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Nisha Singh, Chwee Hong Yeo, Archayeeta Rakshit, Nomitha Baanu, Madhavan Renjini, Viswanathan S, Jameel Rizwana Hussaindeen, Krishna Kumar Ramani, Meenakshi Swaminathan; Evaluation of the impact of low-addition progressive lenses on the accommodation and convergence functions in Indian population. Invest. Ophthalmol. Vis. Sci. 2017;58(8):317.
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© ARVO (1962-2015); The Authors (2016-present)
Low-addition progressive lenses have been well endorsed as a product for alleviating visual fatigue, yet there is ambiguity about its effect on the accommodative and convergence functions. Therefore, this study was aimed to evaluate the effect of low-addition (+0.40 D and +0.60 D) progressive lenses on the amplitude of accommodation (AA) and near point of convergence (NPC).
A randomized study in cross-over design was conducted on 82 subjects in each test lens group (+0.40 D and +0.60 D). For +0.40 D group, subjects were recruited from 19-29 years and for +0.60 D group from 30-37 years. Each subject wore test lenses (Essilor EyezenTM) and control lenses (single vision) for 4 weeks each in randomized order. Baseline measurement was taken with the subjects’ own glasses and then after wearing either the test lenses or control lenses. Both AA and NPC were measured binocularly using push-up technique with the RAF ruler. Average of three measurements was taken for the analysis.
Repeated measures ANOVA was used to compare the measurements after wearing the test, control lenses and baseline. NPC for +0.4D group measured at baseline (6.3 ±2.4), the control (5.9 ± 1.7) and test lenses (6.04 ± 2.4) were not statistically different (F (2, 76) = 1.67, p = 0.19). For +0.6 D, there was also no significant different (F (2, 58) = 1.53, p = 0.23) in NPC at baseline, after wearing control and test lenses (6.0 ± 1.6, 6.2 ± 1.9, and 6.5 ± 1.9, respectively).No significant difference was also found for AA in +0.40 D lens group at baseline, after wearing control and test lenses (10.8 ± 2.3, 11.2 ± 2.3, 11.5 ± 2.6, respectively; F (2, 76) = 2.32, p = 0.10) whereas for +0.60 D group the AA measured at baseline (7.1 ± 2.0), after control (7.9 ± 1.7) and test lenses (7.9 ± 3.2), was increase significantly after switching to either control or test lens (F (2, 82, p < 0.05). Post-hoc test (Fisher’s LSD) revealed significant difference between own glasses and test lens (p < 0.05) as well as control lens (p< 0.05) but no difference was found between test and control lenses (p = 0.87).
No difference in AA or NPC is found between low-addition progressive lenses and single vision lenses. Hence, low-addition progressive lenses do not impact the binocular functions of the eye.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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