An action video game for the treatment of amblyopia in children: A feasibility study

Abstract

The gold-standard treatment for childhood amblyopia remains patching or penalizing the fellow eye, resulting in an average of about a one line (0.1 logMAR) improvement in visual acuity following ≈120 h of patching in children 3-8 years old. However, compliance with patching and other treatment options is often poor. In contrast, fast-paced action video games can be highly engaging, and have been shown to yield broad-based improvements in vision and attention in adult amblyopia. Here, we pilot-tested a custom-made action video game to treat children with amblyopia. Twenty-one (n = 21) children (mean age 9.95 ± 3.14 [se]) with unilateral amblyopia (n = 12 anisometropic and n = 9 strabismic) completed 20 h of game play either monocularly, with the fellow eye patched (n = 11), or dichoptically, with reduced contrast to the fellow eye (n = 10). Participants were assessed for visual acuity (VA), stereo acuity and reading speed at baseline, and following 10 and 20 h of play. Additional exploratory analyses examined improvements after 6-10 weeks of completion of training (follow-up). Following 20 h of training, VA improved, on average, by 0.14 logMAR (≈38%) for the dichoptic group and by 0.06 logMAR (≈15%) for the monocular group. Similarly, stereoacuity improved by 0.07 log arcsec (≈17%) following dichoptic training, and by 0.06 log arcsec (≈15%) following monocular training. Across both treatment groups, 7 of the 12 individuals with anisometropic amblyopia showed improvement in stereoacuity, whereas only 1 of the 9 strabismic individuals improved. Most improvements were largely retained at follow-up. Our feasibility study therefore suggests that the action video game approach may be used as an effective adjunct treatment for amblyopia in children, achieving results similar to those of the gold-standard treatment in shorter duration.

Keywords: Amblyopia; Children; Dichoptic; Patching; Perceptual learning; Video games.

Figure 1

Study design. Total number of participants included in each portion of the study (n), further divided into anisometropic amblyopes (A) and strabismic amblyopes (S).

Figure 2

Screenshots from the custom-made child-friendly action video game. Top Left: Children in the dichoptic game play group aligned the game with a mirror stereoscope. Top right: Dichoptic display showing the image sent to the AE on the left and that sent to the NAE on the right, in the Magical Garden game world; during set-up, children adjusted the mirrors and contrast level of the NAE image, such that both images of the stereoscope were visible. Bottom Panels: The lower two screenshots show the two other game worlds, Amblyopia World (top) and Chinatown (bottom); Various games were included in order to keep the children engaged for as many as 20 hours.

Figure 3

Dichoptic alignment: Fusion was achieved by aligning dichoptic horizontal and vertical lines to make a cross. A high contrast border and additional squares presented to both eyes provided context to aid in this process.

Figure 4

Box plots showing change in performance for visual acuity (top panels), stereoacuity (middle panels) and MN read (bottom panels). In each boxplot, the center horizontal bar is the median, the box shows the semi-interquartile range, and the whiskers the 9th and 91st percentile. Change scores are shown following 10 hours (left plots) and 20 hours (right plots) of training, relative to baseline. Changes are shown for monocular (filled symbols) and dichoptic (open symbols) training participants. Color- and shape-coding denotes amblyopia type: aniso (blue, circle) or strab (red, square). The number of participants contributing to each measurement is reported at the bottom of each plot. Note that the horizontal positions of the data points have been jittered to avoid overlap.

Figure 5. In-game IOR Data. Top

IOR as a function of hours of videogame play for anisometric (N=5 out of 6) and strabismic (N = 4) patients separately as well as for comparable data from our recent study in adults (dotted line - Vedamurthy et al., 2015). Middle: Improvement in VA as a function of changes in IOR from 0 to 20 hours of game play (except for A9). Bottom: improvement in stereo acuity as a function of changes in IOR from 0 to 20 hours of game play. Blue – data from anisometric participants. Red – data from strabismic participants. The data of observer A9 is highlighted in the two lower panels because IOR was only recorded for the first 10 hours).

Figure 6

VA improvement data (pre-post) from previous studies examining treatments in children with amblyopia, as a function of hours of treatment. Solid gray symbols represent monocular perceptual learning or video game treatment. Black symbols show patching treatment; open symbols indicate dichoptic/binocular treatment. The blue symbols are from the current study. The lines in Figure 6 show the time course of monitored occlusion (solid line) and the 95% confidence intervals (dotted lines - from Stewart et al., 2007).

Figure 7

Comparison of children and adult gains following action video game play. Gains in visual acuity (pre-post) as a function of hours of training for current study in children (square symbols) and for our previous study in adults (diamond symbols; Vedamurthy et al., 2015)