iPad Activity Measures Interocular Brightness Disparity, Detects Amblyopia

Girl using a digital tablet in the room
Girl of five years,Japan
The device appears more cost effective and accessible than others used to detect amblyopia.

Interocular brightness disparity (IBD), visual acuity, and color vision can be measured in children as young as 3 years old by playing a game on a mobile device. These measurements can be used to detect unilateral amblyopia, according to findings published in Eye.

The study included 208 participants aged 3 to 14 years. Researchers obtained uniocular acuities, both with and without a pinhole, color vision using a tablet computer, and IBD. Participants looked through polarizing filters and chose the brighter of 2 images (spaceships) to assess IBD. Investigators determined variation of the differential brightness of image pairs using a staircase algorithm until participants perceived equal brightness. The study authors later confirmed unilateral amblyopia in 2 participants. 

The study found that binocular brightness balance on the tablet identified patients with amblyopia with 100% sensitivity and specificity. Researchers used visual acuity pinhole testing to distinguish patients with amblyopia from their non amblyopic peers. Only 1 patient with amblyopia was detected. The mean difference between tablet and E-Chart visual acuities with pinhole was 0.02 logMAR, with limits of agreement from -0.08 to +0.11 logMAR. Identical results were produced using the tablet and printed plates color vision testing. Testing times were brief, exit pleasure responses were positive, and testing times were obtained for brightness sense (mean 32.7 seconds, range 12-63 seconds), color vision (mean 52.8 seconds, range 17-95 seconds), and visual acuity (mean 88.75 seconds, range 41-188 seconds). 

Researchers highlight the convenience and cost effectiveness of utilizing this method to detect amblyopia. While other screening devices exist, they note that “these devices are expensive and not widely available in schools and pediatric offices, and are not readily applicable to telemedicine.” 

Study limitations include a single center design.


Kane SA, Gaspich M, Kane J, Weitzman SA, Hofeldt A. Automated vision screening of children using a mobile graphic device.Eye (Lond). Published online December 6, 2021. doi:10.1038/s41433-021-01862-x