Barriers to successful dichoptic treatment for amblyopia in young children

Effectiveness of optical treatment in amblyopia and validation of measuring spectacle compliance with the ODM

PURPOSE

The improvement in visual acuity (VA) was determined during optical treatment in children with amblyopia before their participation in a randomised clinical trial comparing the effect of dichoptic video gaming using virtual reality goggles with occlusion therapy.

METHODS

Children aged 4-12 years with an interocular VA difference ≥0.20 logMAR and an amblyogenic factor: strabismus <30Δ, ≥1.00 D anisometropia, astigmatism ≥1.50 D and/or hypermetropia ≥1.50 D were eligible for 16 weeks of optical treatment. Children with previous amblyopia treatment were excluded. Compliance with spectacle wear was measured electronically over 1 week using the occlusion dose monitor (ODM). The reliability of these measurements was verified. The main outcome was an increase in amblyopic eye VA from baseline to 16 weeks.

RESULTS

Sixty-five children entered the optical treatment period. Mean age was 6.0 ± 2.2 years (range: 4-12 years; IQR 4.5-6.7 years). Amblyopia was caused by anisometropia in 53 (82%) children, strabismus in 6 (9%) and combined mechanism in 6 (9%). After optical treatment, mean VA improved by 0.20 logMAR (SD 0.28; p < 0.001) and 0.07 in the amblyopic and fellow eye, respectively (SD 0.20; p = 0.03). This resulted in 24 children (37%) with an interocular VA difference <0.20 logMAR and in 17% of children with VA at the start of 0.30 logMAR or worse. Poor VA in the amblyopic eye at baseline (p = 0.001) and high anisometropia (p = 0.001) were associated with VA improvement. On average, spectacles were worn 9.7 ± 2.4 h/day (range: 2.3-13.6 h); mean compliance was 73% ± 18% of estimated wake time. Only ambient temperature ≥ 31°C or when spectacles were worn on top of the head prevented a reliable ODM measurement.

CONCLUSIONS

VA improved by two lines resulting in more than a third of the children being treated sufficiently with spectacles alone and no longer being classified as amblyopic. The ODM proved to be a reliable method of measuring compliance with spectacle wear.

Supervised dichoptic gaming versus monitored occlusion therapy for childhood amblyopia: Effectiveness and efficiency

PURPOSE

To compare the effectiveness and efficiency of supervised dichoptic action-videogame play to occlusion therapy in children with amblyopia.

METHODS

Newly diagnosed children with amblyopia aged 4-12 years were recruited, excluding strabismus >30PD. After 16 weeks of refractive adaptation children were randomized to gaming 1 h/week supervised by the researcher, or electronically monitored occlusion 2 h/day. The gaming group played a dichoptic action-videogame using virtual reality goggles, which included the task of catching a snowflake presented intermittently to the amblyopic eye. Contrast for the fellow eye was self-adjusted until 2 identical images were perceived. The primary outcome was visual acuity (VA) change from baseline to 24 weeks.

RESULTS

We recruited 96 children, 29 declined and 2 were excluded for language or legal issues. After refractive adaptation, 24 of the remaining 65 no longer met the inclusion criteria for amblyopia, and 8 dropped out. Of 16 children treated with gaming, 7 (6.7 years) completed treatment, whereas 9 younger children (5.3 years) did not. Of 17 treated with occlusion, 14 (5.1 years) completed treatment and 3 (4.5 years) did not. Of 5 children with small-angle strabismus, 3 treated with occlusion completed treatment and 2 treated with gaming did not. Median VA improved by 0.30 logMAR (IQR 0.20-0.40) after gaming, 0.20 logMAR (0.00-0.30) after occlusion (p = 0.823). Treatment efficiency was 1.25 logMAR/100 h (range 0.42-2.08) with gaming, 0.08 (-0.19-0.68) with occlusion (p < 0.001).

CONCLUSION

Dichoptic gaming seems a viable alternative for older children with refractive amblyopia after glasses adaptation. Treatment efficiency with gaming under continuous supervision was 15 times higher than with occlusion at home.

Current Developments in the Management of Amblyopia with the Use of Perceptual Learning Techniques

Background and Objectives: Amblyopia is a neurodevelopmental disorder caused by interocular suppression of visual input, affecting visual acuity, stereopsis, contrast sensitivity, and other visual functions. Conventional treatment comprises occlusion of the sound eye. In recent years, novel therapies that deploy perceptual learning (PL) principles have been introduced. The purpose of this study is to assess the latest scientific data on this topic. Materials and Methods: For this purpose, we conducted a literature search for relevant studies published during the previous 4 years (2020-2023). Results: A plethora of visual perceptual learning protocols have been recently developed. Dichoptic video games, contrast rebalanced movies, and online perceptual training platforms are the main formats. Perceptual learning activates neuroplasticity, overcomes interocular suppression, and improves the visual impairments induced by amblyopia. Conclusions: This novel treatment is effective in both children and adults, as well as in patients non-responding to patching.

Effects of virtual reality on the treatment of amblyopia in children: A systematic review and meta-analysis

PROBLEM

Virtual reality technology has been used to treat amblyopia in children. However, it is unclear how virtual reality technology differs from conventional patching therapy in terms of effectiveness.

ELIGIBILITY CRITERIA

Eligible randomized controlled studies were retrieved from PubMed, Embase, Scopus, the Cochrane Library, and Web of Science through February 2023.

SAMPLE

Eight studies included 10 trials with 459 participants were included in the current meta-analysis. Two studies (Herbison et al., 2016; Huang et al., 2022) included two trials each. Thus, a total of ten trials were included in the current meta-analysis.

RESULTS

Overall, virtual reality technology treatment significantly improved visual acuity by 0.07 log MAR (95% confidence interval [CI], -0.11 to -0.02; P < 0.001; I2 = 94.4%) compared with traditional patching therapy. In addition, subgroup analyses also revealed that treatment with virtual reality technology was more effective when the child was younger than seven years old, or when the duration of the intervention was no more than twenty hours.

CONCLUSIONS

Virtual reality technology treatment showed significant effects in improving visual acuity in children who were seven years of age or younger with amblyopia.

IMPLICATIONS

Virtual reality technology treatment is effective in treating amblyopia in children. Virtual reality therapy is also entertaining and popular among children and can be applied to the treatment of amblyopia in children in the future.

Stereoptic serious games as a visual rehabilitation tool for individuals with a residual amblyopia (AMBER trial): a protocol for a crossover randomized controlled trial

BACKGROUND

Amblyopia is the most common developmental vision disorder in children. The initial treatment consists of refractive correction. When insufficient, occlusion therapy may further improve visual acuity. However, the challenges and compliance issues associated with occlusion therapy may result in treatment failure and residual amblyopia. Virtual reality (VR) games developed to improve visual function have shown positive preliminary results. The aim of this study is to determine the efficacy of these games to improve vision, attention, and motor skills in patients with residual amblyopia and identify brain-related changes. We hypothesize that a VR-based training with the suggested ingredients (3D cues and rich feedback), combined with increasing the difficulty level and the use of various games in a home-based environment is crucial for treatment efficacy of vision recovery, and may be particularly effective in children.

METHODS

The AMBER study is a randomized, cross-over, controlled trial designed to assess the effect of binocular stimulation (VR-based stereoptic serious games) in individuals with residual amblyopia (n = 30, 6-35 years of age), compared to refractive correction on vision, selective attention and motor control skills. Additionally, they will be compared to a control group of age-matched healthy individuals (n = 30) to account for the unique benefit of VR-based serious games. All participants will play serious games 30 min per day, 5 days per week, for 8 weeks. The games are delivered with the Vivid Vision Home software. The amblyopic cohort will receive both treatments in a randomized order according to the type of amblyopia, while the control group will only receive the VR-based stereoscopic serious games. The primary outcome is visual acuity in the amblyopic eye. Secondary outcomes include stereoacuity, functional vision, cortical visual responses, selective attention, and motor control. The outcomes will be measured before and after each treatment with 8-week follow-up.

DISCUSSION

The VR-based games used in this study have been conceived to deliver binocular visual stimulation tailored to the individual visual needs of the patient, which will potentially result in improved basic and functional vision skills as well as visual attention and motor control skills.

TRIAL REGISTRATION

This protocol is registered on ClinicalTrials.gov (identifier: NCT05114252) and in the Swiss National Clinical Trials Portal (identifier: SNCTP000005024).

Applications and implications for extended reality to improve binocular vision and stereopsis

Extended reality (XR) devices, including virtual reality (VR), augmented reality (AR), and mixed reality (MR) devices, are immersive technologies that can swap or merge the natural environment with virtual content (e.g., videogames, movies, or other content). Although these devices are widely used for playing videogames and other applications, they have one distinct feature that makes them potentially very useful for the measurement and treatment of binocular vision anomalies-they can deliver different content to the two eyes simultaneously. Indeed, horizontally shifting the images in the two eyes (thereby creating binocular disparity) can provide the user with a compelling percept of depth through stereopsis. Because these devices are stereoscopic, they can also be used as high-tech synoptophores, in which the images to the two eyes differ in contrast, luminance, size, position, and content for measuring and treating binocular anomalies. The inclusion of eye tracking in VR adds an additional dimension to its utility in measuring and treating binocular vision anomalies, as well as other conditions. This paper describes the essential requirements for testing and treating binocular anomalies and reviews current studies in which XR devices have been used to measure and treat binocular vision anomalies.

Learning to see in depth

Stereopsis provides us with a vivid impression of the depth and distance of objects in our 3- dimensional world. Stereopsis is important for a number of everyday visual tasks, including (but not limited to) reaching and grasping, fine visuo-motor control, and navigating in our world. This review briefly discusses the neural substrate for normal binocular vision and stereopsis and its development in primates; outlines some of the issues and limitations of stereopsis tests and examines some of the factors that limit the typical development of stereopsis and the causes and consequences of stereo-deficiency and stereo-blindness. Finally, we review several approaches to improving or recovering stereopsis in both neurotypical individuals and those with stereo-deficiency and stereo-blindness and outline some emerging strategies for improving stereopsis.

Treatment compliance in amblyopia: A mini-review and description of a novel online platform for compliance tracking

Patient compliance with amblyopia therapies, including eye patching and atropine drops, is crucial for optimal visual acuity outcomes. Studies utilizing objective measures of compliance measurement have consistently shown that a majority of patients receive significantly less treatment than prescribed. We review the subjective and objective compliance rates reported in the literature, assess possible explanations for poor compliance and describe studies of interventions to improve compliance. Additionally, we report our experience implementing Inside Out Care, a novel online platform designed to improve monitoring of amblyopia patient compliance, in our clinics. We have found that this platform, which is accessible via both computer and smartphone, has improved monitoring of amblyopia patient patching compliance, as well as allowed for enhanced doctor-patient communication.

Evaluation of the Efficacy of a New Dichoptic Digital Platform to Treat the Anisometropic and Isometropic Amblyopia

The aim of the current study was to evaluate the results of a novel dichoptic training program using an online platform in a group of subjects with refractive amblyopia, performing a comparative analysis of unilateral and bilateral amblyopic cases. For this purpose, a retrospective study analysis of data of 161 children (4−13 years) who underwent dichoptic treatment with the Bynocs® platform (Kanohi Eye Pvt. Ltd., Mumbai, India) was performed. In all cases, the therapy protocol consisted of sessions of training of 30 min daily 5 times a week for 6 weeks. Best corrected visual acuity (BCVA) in the non-dominant eye improved significantly with the treatment, with a mean change of 0.39 logMAR in the whole sample (p < 0.001). Regarding binocularity, the binocular function (BF) score also experienced a significant improvement (p < 0.001), with a mean change of 1.55 with therapy in the whole sample. The BCVA of the dominant eye only improved significantly (p < 0.001) in the isometropic amblyopic subgroup. In conclusion, the use of the dichoptic therapy with the digital platform evaluated allows an effective restoration of visual acuity and binocular function in children with anisometropic and isometropic amblyopia.

A Randomized Trial of Binocular Dig Rush Game Treatment for Amblyopia in Children Aged 4 to 6 Years

SIGNIFICANCE

Binocular treatment for unilateral amblyopia is an emerging treatment that requires evaluation through a randomized clinical trial.

PURPOSE

This study aimed to compare change in amblyopic-eye visual acuity (VA) in children aged 4 to 6 years treated with the dichoptic binocular iPad (Apple, Cupertino, CA) game, Dig Rush (not yet commercially available; Ubisoft, Montreal, Canada), plus continued spectacle correction versus continued spectacle correction alone.

METHODS

Children (mean age, 5.7 years) were randomly assigned to home treatment for 8 weeks with the iPad game (prescribed 1 h/d, 5 d/wk [n = 92], or continued spectacle correction alone [n = 90]) in a multicenter randomized clinical trial. Before enrollment, children wearing spectacles were required to have at least 16 weeks of wear or no improvement in amblyopic-eye VA (<0.1 logMAR) for at least 8 weeks. Outcome was change in amblyopic-eye VA from baseline to 4 weeks (primary) and 8 weeks (secondary) assessed by masked examiner.

RESULTS

A total of 182 children with anisometropic (63%), strabismic (16%; <5∆ near, simultaneous prism and cover test), or combined-mechanism (20%) amblyopia (20/40 to 20/200; mean, 20/63) were enrolled. After 4 weeks, mean amblyopic VA improved by 1.1 logMAR lines with binocular treatment and 0.6 logMAR lines with spectacles alone (adjusted difference, 0.5 lines; 95.1% confidence interval [CI], 0.1 to 0.9). After 8 weeks, results (binocular treatment: mean amblyopic-eye VA improvement, 1.3 vs. 1.0 logMAR lines with spectacles alone; adjusted difference, 0.3 lines; 98.4% CI, -0.2 to 0.8 lines) were inconclusive because the CI included both zero and the pre-defined difference in mean VA change of 0.75 logMAR lines.

CONCLUSIONS

In 4- to 6-year-old children with amblyopia, binocular Dig Rush treatment resulted in greater improvement in amblyopic-eye VA for 4 weeks but not 8 weeks. Future work is required to determine if modifications to the contrast increment algorithm or other aspects of the game or its implementation could enhance the treatment effect.