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Chun RKM, Zhang H, Liu Z, Tse DYY, Zhou Y, Lam CSY, To CH. Defocus incorporated multiple segments (DIMS) spectacle lenses increase the choroidal thickness: a two-year randomized clinical trial. Eye Vis (Lond) 2023; 10:39. [PMID: 37715201 PMCID: PMC10502972 DOI: 10.1186/s40662-023-00356-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 08/22/2023] [Indexed: 09/17/2023]
Abstract
BACKGROUND Myopia control interventions, such as defocus incorporated multiple segments (DIMS) spectacle lenses, have been adopted in school-aged children to reduce the prevalence of myopia and its complications. This study aimed to investigate the effect of DIMS spectacle lenses on subfoveal choroidal thickness (SfChT) over a period of two years, as the choroidal response to myopic control is a crucial factor in exploring its potential effect on predicting myopia progression. METHODS This study involved a secondary analysis of our previous randomized clinical trial. Myopic school-aged children aged 8-13 years were recruited in a two-year study investigating the effect of DIMS spectacle lenses on myopia progression. The treated group received DIMS spectacle lenses (n = 78), while the control group was treated with a pair of single vision (SV) spectacle lenses (n = 80). SfChT was monitored at 1 week, 1, 3, 6, 12, 18 and 24 months post lens wear using spectral-domain optical coherence tomography and a custom made auto-segmentation algorithm utilizing convolutional neural networks. RESULTS SfChT increased significantly after one week of DIMS spectacle lens wear compared to those wearing SV spectacle lenses (adjusted mean change relative to baseline ± SEM at one week; DIMS vs. SV, 6.75 ± 1.52 µm vs. - 3.17 ± 1.48 µm; P < 0.0001, general linear model). The thickness of choroid increased to 13.64 ± 2.62 µm after 12 months of DIMS lens wear while the choroid thinned in SV group (- 9.46 ± 2.55 µm). Choroidal changes demonstrated a significant negative association with axial elongation over two years in both the DIMS and SV groups. Choroidal change at three months significantly predicted the changes in AL at 12 months after controlling the effect of age and gender. CONCLUSIONS Our study demonstrated a significant choroidal thickening in response to myopic defocus incorporated in a spectacle lens after one week of lens wear, sustained over the two-year study period. The results suggested that choroidal changes at three months may help predict changes in axial length after one year. Trial registration ClinicalTrials.gov. Myopia control with the multi-segment lens. NCT02206217. Registered 29 July 2014, https://clinicaltrials.gov/ct2/show/study/NCT02206217.
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Affiliation(s)
- Rachel Ka Man Chun
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Kowloon, Hong Kong, China.
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Shatin, Hong Kong, China.
| | - Hanyu Zhang
- School of Medicine, Nankai University, Tianjin, China
| | - Zhengji Liu
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - Dennis Yan Yin Tse
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Shatin, Hong Kong, China
| | - Yongjin Zhou
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
- School of Biomedical Engineering, Department of Medical Electronics, Shenzhen University, Shenzhen, China
| | - Carly Siu Yin Lam
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Shatin, Hong Kong, China
| | - Chi Ho To
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
- Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Shatin, Hong Kong, China
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Radhakrishnan H, Lam CSY, Charman WN. Multiple segment spectacle lenses for myopia control. Part 1: Optics. Ophthalmic Physiol Opt 2023; 43:1125-1136. [PMID: 37378657 DOI: 10.1111/opo.13191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 05/27/2023] [Accepted: 06/10/2023] [Indexed: 06/29/2023]
Abstract
PURPOSE To understand and compare the optics of two multiple segment (MS) spectacle lenses (Hoya MiyoSmart and Essilor Stellest) designed to inhibit myopia progression in children. METHODS The optics of the two designs are presented, together with geometrical optics-based calculations to understand the impact of the lenses on the optics of the eye. Lenses were evaluated with three techniques: surface images, Twyman-Green interferometry and focimetry. The carrier lens powers and the spatial distribution, powers and forms of the lenslets were measured. RESULTS MS lenses as manufactured were found to match most of the design specifications provided by their manufacturers, although some apparent small discrepancies were found. The focimeter-measured power of the lenslets was approximately +3.50 D for the MiyoSmart and +4.00 D for the highly aspheric lenslets of the Stellest design. For both lens designs, image contrast would be expected to become modestly reduced in the focal planes of the distance-correcting carrier lenses. Images become much more degraded in the combined carrier-lenslet focal plane, due to the generation of multiple laterally displaced images formed by adjacent lenslets within the effective pupil. The exact effects observed depended on the effective pupil size and its location with respect to the lenslets, as well as the power and arrangement of the lenslets. CONCLUSION Wearing either of these lenses will produce broadly similar effects on retinal imagery.
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Affiliation(s)
- Hema Radhakrishnan
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Carly Siu Yin Lam
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
- Centre for Eye and Vision Research (CEVR), Hong Kong SAR, China
| | - W Neil Charman
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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Radhakrishnan H, Lam CSY, Charman WN. Multiple segment spectacle lenses for myopia control. Part 2: Impact on myopia progression. Ophthalmic Physiol Opt 2023; 43:1137-1144. [PMID: 37378880 DOI: 10.1111/opo.13194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 05/27/2023] [Accepted: 06/10/2023] [Indexed: 06/29/2023]
Abstract
PURPOSE Initial studies have suggested that multiple segment (MS) spectacle lenses can reduce the progression rate of childhood myopia and axial eye growth. This paper aimed to compare the effectiveness of two different available designs of MS lens and to explore the nature of their control effect. METHOD Published data from the only two clinical trials in which changes in mean spherical equivalent refraction (SER) and axial length (AL) for matched groups of myopic children wearing either MS or single-vision (SV) spectacle corrections, recorded over a period of at least 2 years, were further analysed and compared. Both trials involved Chinese children of similar ages and visual characteristics, but the trials were located in different cities. The two MS lenses examined were MiyoSmart or DIMS (Hoya) and Stellest (Essilor). RESULTS Absolute changes in SER and AL differed over time during the two trials. However, if the results were expressed in terms of efficacy over successive 6-month periods, then the two MS lenses produced broadly similar results (initial efficacy for the control of myopia progression of about 60%-80%, declining over 2 years to about 35%-55%). Control appears to be absolute rather than proportional. DISCUSSION Myopia control may be due to either the additional myopic defocus induced by the MS lenses (i.e., asymmetry of the through-focus image changes about the distance focus) or to the general reduction in image contrast that the lenslets create in the peripheral field. CONCLUSION Multiple segment spectacle lenses offer a valuable new approach to the control of myopia progression in children. Further work is required to clarify their mechanism of action and to optimise their design parameters.
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Affiliation(s)
- Hema Radhakrishnan
- School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Carly Siu Yin Lam
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
- Centre for Eye and Vision Research (CEVR), Hong Kong SAR, China
| | - W Neil Charman
- School of Health Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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Zhang HY, Lam CSY, Tang WC, Lee PH, Tse DY, To CH. Changes in relative peripheral refraction in children who switched from single-vision lenses to Defocus Incorporated Multiple Segments lenses. Ophthalmic Physiol Opt 2023; 43:319-326. [PMID: 36583393 DOI: 10.1111/opo.13086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/31/2022]
Abstract
PURPOSE To investigate changes in relative peripheral refraction (RPR) associated with myopia progression in children who wore single-vision (SV) lenses for 2 years and switched to Defocus Incorporated Multiple Segments (DIMS) lenses in the third year versus children who wore DIMS lenses for 3 years. METHODS In the first 2 years, children were allocated randomly to wear either DIMS or SV lenses. In the third year, children in the DIMS group continued to wear these lenses, while those in the SV group were switched to DIMS lenses (Control-to-DIMS group). Central and peripheral refraction and axial length were monitored every 6 months. RESULTS Over 3 years, the DIMS group (n = 65) showed good myopia control and maintained a relatively constant and symmetrical RPR profile without significant changes. In the first 2 years, children who wore SV lenses (n = 55) showed asymmetrical RPR changes, with significant increases in hyperopic RPR at 20° nasal (N) (mean difference: 0.88 ± 1.06 D, p < 0.0001) and 30N (mean difference: 1.07 ± 1.09 D, p < 0.0001). The Control-to-DIMS group showed significant myopia retardation after wearing DIMS lenses in the third year. When compared with the RPR changes in the first 2 years, significant reductions in hyperopic RPR were observed at 20N (mean difference: -1.14 ± 1.93 D, p < 0.0001) and 30N (mean difference: -1.07 ± 1.17 D, p < 0.0001) in the third year. However, no significant difference between the RPR changes found in the nasal retina and temporal retina (p > 0.05) was noted in the third year. CONCLUSION Symmetrical changes in RPR were found in children switching from SV to DIMS lenses, and a symmetrical pattern of RPR was noted in children who wore DIMS for 3 years. Myopia control using myopic defocus in the mid-periphery influenced the RPR changes and retarded myopia progression by altering the eye's growth pattern.
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Affiliation(s)
- Han Yu Zhang
- School of Medicine, Nankai University, Tianjin, China
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR
- Centre for Eye and Vision Research (CEVR), Shatin, Hong Kong SAR
| | - Carly Siu Yin Lam
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR
- Centre for Eye and Vision Research (CEVR), Shatin, Hong Kong SAR
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR
| | - Wing Chun Tang
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR
| | - Paul H Lee
- Southampton Clinical Trials Unit, University of Southampton, Southampton, UK
| | - Dennis Y Tse
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR
- Centre for Eye and Vision Research (CEVR), Shatin, Hong Kong SAR
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR
| | - Chi Ho To
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR
- Centre for Eye and Vision Research (CEVR), Shatin, Hong Kong SAR
- Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR
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Lam CSY, Tang WC, Zhang HY, Lee PH, Tse DYY, Qi H, Vlasak N, To CH. Long-term myopia control effect and safety in children wearing DIMS spectacle lenses for 6 years. Sci Rep 2023; 13:5475. [PMID: 37015996 PMCID: PMC10073092 DOI: 10.1038/s41598-023-32700-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 03/31/2023] [Indexed: 04/06/2023] Open
Abstract
This study evaluated the long-term myopia control effect and safety in children wearing Defocus Incorporated Multiple Segments (DIMS) spectacle lenses. Participants who completed the 2-year RCT were followed for a total of 6 years; their cycloplegic refractions and axial length were measured. Group 1 (n = 36) wore DIMS spectacles for 6 years; Group 2 (n = 14) wore DIMS lens for the first 3.5 years and SV spectacles afterwards; Group 3 (n = 22) wore SV spectacles in the first 2 years and switched to DIMS; Group 4 (n = 18) wore SV spectacles in the first 2 years, switched to DIMS for 1.5 years and then SV spectacles again. Group 1 showed no significant differences in myopia progression (- 0.52 ± 0.66 vs. - 0.40 ± 0.72D) and axial elongation (0.32 ± 0.26 vs. 0.28 ± 0.28 mm, both p > 0.05) between the first and the later 3 years. In the last 2.5 years, DIMS lens groups (Groups 1 and 3) had less myopia progression and axial elongation than the single vision groups (Groups 2 and 4). There was no evidence of rebound after stopping the treatment. Post-wear visual functions in all groups were within norms. The results supported that DIMS lenses provided sustained myopia control without adverse effects over the 6-year study period.Trial registration: clinicaltrials.gov; NCT02206217.
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Affiliation(s)
- Carly Siu Yin Lam
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
- Centre for Eye and Vision Research, Sha Tin, Hong Kong.
| | - Wing Chun Tang
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Han Yu Zhang
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
- School of Medicine, Nankai University, Tianjin, China
| | - Paul H Lee
- Southampton Clinical Trials Unit, University of Southampton, Southampton, UK
| | - Dennis Yan Yin Tse
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
- Centre for Eye and Vision Research, Sha Tin, Hong Kong
| | - Hua Qi
- Technical Research and Development Department, Hoya Vision Care, Tokyo, Japan
| | - Natalia Vlasak
- Technical Research and Development Department, Hoya Vision Care, Amsterdam, The Netherlands
| | - Chi Ho To
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
- Centre for Eye and Vision Research, Sha Tin, Hong Kong
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Lam CSY, Tang WC, Qi H, Radhakrishnan H, Hasegawa K, To CH, Charman WN. Effect of Defocus Incorporated Multiple Segments Spectacle Lens Wear on Visual Function in Myopic Chinese Children. Transl Vis Sci Technol 2020; 9:11. [PMID: 32879767 PMCID: PMC7442864 DOI: 10.1167/tvst.9.9.11] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 06/24/2020] [Indexed: 12/16/2022] Open
Abstract
Purpose To compare visual function of myopic children who had worn either defocus incorporated multiple segment (DIMS) spectacle lenses or single vision (SV) spectacle lenses over two years. Methods We included 160 Chinese myopic (−1 diopter [D] to −5 D) children aged 8 to 13 years in a randomized clinical trial; they wore either DIMS lenses (DIMS; n = 79) or regular SV spectacles lenses (n = 81) full time for 2 years. Visual function, including high-contrast visual acuity (VA) and low-contrast VA at distance and near, binocular functions, and accommodation, before, during, and after 2 years of spectacle wear were assessed when both groups wore SV corrections. Changes of visual function between the two groups and within groups were compared. Results There were no statistically significant differences in the 2-year visual function changes between DIMS and SV groups (repeated measures analysis of variance with group as factor; P > 0.05). Statistically significant improvement in the best-corrected distance high-contrast VA (P < 0.001) and stereoacuity score (P < 0.001) were found after DIMS lens wear over 2 years. Similar findings were observed after SV spectacle lens wear. For both the DIMS and SV groups, there were statistically significant decreases in accommodative lag, monocular and binocular amplitude of accommodation after two years (P < 0.01), but not in the changes in distance low-contrast VA, near high-contrast VA, near low-contrast VA, or phoria. Conclusions Although changes in some visual function were shown during 2 years of DIMS lens wear, similar changes were found with SV lens wear. Wear of DIMS spectacle lenses for 2 years does not adversely affect major visual function when children return to SV corrections. Translational Relevance DIMS spectacle lenses did not cause any adverse effects on visual function.
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Affiliation(s)
- Carly Siu Yin Lam
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Wing Chun Tang
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Hua Qi
- Technical Research and Development Department, Vision Care Section, Hoya Corporation, Tokyo, Japan
| | - Hema Radhakrishnan
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Keigo Hasegawa
- Technical Research and Development Department, Vision Care Section, Hoya Corporation, Tokyo, Japan
| | - Chi Ho To
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - W Neil Charman
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
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Zhang HY, Lam CSY, Tang WC, Leung M, To CH. Defocus Incorporated Multiple Segments Spectacle Lenses Changed the Relative Peripheral Refraction: A 2-Year Randomized Clinical Trial. Invest Ophthalmol Vis Sci 2020; 61:53. [PMID: 32460315 PMCID: PMC7405698 DOI: 10.1167/iovs.61.5.53] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 04/06/2020] [Indexed: 12/24/2022] Open
Abstract
Purpose To compare changes in relative peripheral refraction (RPR) associated with myopia progression in myopic children wearing Defocus Incorporated Multiple Segments (DIMS) lenses and single vision (SV) spectacle lenses over 2 years. Methods A 2-year double-blind, randomized controlled trial was conducted on 183 myopic children. Subjects were allocated to either wearing DIMS (n = 93) or SV spectacle lenses (n = 90). Peripheral refraction at 10°, 20°, and 30° of the nasal (10N, 20N, 30N) and temporal (10T, 20T, 30T) retinal eccentricities, central refraction, and axial length after cycloplegia were monitored every 6 months. Results DIMS group showed symmetrical peripheral myopic shifts between the nasal and temporal retina (comparing myopic shifts between the nasal and temporal retina, the difference between the corresponding eccentricities were nonclinically significance). SV group showed asymmetrical peripheral myopic shifts between the nasal and temporal retina, with more myopic shifts (all P ≤ 0.001) at 10T (-0.32 ± 0.62 diopters [D]), at 20T (-0.69 ± 0.95 D), and 30T (-0.85 ± 1.52 D). No significant changes in RPR spherical equivalent (M) were noted in the DIMS group, whereas significant increases (all P < 0.0001) in hyperopic RPR M were observed at 10N (0.27 ± 0.45 D), 20N (0.75 ± 0.72 D), and 30N (0.98 ± 0.76 D) in the SV group. Conclusions Wearing DIMS lenses resulted in a significantly different peripheral refraction profile and RPR changes, as well as significant myopia control effects when compared with SV lenses. Myopia control adopting myopic defocus in the midperiphery influenced peripheral refraction and slowed central myopia progression, most likely through alteration of overall retinal shape.
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Affiliation(s)
- Han Yu Zhang
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Carly Siu Yin Lam
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Wing Chun Tang
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Myra Leung
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
- Discipline of Optometry and Vision Science, Faculty of Health, University of Canberra, Canberra, Australia
| | - Chi Ho To
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
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Lam CSY, Tang WC, Tse DYY, Lee RPK, Chun RKM, Hasegawa K, Qi H, Hatanaka T, To CH. Defocus Incorporated Multiple Segments (DIMS) spectacle lenses slow myopia progression: a 2-year randomised clinical trial. Br J Ophthalmol 2020; 104:363-368. [PMID: 31142465 PMCID: PMC7041503 DOI: 10.1136/bjophthalmol-2018-313739] [Citation(s) in RCA: 188] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 04/01/2019] [Accepted: 05/10/2019] [Indexed: 11/17/2022]
Abstract
AIM To determine if 'Defocus Incorporated Multiple Segments' (DIMS) spectacle lenses slow childhood myopia progression. METHODS A 2-year double-masked randomised controlled trial was carried out in 183 Chinese children aged 8-13 years, with myopia between -1.00 and -5.00 D and astigmatism ≤1.50 D. Children were randomly assigned to wear DIMS (n=93) or single vision (SV) spectacle lenses (n=90). DIMS lens incorporated multiple segments with myopic defocus of +3.50 D. Refractive error (cycloplegic autorefraction) and axial length were measured at 6month intervals. RESULTS 160 children completed the study, n=79 in the DIMS group and n=81 in the SV group. Average (SE) myopic progressions over 2 years were -0.41±0.06 D in the DIMS group and -0.85±0.08 D in the SV group. Mean (SE) axial elongation was 0.21±0.02 mm and 0.55±0.02 mm in the DIMS and SV groups, respectively. Myopia progressed 52% more slowly for children in the DIMS group compared with those in the SV group (mean difference -0.44±0.09 D, 95% CI -0.73 to -0.37, p<0.0001). Likewise, children in the DIMS group had less axial elongation by 62% than those in the SV group (mean difference 0.34±0.04 mm, 95% CI 0.22 to 0.37, p<0.0001). 21.5% children who wore DIMS lenses had no myopia progression over 2 years, but only 7.4% for those who wore SV lenses. CONCLUSIONS Daily wear of the DIMS lens significantly retarded myopia progression and axial elongation in myopic children. Our results demonstrated simultaneous clear vision with constant myopic defocus can slow myopia progression. TRIAL REGISTRATION NUMBER NCT02206217.
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Affiliation(s)
- Carly Siu Yin Lam
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Wing Chun Tang
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Dennis Yan-Yin Tse
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Roger Pak Kin Lee
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | - Rachel Ka Man Chun
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
| | | | - Hua Qi
- Hoya Corporation, Tokyo, Japan
| | | | - Chi Ho To
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Hong Kong
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Lam CSY, Tang WC, Tse DYY, Tang YY, To CH. Defocus Incorporated Soft Contact (DISC) lens slows myopia progression in Hong Kong Chinese schoolchildren: a 2-year randomised clinical trial. Br J Ophthalmol 2013; 98:40-5. [PMID: 24169657 PMCID: PMC3888618 DOI: 10.1136/bjophthalmol-2013-303914] [Citation(s) in RCA: 203] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Aims To determine if ‘Defocus Incorporated Soft Contact’ (DISC) lens wear slows childhood myopia progression. Methods A 2-year double-blind randomised controlled trial was carried out in 221 children aged 8–13 years, with myopia between −1.00 and −5.00 Dioptres (D) and astigmatism ≤1.00 D. Subjects were randomly assigned to the DISC (n=111) or single vision (SV; n=110) contact lens group. DISC lenses incorporated concentric rings, which provided an addition of +2.50 D, alternating with the normal distance correction. Refractive error (cycloplegic autorefraction) and axial length were measured at 6-month intervals. Differences between groups were analysed using unpaired t test. Results In total, 128 children completed the study, n=65 in the DISC group and n=63 in the SV group. Myopia progressed 25% more slowly for children in the DISC group compared with those in the control group (0.30 D/year; 95% CI −0.71 to −0.47 vs 0.4 D/year; 95% CI −0.93 to −0.65, p=0.031). Likewise, there was less axial elongation for children in the DISC versus SV groups (0.13 mm/year; 95% CI 0.20 to 0.31 vs 0.18 mm/year; 95% CI 0.30 to 0.43, p=0.009). Treatment effect correlated positively with DISC lens wearing time (r=0.342; p=0.005). Indeed, myopia in children who wore the DISC lenses for five or more hours/day progressed 46% (mean difference=−0.382 D, p=0.001; 95% CI −0.59 to −0.17) less than those in the SV group. Conclusions The daily wearing of DISC lens significantly slowed myopia progression and axial elongation in Hong Kong schoolchildren. The findings demonstrated that simultaneous clear vision with constant myopic defocus can retard myopia progression.
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Affiliation(s)
- Carly Siu Yin Lam
- Centre for Myopia Research, School of Optometry, The Hong Kong Polytechnic University, , Hung Hom, Kowloon, Hong Kong
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Choi SW, Benzie IFF, Lam CSY, Chat SWS, Lam J, Yiu CH, Kwan JJ, Tang YH, Yeung GSP, Yeung VTF, Woo GC, Hannigan BM, Strain JJ. Inter-relationships between DNA damage, ascorbic acid and glycaemic control in Type 2 diabetes mellitus. Diabet Med 2005; 22:1347-53. [PMID: 16176195 DOI: 10.1111/j.1464-5491.2005.01647.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
AIMS The onset of complications in Type 2 diabetes mellitus (DM) patients cannot be predicted in individuals. Evidence suggests a link between complications and hyperglycaemia, oxidative stress and antioxidants, but causality is unclear. This study investigated baseline (entry) fasting plasma ascorbic acid, lymphocytic DNA damage and glycaemic control in Type 2 DM as part of a long-term study, the aim of which is to explore a biomarker profiling approach to identify and improve outcome in high-risk subjects. METHODS A cross-sectional study, in which DNA damage, glycated haemoglobin (HbA(1c)), fasting plasma glucose (FPG) and ascorbic acid (AA) were measured on fasting blood samples collected from 427 Type 2 DM subjects. RESULTS DNA damage was significantly (P < 0.0001) and directly correlated to both FPG (r = 0.540) and HbA(1c) (r = 0.282), and was significantly (P < 0.0001), independently and inversely correlated to plasma AA (r = -0.449). In those subjects with both poor glycaemic control and low AA (< 48 microm, the overall mean value for the study group), DNA damage was significantly (P < 0.005) higher compared with those subjects with a similar degree of hyperglycaemia but with AA above the mean. CONCLUSIONS The novel finding of a significant inverse relationship between plasma AA and DNA damage in Type 2 DM indicates that poorly controlled diabetic subjects might benefit from increased dietary vitamin C. The data also have important implications for biomarker profiling to identify those subjects who might benefit most from intensive therapy. Longer-term follow-up is underway.
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Affiliation(s)
- S W Choi
- Faculty of Health and Social Sciences, The Hong Kong Polytechnic University, Kowloon, Hong Kong
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Abstract
PURPOSE This study aims to investigate genetic and environmental influences on physiological myopia by studying the difference in myopia prevalence between local schools and international schools in Hong Kong. METHODS Vision screening was carried out in local and international schools for students 13 to 15 years old. Types of refractive error were identified by visual acuity measurement, the presence of spectacles, a simple refraction, and the use of plus and minus ophthalmic lenses. RESULTS Three local schools and six international schools participated in the study. Two hundred eighty-nine students were from the local schools, and 789 students were from the international schools. Prevalence of myopia at the local schools ranged from 85 to 88%, whereas it ranged from 60 to 66% in the international schools. Students in the international schools were subdivided into Chinese origin, white, mixed Chinese, and Asian. Prevalence of myopia was highest in the Chinese group (82.8%) and lowest in the white group (40.5%). There was no age or gender difference in the prevalence of myopia. CONCLUSIONS Hong Kong Chinese students had a higher prevalence of myopia regardless of whether they studied in local or international schools when compared with other ethnic groups, such as whites. This further supports a genetic input into myopia development.
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Affiliation(s)
- Carly Siu Yin Lam
- Centre for Myopia Research, Department of Optometry and Radiography, The Hong Kong Polytechnic University, Hong Kong, China.
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Edwards MH, Lam CSY. The epidemiology of myopia in Hong Kong. Ann Acad Med Singap 2004; 33:34-8. [PMID: 15008559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
INTRODUCTION The prevalence of myopia amongst the Chinese has escalated in recent decades. While this refractive error was previously a little more than an inconvenience and a source of unwanted expense to the affected individuals, it is now sufficiently prevalent to warrant national concern. Myopia is also a major cause of low vision. This review aims to provide information on the prevalence of myopia in the Chinese community in Hong Kong. MATERIALS AND METHODS Based on a number of studies carried out mainly at the Centre for Myopia Research in The Hong Kong Polytechnic University, myopia in the Chinese community in Hong Kong is described. RESULTS Infants in Hong Kong appear to have refractive errors similar to infants of European descent; however, by the age of 7 years myopia is already prevalent. The annual incidence of myopia thereafter averages 11% to 12%; by the age of 17 years more than 70% are myopic, and this prevalence is greater than in people of European descent. In Hong Kong, myopia is much less prevalent in the older generation. CONCLUSION The increase in prevalence of myopia over a short period of time is postulated to be due to environmental factors. Children of Chinese descent have a susceptibility to environmental factors which cause myopia.
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Affiliation(s)
- M H Edwards
- Centre for Myopia Research, Department of Optometry and Radiography, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
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