Amblyopia

Contrast-rebalanced dichoptic movies have been shown to be an effective binocular treatment for amblyopia in the laboratory. Yet, at-home therapy is a more practical approach. In a randomized clinical trial, we compared dichoptic movies, streamed at-home on a handheld 3D-enabled game console, versus patching as amblyopia treatment. Sixty-five amblyopic children (3-7 years; 20/32-125) were randomly assigned to one of two parallel arms, binocular treatment (3 movies/week) or patching (14 h/week). The primary outcome, change in best corrected visual acuity (BCVA) at the 2-week visit was completed by 28 and 30, respectively. After the primary outcome, both groups of children had the option to complete up to 6 weeks of binocular treatment. At the 2-week primary outcome visit, BCVA had improved in the movie (0.07 ± 0.02 logMAR; p 95%: - 0.02 to 0.04; p = .48). Visual acuity improved in both groups with binocular treatment up to 6 weeks (0.15 and 0.18 logMAR improvement, respectively). This novel, at-home, binocular movie treatment improved amblyopic eye BCVA after 2 weeks (similar to patching), with additional improvement up to 6 weeks. Repeated binocular visual experience with contrast-rebalanced binocular movies provides an additional treatment option for amblyopia.Clincaltrials.gov identifier: NCT03825107 (31/01/2019).

Visual crowding is the disruptive effect of clutter on object recognition. Although most prominent in adult peripheral vision, crowding also disrupts foveal vision in typically developing children and those with strabismic amblyopia. Do these crowding effects share the same mechanism? Here we exploit observations that crowded errors in peripheral vision are not random: Target objects appear either averaged with the flankers (assimilation) or replaced by them (substitution). If amblyopic and developmental crowding share the same mechanism, then their errors should be similarly systematic. We tested foveal vision in children aged 3 to 8 years with typical vision or strabismic amblyopia and peripheral vision in typical adults. The perceptual effects of crowding were measured by requiring observers to adjust a reference stimulus to match the perceived orientation of a target "Vac-Man" element. When the target was surrounded by flankers that differed by ± 30°, all three groups (adults and children with typical or amblyopic vision) reported orientations between the target and flankers (assimilation). Errors were reduced with ± 90° differences but primarily matched the flanker orientation (substitution) when they did occur. A population pooling model of crowding successfully simulated this pattern of errors in all three groups. We conclude that the perceptual effects of amblyopic and developing crowding are systematic and resemble the near periphery in adults, suggesting a common underlying mechanism.

Monocular deprivation early in development causes amblyopia, a severe visual impairment. Prognosis is poor if therapy is initiated after an early critical period. However, clinical observations have shown that recovery from amblyopia can occur later in life when the non-deprived (fellow) eye is removed. The traditional interpretation of this finding is that vision is improved simply by the elimination of interocular suppression in primary visual cortex, revealing responses to previously subthreshold input. However, an alternative explanation is that silencing activity in the fellow eye establishes conditions in visual cortex that enable the weak connections from the amblyopic eye to gain strength, in which case the recovery would persist even if vision is restored in the fellow eye. Consistent with this idea, we show here in cats and mice that temporary inactivation of the fellow eye is sufficient to promote a full and enduring recovery from amblyopia at ages when conventional treatments fail. Thus, connections serving the amblyopic eye are capable of substantial plasticity beyond the critical period, and this potential is unleashed by reversibly silencing the fellow eye.

BackgroundConventional amblyopia treatment involves the occlusion of the fellow eye using an eye patch. However, this approach imposes a substantial psychological and physical burden on pediatric patients with amblyopia, resulting in low adherence and suboptimal visual outcomes. As responsiveness to therapy declines beyond early childhood, treatments that can enhance adherence and improve efficacy are needed. We developed a virtual reality dichoptic training app (VR app) that integrates gamification and hand-eye coordination training in pediatric patients with amblyopia.ObjectiveThis study investigated the effect of a VR app on visual acuity improvement in pediatric patients with amblyopia compared with conventional occlusion therapy using an eye patch.MethodsThis is a multicenter, open-label, prospective, randomized controlled trial that will be conducted at 3 centers in Tokyo, Japan. Pediatric patients aged 3-10 years with anisometropic, strabismic, or refractive amblyopia will be enrolled. Participants will be assigned 1:1 to a VR app group or a control group. The VR app group will use the VR app at home for 1 hour per day for 6 months. The control group will undergo conventional occlusion therapy with an eye patch for 6 months. Each group will comprise 15 participants (30 participants in total). Ophthalmologic examinations will be performed at baseline and at weeks 4, 8, 12, 16, 20, and 24. The primary endpoint will be the change in the best-corrected visual acuity in the amblyopic eye from baseline to week 12. Secondary endpoints will include changes in best-corrected visual acuity, stereopsis, and ocular deviation through week 24. We will also assess treatment adherence, defined as the ratio of the cumulative actual treatment time to the cumulative prescribed time; record adverse events, and evaluate usability in the VR app group. Longitudinal changes in outcome measures will be analyzed using a mixed-effects model.ResultsParticipant enrollment will start from January 1, 2026, to September 30, 2026. The data analysis will begin on October 1, 2026, and the results will be reported by March 31, 2027.ConclusionsThis study will clarify the effectiveness of the newly developed VR app in improving treatment outcomes and adherence among pediatric patients with amblyopia. By addressing the limitations of conventional occlusion therapy and providing a potentially more efficacious and acceptable treatment option, the VR app may enhance clinical outcomes and represent a paradigm shift in the treatment of pediatric amblyopia.