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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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Fu L, Jiang Y, Lian H, Lou J, Chen R, Li Z, Zhang Y. The corneal biomechanical differences after wearing orthokeratology lenses and multifocal soft lenses in children: A self-control study. Cont Lens Anterior Eye 2024; 47:102089. [PMID: 37951739 DOI: 10.1016/j.clae.2023.102089] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 10/18/2023] [Accepted: 11/03/2023] [Indexed: 11/14/2023]
Abstract
BACKGROUND To compare the changes in corneal biomechanics after orthokeratology (OK) lens and Defocus Incorporated Soft Contact (DISC) lens treatment. METHODS Of 28 myopic children were recruited, with one eye wearing OK lens and the other eye wearing DISC lens for one year, and the data after discontinued for 4 weeks were also collected. Major outcomes were corneal biomechanics and axial length (AL) elongation. RESULTS Throughout the follow-up period, the DISC group had longer the first applanation (A1) time, larger A1 deformation amplitude, A1 deflection length (A1 DLL), and A1 deflection amplitude than the OK group. AL elongation was less in the OK group at each visit (all P < 0.05) but faster in the OK group than in the DISC group after discontinuation (P = 0.006). Moreover, AL elongation was related to baseline A1 time, A1 velocity and whole eye movement max in the DISC group, and in the OK group, was related to the baseline the second applanation (A2) DLL, A2 delta arc length and stiffness parameter A1 (all P < 0.05). CONCLUSIONS The cornea was more deformable after wearing DISC lens than OK lens, and corneal biomechanical parameters were associated with AL elongation. Eyes showed less AL elongation during OK lens treatment while faster AL elongation after discontinuation than DISC lens. The baseline corneal biomechanics may help to predict AL elongation in myopic control strategies.
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Affiliation(s)
- Lin Fu
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China.
| | - Yi Jiang
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China.
| | - Hengli Lian
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China.
| | - Jiangtao Lou
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China.
| | - Ruru Chen
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China.
| | - Zhangliang Li
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China.
| | - Yunjie Zhang
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China.
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Zhang P, Wu J, Jiang J, Zhang X, Ran Z, Jiang F, Zheng X, Wang J, Elsheikh A, Bao F. Evaluation of changes in corneal biomechanics after orthokeratology using Corvis ST. Cont Lens Anterior Eye 2024; 47:102100. [PMID: 38072740 DOI: 10.1016/j.clae.2023.102100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 11/25/2023] [Accepted: 11/27/2023] [Indexed: 01/22/2024]
Abstract
PURPOSE To investigate the alterations in corneal biomechanical metrics induced by orthokeratology (ortho-k) using Corvis ST and to determine the factors influencing these changes. METHOD A prospective observational study was conducted to analyze various Corvis ST parameters in 32 children with low to moderate myopia who successfully underwent ortho-k lens fitting. Corneal biomechanical measurements via Corvis ST were acquired at six distinct time points: baseline (pre) and 2 h (pos2h), 6 h (pos6h), and 10 h (pos10h) following the removal of the first overnight wear ortho-k, one week (pos1w) and one month (pos1m) subsequent to the initiation of ortho-k. RESULT Significant differences were observed in Corvis ST Biomechanical parameters DAR2, IIR, CBI, and cCBI post ortho-k intervention. The integration of covariates (CCT, SimK, and bIOP) mitigated the differences in DAR2, IIR, and cCBI, but not in CBI. Initially, the stiffness parameter at first applanation, SP-A1, did not demonstrate significant variations, but after adjusting for covariates, noticeable differences over time were observed. The Stress-Strain Indeces, SSIv1 and SSIv2, did not manifest considerable changes over time, irrespective of the adjustment for covariates. No significant disparities were identified among different ortho-k lens brands. CONCLUSION Corneal biomechanics remained consistent throughout the one-month period of ortho-k lens wear. The observed changes in Corvis ST parameters subsequent ortho-k are primarily attributable to alterations in corneal pachymetry and morphology, rather than actual alterations in corneal biomechanics. The stability of corneal biomechanics post ortho-k treatment suggests the safety of this approach for adolescents from a corneal biomechanics perspective.
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Affiliation(s)
- PeiPei Zhang
- National Clinical Research Center for Ocular Diseases, Eye Hospital, WenZhou Medical University, Wenzhou 325027, China
| | - JinFang Wu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China.
| | - Jun Jiang
- National Clinical Research Center for Ocular Diseases, Eye Hospital, WenZhou Medical University, Wenzhou 325027, China
| | - XinYu Zhang
- National Clinical Research Center for Ocular Diseases, Eye Hospital, WenZhou Medical University, Wenzhou 325027, China
| | - ZiYing Ran
- School of Engineering, University of Liverpool, Liverpool L69 3GH, UK
| | - Fan Jiang
- National Clinical Research Center for Ocular Diseases, Eye Hospital, WenZhou Medical University, Wenzhou 325027, China.
| | - XiaoBo Zheng
- National Clinical Research Center for Ocular Diseases, Eye Hospital, WenZhou Medical University, Wenzhou 325027, China; National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; The Institute of Ocular Biomechanics, Wenzhou Medical University, Wenzhou 325027, China
| | - JunJie Wang
- National Clinical Research Center for Ocular Diseases, Eye Hospital, WenZhou Medical University, Wenzhou 325027, China; National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; The Institute of Ocular Biomechanics, Wenzhou Medical University, Wenzhou 325027, China
| | - Ahmed Elsheikh
- School of Engineering, University of Liverpool, Liverpool L69 3GH, UK; National Institute for Health Research (NIHR) Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK; Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100083, China
| | - FangJun Bao
- National Clinical Research Center for Ocular Diseases, Eye Hospital, WenZhou Medical University, Wenzhou 325027, China; National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; The Institute of Ocular Biomechanics, Wenzhou Medical University, Wenzhou 325027, China.
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Ruan J, Zhang Y, Chen Y. Influence of overnight orthokeratology on tear film and meibomian glands in myopic children: a prospective study. BMC Ophthalmol 2023; 23:136. [PMID: 37013481 PMCID: PMC10071684 DOI: 10.1186/s12886-023-02883-8] [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: 12/16/2022] [Accepted: 03/24/2023] [Indexed: 04/05/2023] Open
Abstract
BACKGROUND Orthokeratology lenses, which are worn overnight, are recommended for reducing myopia progression. They lie on the cornea and can influence the ocular surface by temporarily reshaping the corneal surface through a reverse geometry design. This study investigated the effect of overnight orthokeratology lenses on tear film stability and meibomian gland status in children aged 8-15 years. METHODS This prospective, self-controlled study included 33 children with monocular myopia who were prescribed orthokeratology lenses for at least one year. The experimental group (ortho-k group) comprised 33 myopic eyes. The control group comprised the emmetropic eyes of the same participants. Tear film stability and meibomian gland status were measured using a Keratograph 5M (Oculus, Wetzlar, Germany). Paired t-tests and Wilcoxon signed-rank tests were used to compare the data between the two groups. RESULTS At the one-year visit, the non-invasive first tear film break-up time (NIBUTf) values were 6.15 ± 2.56 s and 6.18 ± 2.61 s in the experimental and control groups, respectively. The lower tear meniscus height was 18.74 ± 0.05 μm and 18.65 ± 0.04 μm in these groups, respectively. No significant difference was observed in loss of meibomian glands or non-invasive average tear film break-up time between the experimental and control groups using Wilcoxon signed-rank tests. CONCLUSIONS The stability of the tear film and meibomian gland status were not significantly affected by wearing orthokeratology lenses overnight, indicating that continuous use of orthokeratology lenses for 12 months has a minimal effect on the ocular surface. This finding can help guide the clinical management of tear film quality with respect to the use of orthokeratology contact lenses.
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Affiliation(s)
- Jing Ruan
- Department of Ophthalmology, Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, 49 North Huayuan Road, Haidian District, Beijing, 100191, China
| | - Yu Zhang
- Department of Ophthalmology, Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, 49 North Huayuan Road, Haidian District, Beijing, 100191, China.
| | - Yueguo Chen
- Department of Ophthalmology, Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Peking University Third Hospital, 49 North Huayuan Road, Haidian District, Beijing, 100191, China.
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Lawrenson JG, Shah R, Huntjens B, Downie LE, Virgili G, Dhakal R, Verkicharla PK, Li D, Mavi S, Kernohan A, Li T, Walline JJ. Interventions for myopia control in children: a living systematic review and network meta-analysis. Cochrane Database Syst Rev 2023; 2:CD014758. [PMID: 36809645 PMCID: PMC9933422 DOI: 10.1002/14651858.cd014758.pub2] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
BACKGROUND Myopia is a common refractive error, where elongation of the eyeball causes distant objects to appear blurred. The increasing prevalence of myopia is a growing global public health problem, in terms of rates of uncorrected refractive error and significantly, an increased risk of visual impairment due to myopia-related ocular morbidity. Since myopia is usually detected in children before 10 years of age and can progress rapidly, interventions to slow its progression need to be delivered in childhood. OBJECTIVES To assess the comparative efficacy of optical, pharmacological and environmental interventions for slowing myopia progression in children using network meta-analysis (NMA). To generate a relative ranking of myopia control interventions according to their efficacy. To produce a brief economic commentary, summarising the economic evaluations assessing myopia control interventions in children. To maintain the currency of the evidence using a living systematic review approach. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register), MEDLINE; Embase; and three trials registers. The search date was 26 February 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) of optical, pharmacological and environmental interventions for slowing myopia progression in children aged 18 years or younger. Critical outcomes were progression of myopia (defined as the difference in the change in spherical equivalent refraction (SER, dioptres (D)) and axial length (mm) in the intervention and control groups at one year or longer) and difference in the change in SER and axial length following cessation of treatment ('rebound'). DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methods. We assessed bias using RoB 2 for parallel RCTs. We rated the certainty of evidence using the GRADE approach for the outcomes: change in SER and axial length at one and two years. Most comparisons were with inactive controls. MAIN RESULTS We included 64 studies that randomised 11,617 children, aged 4 to 18 years. Studies were mostly conducted in China or other Asian countries (39 studies, 60.9%) and North America (13 studies, 20.3%). Fifty-seven studies (89%) compared myopia control interventions (multifocal spectacles, peripheral plus spectacles (PPSL), undercorrected single vision spectacles (SVLs), multifocal soft contact lenses (MFSCL), orthokeratology, rigid gas-permeable contact lenses (RGP); or pharmacological interventions (including high- (HDA), moderate- (MDA) and low-dose (LDA) atropine, pirenzipine or 7-methylxanthine) against an inactive control. Study duration was 12 to 36 months. The overall certainty of the evidence ranged from very low to moderate. Since the networks in the NMA were poorly connected, most estimates versus control were as, or more, imprecise than the corresponding direct estimates. Consequently, we mostly report estimates based on direct (pairwise) comparisons below. At one year, in 38 studies (6525 participants analysed), the median change in SER for controls was -0.65 D. The following interventions may reduce SER progression compared to controls: HDA (mean difference (MD) 0.90 D, 95% confidence interval (CI) 0.62 to 1.18), MDA (MD 0.65 D, 95% CI 0.27 to 1.03), LDA (MD 0.38 D, 95% CI 0.10 to 0.66), pirenzipine (MD 0.32 D, 95% CI 0.15 to 0.49), MFSCL (MD 0.26 D, 95% CI 0.17 to 0.35), PPSLs (MD 0.51 D, 95% CI 0.19 to 0.82), and multifocal spectacles (MD 0.14 D, 95% CI 0.08 to 0.21). By contrast, there was little or no evidence that RGP (MD 0.02 D, 95% CI -0.05 to 0.10), 7-methylxanthine (MD 0.07 D, 95% CI -0.09 to 0.24) or undercorrected SVLs (MD -0.15 D, 95% CI -0.29 to 0.00) reduce progression. At two years, in 26 studies (4949 participants), the median change in SER for controls was -1.02 D. The following interventions may reduce SER progression compared to controls: HDA (MD 1.26 D, 95% CI 1.17 to 1.36), MDA (MD 0.45 D, 95% CI 0.08 to 0.83), LDA (MD 0.24 D, 95% CI 0.17 to 0.31), pirenzipine (MD 0.41 D, 95% CI 0.13 to 0.69), MFSCL (MD 0.30 D, 95% CI 0.19 to 0.41), and multifocal spectacles (MD 0.19 D, 95% CI 0.08 to 0.30). PPSLs (MD 0.34 D, 95% CI -0.08 to 0.76) may also reduce progression, but the results were inconsistent. For RGP, one study found a benefit and another found no difference with control. We found no difference in SER change for undercorrected SVLs (MD 0.02 D, 95% CI -0.05 to 0.09). At one year, in 36 studies (6263 participants), the median change in axial length for controls was 0.31 mm. The following interventions may reduce axial elongation compared to controls: HDA (MD -0.33 mm, 95% CI -0.35 to 0.30), MDA (MD -0.28 mm, 95% CI -0.38 to -0.17), LDA (MD -0.13 mm, 95% CI -0.21 to -0.05), orthokeratology (MD -0.19 mm, 95% CI -0.23 to -0.15), MFSCL (MD -0.11 mm, 95% CI -0.13 to -0.09), pirenzipine (MD -0.10 mm, 95% CI -0.18 to -0.02), PPSLs (MD -0.13 mm, 95% CI -0.24 to -0.03), and multifocal spectacles (MD -0.06 mm, 95% CI -0.09 to -0.04). We found little or no evidence that RGP (MD 0.02 mm, 95% CI -0.05 to 0.10), 7-methylxanthine (MD 0.03 mm, 95% CI -0.10 to 0.03) or undercorrected SVLs (MD 0.05 mm, 95% CI -0.01 to 0.11) reduce axial length. At two years, in 21 studies (4169 participants), the median change in axial length for controls was 0.56 mm. The following interventions may reduce axial elongation compared to controls: HDA (MD -0.47mm, 95% CI -0.61 to -0.34), MDA (MD -0.33 mm, 95% CI -0.46 to -0.20), orthokeratology (MD -0.28 mm, (95% CI -0.38 to -0.19), LDA (MD -0.16 mm, 95% CI -0.20 to -0.12), MFSCL (MD -0.15 mm, 95% CI -0.19 to -0.12), and multifocal spectacles (MD -0.07 mm, 95% CI -0.12 to -0.03). PPSL may reduce progression (MD -0.20 mm, 95% CI -0.45 to 0.05) but results were inconsistent. We found little or no evidence that undercorrected SVLs (MD -0.01 mm, 95% CI -0.06 to 0.03) or RGP (MD 0.03 mm, 95% CI -0.05 to 0.12) reduce axial length. There was inconclusive evidence on whether treatment cessation increases myopia progression. Adverse events and treatment adherence were not consistently reported, and only one study reported quality of life. No studies reported environmental interventions reporting progression in children with myopia, and no economic evaluations assessed interventions for myopia control in children. AUTHORS' CONCLUSIONS Studies mostly compared pharmacological and optical treatments to slow the progression of myopia with an inactive comparator. Effects at one year provided evidence that these interventions may slow refractive change and reduce axial elongation, although results were often heterogeneous. A smaller body of evidence is available at two or three years, and uncertainty remains about the sustained effect of these interventions. Longer-term and better-quality studies comparing myopia control interventions used alone or in combination are needed, and improved methods for monitoring and reporting adverse effects.
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Affiliation(s)
- John G Lawrenson
- Centre for Applied Vision Research, School of Health & Psychological Sciences , City, University of London, London, UK
| | - Rakhee Shah
- Centre for Applied Vision Research, School of Health & Psychological Sciences , City, University of London, London, UK
| | - Byki Huntjens
- Centre for Applied Vision Research, School of Health & Psychological Sciences , City, University of London, London, UK
| | - Laura E Downie
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Australia
| | - Gianni Virgili
- Department of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Florence, Italy
- Centre for Public Health, Queen's University Belfast, Belfast, UK
| | - Rohit Dhakal
- Myopia Research Lab, Prof. Brien Holden Eye Research Centre, L V Prasad Eye Institute, Hyderabad, India
| | - Pavan K Verkicharla
- Myopia Research Lab, Prof. Brien Holden Eye Research Centre, L V Prasad Eye Institute, Hyderabad, India
| | - Dongfeng Li
- Centre for Public Health, Queen's University Belfast, Belfast, UK
- Department of Ophthalmology, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Sonia Mavi
- Centre for Public Health, Queen's University Belfast, Belfast, UK
| | - Ashleigh Kernohan
- Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Tianjing Li
- Department of Ophthalmology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, USA
| | - Jeffrey J Walline
- College of Optometry, The Ohio State University, Columbus, Ohio, USA
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Lu W, Ding W, Ji R, Tian Y, Zhao C, Li H, Jiao M, Guo Z, Leng L. Repeatability and correlation of corneal biomechanical measurements obtained by Corvis ST in orthokeratology patients. Cont Lens Anterior Eye 2022; 46:101793. [PMID: 36509642 DOI: 10.1016/j.clae.2022.101793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 12/02/2022] [Accepted: 12/04/2022] [Indexed: 12/14/2022]
Abstract
PURPOSE To evaluate the repeatability of the corneal biomechanical measurements obtained by Corvis ST in post-orthokeratology patients and analyze the correlation between the biomechanical and ocular parameters. METHODS Fifty-one eyes of 51 myopic subjects were included in this study. The biomechanical parameters were assessed using Corvis ST. Repeatability was assessed using one-way ANOVA based on within-subject standard deviation (Sw), repeatability coefficient (RC), intraclass correlation coefficient (ICC) and correlation of variation (CoV). The correlation was evaluated using Pearson correlation analysis. RESULTS All parameters measured by Corvis ST, except length of flattened cornea at the first and second applanations (A1L and A2L), showed a good intraobserver repeatability after a 3-month follow-up period. The ICC values for A1L and A2L were 0.444 and 0.654, whereas the other parameters were higher than 0.8. Similar trends were obtained for CoV, wherein the CoV values for A1L and A2L were greater than 13 %. The corneal biomechanical parameters were correlated with age, refraction, axial length (AL), steep and flat keratometry before and after orthokeratology, and central corneal thickness (CCT). Following orthokeratology treatment, post-keratometry demonstrated a higher correlation with stiffness parameter at first applanation (SP-A1), velocity of corneal apex at the first applanation (A1V), and radius than pre-keratometry, which showed a weak correlation with SP-A1. CONCLUSION Corneal biomechanical parameters assessed using Corvis ST demonstrated a good repeatability, except A1L and A2L. The corneal biomechanical parameters were correlated with age, refraction, AL and pre- and post-keratometry. Thus, Corvis ST is a suitable device for investigating biomechanical parameter.
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Affiliation(s)
- Weicong Lu
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Wenzhi Ding
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Rongyuan Ji
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Yuyin Tian
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Chenpei Zhao
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Honglei Li
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Mengjun Jiao
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Zhen Guo
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China
| | - Lin Leng
- Eye Institute of Shandong First Medical University, Qingdao Eye Hospital of Shandong First Medical University, Shandong, China; State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong, China; School of Ophthalmology, Shandong First Medical University, Shandong, China.
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Xu Y, Ye Y, Chen Z, Xu J, Yang Y, Fan Y, Liu P, Chong IT, Yu K, Lam DC, Yu M. Corneal Stiffness and Modulus of Normal-Tension Glaucoma in Chinese. Am J Ophthalmol 2022; 242:131-138. [DOI: 10.1016/j.ajo.2022.06.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 06/19/2022] [Accepted: 06/20/2022] [Indexed: 11/01/2022]
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Wang Y, Cao H. Corneal and Scleral Biomechanics in Ophthalmic Diseases: An Updated Review. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2022. [DOI: 10.1016/j.medntd.2022.100140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Xu Y, Ye Y, Chong IT, Chen Z, Xu J, Yang Y, Yu K, Lam DCC, Yu M. A Novel Indentation Assessment to Measure Corneal Biomechanical Properties in Glaucoma and Ocular Hypertension. Transl Vis Sci Technol 2021; 10:36. [PMID: 34459861 PMCID: PMC8411863 DOI: 10.1167/tvst.10.9.36] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Purpose To evaluate the ability of the new in vivo corneal indentation device (CID) to measure corneal biomechanical properties. Methods and Results In total, 186 eyes from 46 healthy subjects, 107 patients with primary open-angle glaucoma, and 33 patients with ocular hypertension were enrolled in a cross-sectional study. Measurements were performed using corneal visualization Scheimpflug technology (Corvis ST) and the CID. The deformation amplitude (DA), inward applanation time, inward applanation velocity (A1V), outward applanation time (A2T), outward applanation velocity (A2V), highest concavity time, DA ratio, max inverse radius (MIR), integrated radius, and stiffness parameter A1 were included as Corvis ST parameters, and stiffness and modulus were included as CID parameters. Associations between the Corvis ST and CID parameters and correlations between central corneal thickness and corneal biomechanical parameters were analyzed. The stiffness was significantly correlated with all the Corvis ST parameters (P < 0.05). The modulus was significantly correlated with the DA, A1V, A2T, A2V, highest concavity time, and MIR (P < 0.05). The DA, inward applanation time, A1V, A2T, A2V, DA ratio, MIR, integrated radius, and stiffness parameter A1 values and both CID-derived values were significantly correlated with central corneal thickness (P < 0.05). Conclusions Parameters derived from the CID and Corvis ST demonstrated agreement in the measurement of corneal biomechanical properties. The stiffness and modulus can characterize in vivo corneal biomechanical properties. Translational Relevance Agreeing with the Corvis ST regarding the assessment of corneal biomechanical properties, the CID can be a novel clinical tool for biomechanical evaluation of the cornea.
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Affiliation(s)
- Yunzhi Xu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yiming Ye
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Iok Tong Chong
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Zidong Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Jiangang Xu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Yangfan Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Keming Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - David C C Lam
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Minbin Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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Vincent SJ, Cho P, Chan KY, Fadel D, Ghorbani-Mojarrad N, González-Méijome JM, Johnson L, Kang P, Michaud L, Simard P, Jones L. CLEAR - Orthokeratology. Cont Lens Anterior Eye 2021; 44:240-269. [DOI: 10.1016/j.clae.2021.02.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 02/01/2021] [Indexed: 12/25/2022]
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11
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Wan K, Lau JKK, Cheung SW, Cho P. Refractive and corneal responses of young myopic children to short-term orthokeratology treatment with different compression factors. Cont Lens Anterior Eye 2020; 43:65-72. [DOI: 10.1016/j.clae.2019.10.134] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 09/09/2019] [Accepted: 10/20/2019] [Indexed: 02/06/2023]
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Walline JJ, Lindsley KB, Vedula SS, Cotter SA, Mutti DO, Ng SM, Twelker JD. Interventions to slow progression of myopia in children. Cochrane Database Syst Rev 2020; 1:CD004916. [PMID: 31930781 PMCID: PMC6984636 DOI: 10.1002/14651858.cd004916.pub4] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Nearsightedness (myopia) causes blurry vision when one is looking at distant objects. Interventions to slow the progression of myopia in children include multifocal spectacles, contact lenses, and pharmaceutical agents. OBJECTIVES To assess the effects of interventions, including spectacles, contact lenses, and pharmaceutical agents in slowing myopia progression in children. SEARCH METHODS We searched CENTRAL; Ovid MEDLINE; Embase.com; PubMed; the LILACS Database; and two trial registrations up to February 2018. A top up search was done in February 2019. SELECTION CRITERIA We included randomized controlled trials (RCTs). We excluded studies when most participants were older than 18 years at baseline. We also excluded studies when participants had less than -0.25 diopters (D) spherical equivalent myopia. DATA COLLECTION AND ANALYSIS We followed standard Cochrane methods. MAIN RESULTS We included 41 studies (6772 participants). Twenty-one studies contributed data to at least one meta-analysis. Interventions included spectacles, contact lenses, pharmaceutical agents, and combination treatments. Most studies were conducted in Asia or in the United States. Except one, all studies included children 18 years or younger. Many studies were at high risk of performance and attrition bias. Spectacle lenses: undercorrection of myopia increased myopia progression slightly in two studies; children whose vision was undercorrected progressed on average -0.15 D (95% confidence interval [CI] -0.29 to 0.00; n = 142; low-certainty evidence) more than those wearing fully corrected single vision lenses (SVLs). In one study, axial length increased 0.05 mm (95% CI -0.01 to 0.11) more in the undercorrected group than in the fully corrected group (n = 94; low-certainty evidence). Multifocal lenses (bifocal spectacles or progressive addition lenses) yielded small effect in slowing myopia progression; children wearing multifocal lenses progressed on average 0.14 D (95% CI 0.08 to 0.21; n = 1463; moderate-certainty evidence) less than children wearing SVLs. In four studies, axial elongation was less for multifocal lens wearers than for SVL wearers (-0.06 mm, 95% CI -0.09 to -0.04; n = 896; moderate-certainty evidence). Three studies evaluating different peripheral plus spectacle lenses versus SVLs reported inconsistent results for refractive error and axial length outcomes (n = 597; low-certainty evidence). Contact lenses: there may be little or no difference between vision of children wearing bifocal soft contact lenses (SCLs) and children wearing single vision SCLs (mean difference (MD) 0.20D, 95% CI -0.06 to 0.47; n = 300; low-certainty evidence). Axial elongation was less for bifocal SCL wearers than for single vision SCL wearers (MD -0.11 mm, 95% CI -0.14 to -0.08; n = 300; low-certainty evidence). Two studies investigating rigid gas permeable contact lenses (RGPCLs) showed inconsistent results in myopia progression; these two studies also found no evidence of difference in axial elongation (MD 0.02mm, 95% CI -0.05 to 0.10; n = 415; very low-certainty evidence). Orthokeratology contact lenses were more effective than SVLs in slowing axial elongation (MD -0.28 mm, 95% CI -0.38 to -0.19; n = 106; moderate-certainty evidence). Two studies comparing spherical aberration SCLs with single vision SCLs reported no difference in myopia progression nor in axial length (n = 209; low-certainty evidence). Pharmaceutical agents: at one year, children receiving atropine eye drops (3 studies; n = 629), pirenzepine gel (2 studies; n = 326), or cyclopentolate eye drops (1 study; n = 64) showed significantly less myopic progression compared with children receiving placebo: MD 1.00 D (95% CI 0.93 to 1.07), 0.31 D (95% CI 0.17 to 0.44), and 0.34 (95% CI 0.08 to 0.60), respectively (moderate-certainty evidence). Axial elongation was less for children treated with atropine (MD -0.35 mm, 95% CI -0.38 to -0.31; n = 502) and pirenzepine (MD -0.13 mm, 95% CI -0.14 to -0.12; n = 326) than for those treated with placebo (moderate-certainty evidence) in two studies. Another study showed favorable results for three different doses of atropine eye drops compared with tropicamide eye drops (MD 0.78 D, 95% CI 0.49 to 1.07 for 0.1% atropine; MD 0.81 D, 95% CI 0.57 to 1.05 for 0.25% atropine; and MD 1.01 D, 95% CI 0.74 to 1.28 for 0.5% atropine; n = 196; low-certainty evidence) but did not report axial length. Systemic 7-methylxanthine had little to no effect on myopic progression (MD 0.07 D, 95% CI -0.09 to 0.24) nor on axial elongation (MD -0.03 mm, 95% CI -0.10 to 0.03) compared with placebo in one study (n = 77; moderate-certainty evidence). One study did not find slowed myopia progression when comparing timolol eye drops with no drops (MD -0.05 D, 95% CI -0.21 to 0.11; n = 95; low-certainty evidence). Combinations of interventions: two studies found that children treated with atropine plus multifocal spectacles progressed 0.78 D (95% CI 0.54 to 1.02) less than children treated with placebo plus SVLs (n = 191; moderate-certainty evidence). One study reported -0.37 mm (95% CI -0.47 to -0.27) axial elongation for atropine and multifocal spectacles when compared with placebo plus SVLs (n = 127; moderate-certainty evidence). Compared with children treated with cyclopentolate plus SVLs, those treated with atropine plus multifocal spectacles progressed 0.36 D less (95% CI 0.11 to 0.61; n = 64; moderate-certainty evidence). Bifocal spectacles showed small or negligible effect compared with SVLs plus timolol drops in one study (MD 0.19 D, 95% CI 0.06 to 0.32; n = 97; moderate-certainty evidence). One study comparing tropicamide plus bifocal spectacles versus SVLs reported no statistically significant differences between groups without quantitative results. No serious adverse events were reported across all interventions. Participants receiving antimuscarinic topical medications were more likely to experience accommodation difficulties (Risk Ratio [RR] 9.05, 95% CI 4.09 to 20.01) and papillae and follicles (RR 3.22, 95% CI 2.11 to 4.90) than participants receiving placebo (n=387; moderate-certainty evidence). AUTHORS' CONCLUSIONS Antimuscarinic topical medication is effective in slowing myopia progression in children. Multifocal lenses, either spectacles or contact lenses, may also confer a small benefit. Orthokeratology contact lenses, although not intended to modify refractive error, were more effective than SVLs in slowing axial elongation. We found only low or very low-certainty evidence to support RGPCLs and sperical aberration SCLs.
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Affiliation(s)
- Jeffrey J Walline
- The Ohio State University, College of Optometry, 338 West Tenth Avenue, Columbus, Ohio, USA, 43210-1240
| | - Kristina B Lindsley
- IBM Watson Health, Life Sciences, Oncology, & Genomics, Baltimore, Maryland, USA
| | - S Swaroop Vedula
- Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland, USA, 21218
| | - Susan A Cotter
- Southern California College of Optometry, 2575 Yorba Linda Boulevard, Fullerton, California, USA, 92831
| | - Donald O Mutti
- The Ohio State University, College of Optometry, 338 West Tenth Avenue, Columbus, Ohio, USA, 43210-1240
| | - Sueko M Ng
- Johns Hopkins Bloomberg School of Public Health, Department of Epidemiology, 615 N. Wolfe Street, W5010, c/o Cochrane Eyes and Vision Group, Baltimore, Maryland, USA, 21205
| | - J Daniel Twelker
- University of Arizona, Department of Ophthalmology, 655 North Alvernon Way Suite 108, Tucson, Arizona, USA, 85711
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Lam AKC, Hon Y, Leung SYY, Shu-Ho L, Chong J, Lam DCC. Association between long-term orthokeratology responses and corneal biomechanics. Sci Rep 2019; 9:12566. [PMID: 31467346 PMCID: PMC6715748 DOI: 10.1038/s41598-019-49041-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 08/19/2019] [Indexed: 12/22/2022] Open
Abstract
Myopia is very prevalent worldwide, especially among Asian populations. Orthokeratology is a proven intervention to reduce myopia progression. The current study investigated association between baseline corneal biomechanics and orthokeratology responses, and changes of corneal biomechanics from long-term orthokeratology. We fitted 59 adult subjects having myopia between −4.00D to −5.00D with overnight orthokeratology. Corneal biomechanics was measured through dynamic bidirectional corneal applanation (in terms of corneal hysteresis, CH and corneal resistance factor, CRF) and corneal indentation (in terms of corneal stiffness, S and tangent modulus, E). Subjects with poor orthokeratology responses had lower E (mean 0.474 MPa) than subjects with good orthokeratology responses (mean 0.536 MPa). Successful orthokeratology for 6 months resulted in reducing CH (reduced by 5.8%) and CRF (reduced by 8.7%). Corneal stiffness was stable, but E showed an increasing trend. Among subjects with successful orthokeratology, a higher baseline S resulted in greater myopia reduction (Pearson correlation coefficient, r = 0.381, p = 0.02).
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Affiliation(s)
- Andrew K C Lam
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China.
| | - Ying Hon
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong, China
| | - Stanley Y Y Leung
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Lu Shu-Ho
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Jones Chong
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - David C C Lam
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
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Lau JK, Wan K, Cheung SW, Vincent SJ, Cho P. Weekly Changes in Axial Length and Choroidal Thickness in Children During and Following Orthokeratology Treatment With Different Compression Factors. Transl Vis Sci Technol 2019; 8:9. [PMID: 31360614 PMCID: PMC6656409 DOI: 10.1167/tvst.8.4.9] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 05/13/2019] [Indexed: 12/13/2022] Open
Abstract
Purpose To determine the influence of compression factor upon changes in axial length and choroidal thickness during and following orthokeratology treatment. Methods Orthokeratology lenses of different compression factors (one eye with 0.75 D and the fellow eye with 1.75 D) were randomly assigned to 28 subjects (median [range] age: 9.3 [7.8–11.0] years). Ocular biometrics were measured weekly for 1 month of lens wear and after lens cessation until the refraction stabilized (mean duration: 2.8 ± 0.4 weeks). Changes between eyes, and the associations between axial shortening and choroidal thickening with other ocular biometrics were analyzed. Results There were no significant between-eye differences in the changes of ocular biometrics (all P > 0.05). After adjusting for paired-eye data, axial length initially decreased by 26 ± 41 μm (P = 0.03) at week 1, then gradually returned to its original length. An approximate antiphase relationship of choroidal thickness (mean change: 9 ± 12 μm, P < 0.001) with axial length was observed. A significant rebound in axial length, but not choroidal thickness, occurred during the cessation period. Central corneal thinning and choroidal thickening accounted for 70% of initial axial shortening. Conclusions Increasing the compression factor by 1.00 D did not affect changes in ocular biometrics in short-term orthokeratology. Significant axial shortening and choroidal thickening were observed during early treatment period. Axial shortening could not be entirely explained by central corneal thinning and choroidal thickening, which warrants further investigation. Translational Relevance Initial axial shortening in orthokeratology is transient and therefore axial length remains useful for long-term monitoring of axial elongation in children.
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Affiliation(s)
- Jason K Lau
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Kin Wan
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Sin-Wan Cheung
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Stephen J Vincent
- Contact Lens and Visual Optics Laboratory, School of Optometry and Vision Science, Queensland University of Technology, Brisbane, Australia
| | - Pauline Cho
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
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Lau JK, Vincent SJ, Cheung SW, Cho P. The influence of orthokeratology compression factor on ocular higher-order aberrations. Clin Exp Optom 2019; 103:123-128. [PMID: 31264269 DOI: 10.1111/cxo.12933] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 05/20/2019] [Accepted: 05/21/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND To investigate the influence of compression factor upon changes in ocular higher-order aberrations (HOAs) in young myopic children undergoing orthokeratology treatment. METHODS Subjects aged between six and < 11 years, with low myopia (0.50-4.00 D inclusive), low astigmatism (≤ 1.25 D), and anisometropia (≤ 1.00 D), were randomly assigned to wear orthokeratology lenses of different compression factors in each eye (one eye 0.75 D and the fellow eye 1.75 D). HOAs were measured weekly over one month of lens wear. Wavefront analysis was conducted over a 5-mm pupil using a sixth order Zernike polynomial expansion. Linear mixed models were used to examine the individual Zernike co-efficients and specific root-mean-square (RMS) error (spherical, comatic, total HOAs) metrics and their changes between the two eyes during the study period. RESULTS Twenty-eight myopic (mean manifest spherical equivalent refraction: -2.10 ± 0.58 D) children (median [range] age: 9.3 [7.8-11.0] years) were analysed. Significant interocular differences in HOAs at baseline were observed for Z 6 - 6 and Z 6 - 4 only (both p < 0.05). During the lens wear period, eyes fitted with the increased compression factor showed greater changes in primary spherical aberration ( Z 4 0 , p = 0.04) and RMS values for spherical and total HOAs (both p < 0.01). Considering data from both eyes together, after adjusting for the paired nature of the data, some other Zernike terms ( Z 3 1 and Z 6 0 , both p < 0.01) and the RMS value of comatic aberrations (p < 0.001) significantly increased after one month of orthokeratology treatment. The increase in primary spherical aberration ( Z 4 0 ) was positively correlated with the reduction in spherical equivalent refractive error, but only in eyes fitted with the increased compression factor (r = 0.69, p < 0.001). CONCLUSIONS Increasing the orthokeratology compression factor by 1.00 D significantly altered some HOAs, particularly spherical aberration. Given the association between positive spherical aberration and eye growth in children, further research investigating the influence of orthokeratology compression factor on axial eye growth is warranted.
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Affiliation(s)
- Jason K Lau
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region, China
| | - Stephen J Vincent
- Contact Lens and Visual Optics Laboratory, School of Optometry and Visual Science, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Sin-Wan Cheung
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region, China
| | - Pauline Cho
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hong Kong Special Administrative Region, China
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