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Raman Prasad Sah, Mateusz Tomasz Jaskulski, Arthur Bradley, Pete S Kollbaum; Accommodative lags and Reduced Image Quality in Children viewing personal electronic devices. Invest. Ophthalmol. Vis. Sci. 2019;60(9):3174. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Underaccommodation is common, resulting in accommodative lags that can be large in children. We examined accommodative behavior, and the image consequences of lags while children viewed different targets displayed on personal electronic devices.
Using the Grand Seiko auto-refractor, right eye spherical refractive states were measured 35 times per condition at 5Hz while children (7-16 years) viewed targets on an iPhone programmed to display 7mm tall high contrast black text displayed within a central rectangular window at distances of 1m, 0.33m and 0.2m. Eleven emmetropic children viewed the display binocularly (environmentally natural stimulus condition) and monocularly. Measured accommodative lags, measured pupil diameters and published monochromatic and chromatic aberration data were used to simulate polychromatic retinal images of logMAR charts at each viewing distance using custom Matlab optical simulation software. Visual acuity of masked subjects was measured in a randomized order using these simulated chart images.
All children exhibited lags at near, which were on average -0.59, -0.73, and -0.36 diopters binocularly, and -0.54, -0.80, -0.70 diopters monocularly at 1m, 0.33m, and 0.2m, respectively. Average pupil sizes decreased from 5.08mm at 1m to 3.86mm and 3.34mm at 0.33m and 0.2m with binocular viewing, and from 5.57mm to 4.73mm and 3.85mm with monocular viewing. At 1m, 0.33m, and 0.2m, defocus caused by accommodative lags observed during binocular viewing increased logMAR visual acuity thresholds by 0.42, 0.36, and 0.07 log units, respectively, and by 0.38, 0.48 and 0.25 log units with monocular viewing.
1M text (subtends 5 arc minutes at 1 meter) viewed at 0.33 and 0.20 m has logMAR sizes of 0.5 and 0.7, more than twice the size of the minimum resolvable text even in presence of accommodative lag, indicating that accommodative lags in these children will not prevent them from proficiently reading small text displayed on personal electronic devices.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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