Improved Binocular Outcomes Following Binocular Treatment for Childhood Amblyopia

Abstract

PurposeChildhood amblyopia can be treated with binocular games or movies that rebalance contrast between the eyes, which is thought to reduce depth of interocular suppression so the child can experience binocular vision. While visual acuity gains have been reported following binocular treatment, studies rarely report gains in binocular outcomes (i.e., stereoacuity, suppression) in amblyopic children. Here, we evaluated binocular outcomes in children who had received binocular treatment for childhood amblyopia.MethodsData for amblyopic children enrolled in two ongoing studies were pooled. The sample included 41 amblyopic children (6 strabismic, 21 anisometropic, 14 combined; age 4–10 years; ≤4 prism diopters [PD]) who received binocular treatment (20 game, 21 movies; prescribed 9–10 hours treatment). Amblyopic eye visual acuity and binocular outcomes (Randot Preschool Stereoacuity, extent of suppression, and depth of suppression) were assessed at baseline and at 2 weeks.ResultsMean amblyopic eye visual acuity (P < 0.001) and mean stereoacuity improved (P = 0.045), and mean extent (P = 0.005) and depth of suppression (P = 0.003) were reduced from baseline at the 2-week visit (87% game adherence, 100% movie adherence). Depth of suppression was reduced more in children aged <8 years than in those aged ≥8 years (P = 0.004). Worse baseline depth of suppression was correlated with a larger depth of suppression reduction at 2 weeks (P = 0.001).ConclusionsAfter 2 weeks, binocular treatment in amblyopic children improved visual acuity and binocular outcomes, reducing the extent and depth of suppression and improving stereoacuity. Binocular treatments that rebalance contrast to overcome suppression are a promising additional option for treating amblyopia.

Stereoacuity Improvement using Random-Dot Video Games

“…The most recent research indicates, however, that dichoptic stimulation is capable of reducing suppression depth and extent and improving binocular vision (restoring simultaneous binocular perception). In some cases, this coincides with improved stereoacuity 14,15 . Some studies have proposed a different intervention approach that is focused on the direct stimulation of stereopsis through perceptual learning activities 16,17 .…”

Classification of visual cortex plasticity phenotypes following treatment for amblyopia

“…We explored BV treatment because it promotes long-lasting recovery of good acuity in both eyes [27] and those findings are similar to promising results of binocular therapies for treating amblyopia in children [65]. Furthermore, there is good physiological recovery with BV [29], [60].…”

Patching and Suppression in Amblyopia: One Mechanism or Two?

“…Subsequent studies have confirmed this relationship Li et al, 2013;Spiegel et al, 2013). This is clear in adults from the aforementioned studies but not so in children (although see Kelly et al, 2018), from whom it is more difficult to obtain valid measurements of interocular suppression.…”

“…It involves re-establishing binocular vision as the first step by using binocularly based training therapy, which relies on a theory that amblyopia and abnormal interocular suppression are causally linked (Baker et al, 2008;Li et al, 2011;Birch, 2013;Ding et al, 2013;Zhou et al, 2013bZhou et al, ,c, 2018. It improves not only binocular vision Hess and Thompson, 2015;Webber et al, 2016;Kelly et al, 2018) but also monocular acuity (Hess et al, 2010bTo et al, 2011;Li et al, 2013Li et al, , 2014Mansouri et al, 2014;Birch et al, 2015). Despite ongoing debate concerning which therapeutic approach is more effective (Holmes et al, 2016;Kelly et al, 2016;Gao et al, 2018;Manh et al, 2018;Pineles et al, 2019), one should bear in mind the possibility that the visual improvements from both approaches might involve the same mechanisms in the brain.…”

“…However, these two therapeutic protocols could involve disparate neural mechanisms as exemplified by their numerous differences. For example, they differ in the following ways: binocular outcomes [occlusionpoor (Birch, 2013); binocular therapy -good Knox et al, 2012;Li et al, 2013;Kelly et al, 2018)], age dependence [occlusion -only children (Epelbaum et al, 1993); binocular therapy -children and adults (Mansouri et al, 2014)], duration dependence [occlusion -120-240 h (Stewart et al, 2007); binocular therapy -20-40 h (Hess et al, 2010b;Mansouri et al, 2014)], and post-therapeutic remission [occlusion -24-27% (Holmes et al, 2004;Bhola et al, 2006); binocular therapyno remission Birch et al, 2015)].…”