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Compact Lens-less Digital Holographic Microscope for MEMS Inspection and Characterization
Published on: July 5, 2016
Effects of Progressive Addition Lens Wear on Digital Work in Pre-presbyopes
Chea-Su Kee1, Tsz Wing Leung1, Ka-Hung Kan1
1School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
Significance:
Growing popularity of handheld digital devices imposes significant challenges to our visual system and clinical management. This study aimed to determine the effects of lens design on parameters that may influence the refractive management of pre-presbyopic adult computer users.
Purpose:
To determine the effects of wearing conventional single-vision lenses (SVL) versus progressive addition lenses (PAL) on the working distance and refractive status.
Methods:
Adult computer users, recruited from two age cohorts (18 to 25 years, n = 19; 30 to 40 years, n = 45), were prescribed SVLs and PALs designed for use with handheld digital devices. For each lens type, the working distance and refractive shift (post-task - pre-task) were measured immediately after lens delivery (T0) and after 1 month of lens wear (T1). Working distances were recorded with an automatic ultrasound device while the participants were playing a video game. Refractive status through the subjects' glasses was measured before (pre-task) and after playing the game (post-task). Questionnaires assessing the frequencies of 10 digital work-related visual symptoms were conducted for both lens types at T1.
Results:
Switching from SVL to PAL increased the working distance in both cohorts (mean ± SEM = 1.88 ± 0.60 cm; P = .002) and induced a small but significant positive refractive shift (+0.08 ± 0.04 D, P = .021) in the older cohort at T1. In the younger cohort, the changes in working distance due to the switching lens design were correlated with myopic error (r = +0.66, P = .002). In the older cohort, the changes in refractive shift due to switching lens design were correlated with amplitude of accommodation at both time points (r for T0 and T1 = -0.32 and -0.30, respectively; both P < .05). Progressive addition lens was rated as causing less "increased sensitivity to light" compared with SVL.
Conclusions:
Switching from SVL to PAL increased the working distance and induced a positive refractive shift in the majority of pre-presbyopic adults.
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