houten, the Netherlands) and the corneoscleral profile module of the Pentacam (Oculus, Wetzlar, Germany) at two different sessions. Correlations between the instruments were analyzed using the Pearson coefficient. Differences between sessions and instruments were analyzed using Bland-Altman and paired t tests. RESULTS For an equal chord length, the measurement with Pentacam was significantly greater for Minsag (344 μm; 95% confidence interval [CI], 322 to 364 μm; P < .001) and significantly greater for Maxsag (280 μm; 95% CI, 256 to 305 μm; P < .001), but significantly smaller for toricity (-63 μm; 95% CI, -95 to -31 μm; P < .001). Maximum possible measurement zone diameter with ESP (16.4 ± 1.3 mm) was significantly greater than with Pentacam (14.8 ± 1.1 mm) (P < .001). Repeated measurements from session 1 and session 2 were not significantly different for Pentacam and ESP (P = .74 and P = .64, respectively). The 95% CIs around differences indicate good repeatability for Pentacam (mean difference, -0.9 μm; 95% CI, -6.7 to 4.8 μm) and ESP (4.6 μm; -22.4 to 31.6). CONCLUSIONS Although both instruments deliver useful data especially for the fitting of scleral and soft contact lenses, the sagittal height and the toricity measurements cannot be considered as interchangeable.
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Barnett M, Courey C, Fadel D, Lee K, Michaud L, Montani G, van der Worp E, Vincent SJ, Walker M, Bilkhu P, Morgan PB. CLEAR - Scleral lenses. Cont Lens Anterior Eye 2021; 44:270-288. [PMID: 33775380 DOI: 10.1016/j.clae.2021.02.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 02/01/2021] [Indexed: 12/25/2022]
Abstract
Scleral lenses were the first type of contact lens, developed in the late nineteenth century to restore vision and protect the ocular surface. With the advent of rigid corneal lenses in the middle of the twentieth century and soft lenses in the 1970's, the use of scleral lenses diminished; in recent times there has been a resurgence in their use driven by advances in manufacturing and ocular imaging technology. Scleral lenses are often the only viable form of contact lens wear across a range of clinical indications and can potentially delay the need for corneal surgery. This report provides a brief historical review of scleral lenses and a detailed account of contemporary scleral lens practice including common indications and recommended terminology. Recent research on ocular surface shape is presented, in addition to a comprehensive account of modern scleral lens fitting and on-eye evaluation. A range of optical and physiological challenges associated with scleral lenses are presented, including options for the clinical management of a range of ocular conditions. Future applications which take advantage of the stability of scleral lenses are also discussed. In summary, this report presents evidence-based recommendations to optimise patient outcomes in modern scleral lens practice.
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Affiliation(s)
- Melissa Barnett
- University of California, Davis Eye Center, Sacramento, CA, United States.
| | | | | | - Karen Lee
- University of Houston, College of Optometry, Houston, TX, United States
| | | | - Giancarlo Montani
- Università del Salento, Dipartimento di Matematica e Fisica CERCA, Lecce, Italy
| | - Eef van der Worp
- Eye-Contact-Lens Research & Education, Amsterdam, NL, Netherlands
| | - Stephen J Vincent
- Queensland University of Technology (QUT), Centre for Vision and Eye Research, School of Optometry and Vision Science, Contact Lens and Visual Optics Laboratory, Brisbane, Australia
| | - Maria Walker
- University of Houston, College of Optometry, Houston, TX, United States
| | - Paramdeep Bilkhu
- School of Optometry & Vision Science, Aston University, Birmingham, United Kingdom
| | - Philip B Morgan
- Eurolens Research, Division of Pharmacy and Optometry, University of Manchester, Manchester, United Kingdom
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Kowalski LP, Collins MJ, Vincent SJ. Scleral lens centration: The influence of centre thickness, scleral topography, and apical clearance. Cont Lens Anterior Eye 2020; 43:562-567. [DOI: 10.1016/j.clae.2019.11.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/06/2019] [Accepted: 11/27/2019] [Indexed: 12/19/2022]
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Bataille L, Molina-Martin A, Piñero DP. Intrasession repeatability of corneal, limbal and scleral measurements obtained with a fourier transform profilometer. Cont Lens Anterior Eye 2020; 44:101382. [PMID: 33243586 DOI: 10.1016/j.clae.2020.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 11/08/2020] [Accepted: 11/10/2020] [Indexed: 12/20/2022]
Abstract
PURPOSE To evaluate the intrasession repeatability of corneal, limbal and scleral measurements obtained by an experienced operator with a Fourier transform profilometer in healthy eyes. METHODS Prospective, single-center study including 35 eyes of 35 participants with ages ranging from 13 to 52 years. All patients underwent three consecutive corneoscleral topographic evaluations with the Eye Surface Profiler (ESP) system (Eaglet Eye b.v.). Intrasession repeatability was analyzed for different geometric and sagittal height variables using the following parameters: the within-subject standard deviation (Sw) of the three consecutive measurements, intrasubject precision (1.96 × Sw), coefficient of variation (CV) and the intraclass correlation coefficient (ICC). RESULTS Inner best fit sphere (BFS) showed good repeatability, with ICC of 0.844. Higher variability was observed for the repeated measurements of limbus and outer BFS, with ICCs of 0.636 and 0.739, respectively. For mean corneal and scleral radius, ICCs were 0.933 and 0.888, respectively. The repeatability of all sagittal height data was good for all chords evaluated (11-15 mm), with Sw values from 0.02 to 0.11 mm, and ICCs from 0.568 to 0.909. A significant positive correlation was found between the magnitude of temporal-nasal sagittal height difference for all measured chords and its Sw associated. CONCLUSION The ESP system can provide consistent measurements of sagittal height data for different chord diameters as well as for mean corneal and scleral radius in healthy eyes. Best fit approaches for limbal and scleral areas were less repeatable, although within a clinically acceptable range.
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Affiliation(s)
- Laurent Bataille
- Group of Optics and Visual Perception. Department of Optics, Pharmacology and Anatomy, University of Alicante, Spain
| | - Ainhoa Molina-Martin
- Group of Optics and Visual Perception. Department of Optics, Pharmacology and Anatomy, University of Alicante, Spain
| | - David P Piñero
- Group of Optics and Visual Perception. Department of Optics, Pharmacology and Anatomy, University of Alicante, Spain; Department of Ophthalmology, Vithas Medimar International Hospital, Alicante, Spain.
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Nau A, Shorter ES, Harthan JS, Fogt JS, Nau CB, Schornack M. Multicenter review of impression-based scleral devices. Cont Lens Anterior Eye 2020; 44:101380. [PMID: 33199216 DOI: 10.1016/j.clae.2020.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 10/18/2020] [Accepted: 10/28/2020] [Indexed: 12/30/2022]
Abstract
OBJECTIVE To describe outcomes using impression based-scleral devices for the management of anterior segment disease. METHODS Retrospective chart review identified all patients who were fitted with impression-based scleral devices between January 1, 2013 and June 30, 2019 at three specialty contact lens practices. Patient demographic data, indication for device use, visual and physiological outcomes, as well as details of the fitting process and survival of device use were determined. RESULTS Forty-four patients (70 eyes) were included in the study. Primary indications for device use included corneal irregularity (28 patients, 44 eyes) and ocular surface disease (16 patients, 26 eyes). Fifty-four percent of patients had more than one ocular surface condition, and 39 % of patients had undergone at least one anterior segment surgical procedure. Twenty-nine patients had unsuccessfully attempted to wear standard scleral lenses prior to being fit with impression-based devices. Visual acuity improved significantly with impression-based devices compared to habitual correction (p < 0.001). Completion of the fitting process (including visit to acquire the impression and post-fitting assessments) required an average of 4 [1.5] visits.Ideal haptic alignment was achieved with 74 % and complete limbal clearance was achieved in 83 % of fits. Device use was discontinued due to complications in two eyes. CONCLUSION Patients with complex eye disease who are unable to successfully wear standard scleral lenses successfully may achieve visual and therapeutic success with impression-based devices.
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Affiliation(s)
- Amy Nau
- Korb & Associates, Boston, MA, USA; New England College of Optometry, Boston, MA, USA.
| | | | | | - Jennifer S Fogt
- Ohio State University College of Optometry, Columbus, OH, USA
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Consejo A, Wu R, Abass A. Anterior Scleral Regional Variation between Asian and Caucasian Populations. J Clin Med 2020; 9:jcm9113419. [PMID: 33113864 PMCID: PMC7692638 DOI: 10.3390/jcm9113419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/13/2020] [Accepted: 10/21/2020] [Indexed: 02/06/2023] Open
Abstract
Purpose: To evaluate the anterior scleral shape regional differences between Asian and Caucasian populations. Methods: The study included 250 Asian eyes and 235 Caucasian eyes from participants aged 22 to 67 years (38.5 ± 7.6). Three-dimensional (3D) corneo-scleral maps were acquired using a corneo-scleral topographer (Eye Surface Profiler, Eaglet Eye BV) and used to calculate sagittal height. For each 3D map, the sclera (maximum diameter of 18 mm) and cornea were separated at the limbus using an automated technique. Advanced data processing steps were applied to ensure levelled artefact-free datasets to build an average scleral shape map for each population. Results: Statistically, Asian and Caucasian sclerae are significantly different from each other in sagittal height (overall sclera, p = 0.001). The largest difference in sagittal height between groups was found in the inferior-temporal region (271 ± 203 µm, p = 0.03), whereas the smallest difference was found in the superior-temporal region (84 ± 105 µm, p = 0.17). The difference in sagittal height between Caucasian and Asian sclera increases with the distance from the limbus. Conclusions: Asian anterior sclera was found to be less elevated than Caucasian anterior sclera. However, the nasal area of the sclera is less elevated than the temporal area, independently of race. Gaining knowledge in race-related scleral topography differences could assist contact lens manufacturers in the process of lens design and practitioners during the process of contact lens fitting.
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Affiliation(s)
- Alejandra Consejo
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Poland;
- Department of Applied Physics, University of Zaragoza, 50009 Zaragoza, Spain
| | - Richard Wu
- Department of Optometry, Central Taiwan University of Science and Technology, Taichung City 40601, Taiwan;
- College of Optometry, Pacific University, Forest Grove, OR 97116, USA
| | - Ahmed Abass
- School of Engineering, University of Liverpool, Liverpool L69 3GH, UK
- Correspondence:
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Moore J, Shu X, Lopes BT, Wu R, Abass A. Limbus misrepresentation in parametric eye models. PLoS One 2020; 15:e0236096. [PMID: 32970690 PMCID: PMC7514007 DOI: 10.1371/journal.pone.0236096] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 06/29/2020] [Indexed: 11/20/2022] Open
Abstract
Purpose To assess the axial, radial and tangential limbus position misrepresentation when parametric models are used to represent the cornea and the sclera. Methods This retrospective study included 135 subjects aged 22 to 65 years (36.5 mean ±9.8 STD), 71 females and 64 males. Topography measurements were taken using an Eye Surface Profiler topographer and processed by a custom-built MATLAB code. Eye surfaces were freed from edge-effect artefacts and fitted to spherical, conic and biconic models. Results When comparing the radial position of the limbus, average errors of -0.83±0.19mm, -0.76±0.20mm and -0.69±0.20mm were observed within the right eye population for the spherical, conic and biconic models fitted up to 5mm. For the same fitting radius, the average fitting errors were -0.86±0.23mm, -0.78±0.23mm and -0.73±0.23mm for the spherical, conic and biconic models respectively within the left eye population. For the whole cornea fit, the average errors were -0.27±0.12mm and -0.28±0.13mm for the spherical models, -0.02±0.29mm and -0.05±0.27mm for the conic models, and -0.22±0.16mm and 0.24±0.17mm for the biconic models in the right and left eye populations respectively. Conclusions Through the use of spherical, conic and biconic parametric modelling methods, the eye’s limbus is being mislocated. Additionally, it is evident that the magnitude of fitting error associated with the sclera may be propagating through the other components of the eye. This suggests that a corneal nonparametric model may be necessary to improve the representation of the limbus.
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Affiliation(s)
- Joshua Moore
- Department of Mathematical Sciences, University of Liverpool, Liverpool, United Kingdom
- School of Engineering, University of Liverpool, Liverpool, United Kingdom
| | - Xuhan Shu
- College of Physical Sciences, University of Guelph, Guelph, Canada
| | - Bernardo T. Lopes
- School of Engineering, University of Liverpool, Liverpool, United Kingdom
- Department of Ophthalmology, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Richard Wu
- Department of Optometry, Central Taiwan University of Science and Technology, Taichung, Taiwan
- College of Optometry, Pacific University, Forest Grove, Oregon, United States of America
| | - Ahmed Abass
- School of Engineering, University of Liverpool, Liverpool, United Kingdom
- * E-mail:
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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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Consejo A, Alonso-Caneiro D, Wojtkowski M, Vincent SJ. Corneal tissue properties following scleral lens wear using Scheimpflug imaging. Ophthalmic Physiol Opt 2020; 40:595-606. [PMID: 32705705 PMCID: PMC7540351 DOI: 10.1111/opo.12710] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 05/26/2020] [Indexed: 12/11/2022]
Abstract
Purpose To investigate the effect of short‐term scleral lens wear on the corneal stroma at a macroscopic (thickness) and microscopic (within tissue) level, including regional variations. Methods Fourteen young, healthy participants wore a rotationally symmetric, 16.5 mm diameter, scleral lens for 8 h. Scheimpflug images were captured before, and immediately after, lens wear, and also on a second day (without lens wear) to quantify natural corneal diurnal variations. After corneal segmentation, pixel intensities of the stromal tissue were statistically modelled using a Weibull probability density function from which parameters α and β were derived. Results Both α and β parameters increased significantly following scleral lens wear (by 5.7 ± 10% and 6.5 ± 6.5%, respectively, both p < 0.01). Corneal thickness also increased slightly following lens wear (mean increase 0.49 ± 1.77%, p = 0.01); however, the change in α and β parameters did not correlate with the magnitude of corneal swelling. On the control day, small but significant corneal thinning was observed (−0.82 ± 1.1%, p = 0.03), while α and β parameters remained stable. Both microparameters varied significantly across the cornea, with α decreasing (−15.4 ± 0.7%) and β increasing towards the periphery (+4.4 ± 2.6%) (both p < 0.001). Conclusion Corneal microparameters α and β varied regionally across the cornea and displayed a statistically significant increase following short‐term scleral lens wear, but remained stable between morning and evening measurements taken during a control day without lens wear. These corneal microparameters may be a useful metric to quantify subclinical corneal changes associated with low level hypoxia.
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Affiliation(s)
- Alejandra Consejo
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - David Alonso-Caneiro
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Australia
| | - Maciej Wojtkowski
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Stephen J Vincent
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Australia
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Walker MK, Schornack MM, Vincent SJ. Anatomical and physiological considerations in scleral lens wear: Conjunctiva and sclera. Cont Lens Anterior Eye 2020; 43:517-528. [PMID: 32624363 DOI: 10.1016/j.clae.2020.06.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 12/20/2022]
Abstract
While scleral lenses have been fitted using diagnostic lenses or impression moulding techniques for over a century, recent advances in anterior segment imaging such as optical coherence tomography and corneo-scleral profilometry have significantly improved the current understanding of the anatomy of the anterior eye including the morphometry of the conjunctiva, sclera, and corneo-scleral junction, as well as the ocular surface shape and elevation. These technological advances in ocular imaging along with continual improvements and innovations in scleral lens design and manufacturing have led to a global increase in scleral lens prescribing. This review provides a comprehensive overview of the conjunctiva and sclera in the context of modern scleral lens practice, including anatomical variations in healthy and diseased eyes, the physiological impact of scleral lens wear, potential fitting challenges, and current approaches to lens modifications in order to minimise lens-induced complications and adverse ocular effects. Specific topics requiring further research are also discussed.
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Affiliation(s)
- Maria K Walker
- University of Houston College of Optometry, The Ocular Surface Institute, Houston, USA
| | | | - Stephen J Vincent
- Queensland University of Technology (QUT), Centre for Vision and Eye Research, School of Optometry and Vision Science, Contact Lens and Visual Optics Laboratory, Institute of Health and Biomedical Innovation, Queensland, Australia.
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Cheung SY, Collins MJ, Vincent SJ. The impact of short-term fenestrated scleral lens wear on intraocular pressure. Cont Lens Anterior Eye 2020; 43:585-588. [PMID: 32088133 DOI: 10.1016/j.clae.2020.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 02/06/2020] [Accepted: 02/13/2020] [Indexed: 12/18/2022]
Abstract
PURPOSE To examine the influence of short-term fenestrated scleral lens wear on intraocular pressure (IOP) in healthy eyes. METHODS IOP was measured before, during, and after a brief period (1-2 min) of fenestrated, scleral lens wear, using a rebound tonometer, in fifty, young healthy adults (mean age 23 ± 4 years) with normal corneas. RESULTS Immediately following lens insertion, 48 of the 50 (96 %) of participants displayed an increase in IOP (mean ± SD increase in these participants of 3.8 ± 2.0 mmHg). Immediately following lens removal, 50 % of participants displayed a reduction in IOP, equal to or lower than, the pre-insertion IOP (-1.0 ± 0.8 mmHg lower than baseline). The remaining 50 % of participants displayed an IOP slightly greater than the pre-insertion IOP (1.6 ± 1.0 mmHg greater) after lens removal. CONCLUSIONS Short-term fenestrated scleral lens wear resulted in a small, but statistically significant, increase in IOP in 96 % of young healthy participants (< 4 mmHg on average), which decreased to a level similar to pre-lens insertion IOP levels immediately following lens removal. Further research is required to determine if this measured change in IOP during scleral lens wear is artefactual, or an elevation in the true IOP.
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Affiliation(s)
- Samuel Y Cheung
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Australia
| | - Michael J Collins
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Australia
| | - Stephen J Vincent
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Australia.
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Consejo A, Rozema JJ. In vivo anterior scleral morphometry, axial length and myopia. Cont Lens Anterior Eye 2020; 43:21-25. [DOI: 10.1016/j.clae.2018.10.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 10/26/2018] [Accepted: 10/26/2018] [Indexed: 12/01/2022]
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Vincent SJ, Fadel D. Optical considerations for scleral contact lenses: A review. Cont Lens Anterior Eye 2019; 42:598-613. [DOI: 10.1016/j.clae.2019.04.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/24/2019] [Accepted: 04/25/2019] [Indexed: 01/07/2023]
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Abass A, Lopes BT, Eliasy A, Salomao M, Wu R, White L, Jones S, Clamp J, Ambrósio R, Elsheikh A. Artefact-free topography based scleral-asymmetry. PLoS One 2019; 14:e0219789. [PMID: 31348792 PMCID: PMC6660081 DOI: 10.1371/journal.pone.0219789] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 07/01/2019] [Indexed: 12/18/2022] Open
Abstract
PURPOSE To present a three-dimensional non-parametric method for detecting scleral asymmetry using corneoscleral topography data that are free of edge-effect artefacts. METHODS The study included 88 participants aged 23 to 65 years (37.7±9.7), 47 women and 41 men. The eye topography data were exported from the Eye Surface Profiler software in MATLAB binary data container format then processed by custom built MATLAB codes entirely independent from the profiler software. Scleral asymmetry was determined initially from the unprocessed topography before being determined again after removing the edge-effect noise. Topography data were levelled around the limbus, then edge-effect was eliminated using a robust statistical moving median technique. In addition to comparing raw elevation data, scleral elevation was also compared through fitting a sphere to every single scleral surface and determining the relative elevation from the best-fit sphere reference surface. RESULTS When considering the averaged raw topography elevation data in the scleral section of the eye at radius 8 mm, the average raw elevations of the right eyes' sclera were -1.5±1.77, -1.87±2.12, -1.36±1.82 and -1.57±1.87 mm. In the left eyes at the same radius the average raw elevations were -1.62±1.78, -1.82±2.07, -1.28±1.76 and -1.68±1.93 mm. While, when considering the average raw elevation of the sclera after removing the edge effect, the average raw elevations of the right eyes were -3.71±0.25, -4.06±0.23, -3.95±0.19 and -3.95±0.23 mm. In the left eyes at the same radius the average raw elevations were -3.71±0.19, -3.97±0.22, -3.96±0.19 and -3.96±0.18 mm in the nasal, temporal, superior and inferior sides respectively. Maximum raw elevation asymmetry in the averaged scleral raw elevation was 1.6647±0.9015 mm in right eyes and 1.0358±0.6842 mm in left eyes, both detected at -38° to the nasal side. Best-fit sphere-based relative elevation showed that sclera is more elevated in three main meridians at angles -40°, 76°, and 170° in right eyes and -40°, 76°, and 170° in left eyes, all measured from the nasal meridian. Maximum recorded relative elevation asymmetries were 0.0844±0.0355 mm and 0.068±0.0607 mm at angular positions 76° and 63.5° for right and left eyes in turn. CONCLUSIONS It is not possible to use corneoscleral topography data to predict the scleral shape without considering a method of removing the edge-effect from the topography data. The nasal side of the sclera is higher than the temporal side, therefore, rotationally symmetric scleral contact lenses are more likely to be translated towards the temporal side. The scleral shape is best described by levelled raw elevation rather than relative elevation.
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Affiliation(s)
- Ahmed Abass
- School of Engineering, University of Liverpool, Liverpool, United Kingdom
- * E-mail:
| | - 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
| | - Lynn White
- UltraVision CLPL, Leighton Buzzard, United Kingdom
| | - Steve Jones
- School of Engineering, University of Liverpool, Liverpool, United Kingdom
| | - John Clamp
- UltraVision CLPL, Leighton Buzzard, United Kingdom
| | - Renato Ambrósio
- Federal University of São Paulo, São Paulo, Brazil
- Federal University of the State of Rio de Janeiro, RJ, Brazil
| | - 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
- School of Biological Science and Biomedical Engineering, Beihang University, Beijing, China
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