Binocular iPad Game vs Patching for Treatment of Amblyopia in Children: A Randomized Clinical Trial

Leveraging neural plasticity for the treatment of amblyopia

Amblyopia is a form of visual cortical impairment that arises from abnormal visual experience early in life. Most often, amblyopia is a unilateral visual impairment that can develop as a result of strabismus, anisometropia, or a combination of these conditions that result in discordant binocular experience. Characterized by reduced visual acuity and impaired binocular function, amblyopia places a substantial burden on the developing child. Although frontline treatment with glasses and patching can improve visual acuity, residual amblyopia remains for most children. Newer binocular-based therapies can elicit rapid recovery of visual acuity and may also improve stereoacuity in some children. Nevertheless, for both treatment modalities full recovery is elusive, recurrence of amblyopia is common, and improvements are negligible when treatment is administered at older ages. Insights derived from animal models about the factors that govern neural plasticity have been leveraged to develop innovative treatments for amblyopia. These novel therapies exhibit efficacy to promote recovery, and some are effective even at ages when conventional treatments fail to yield benefit. Approaches for enhancing visual system plasticity and promoting recovery from amblyopia include altering the balance between excitatory and inhibitory mechanisms, reversing the accumulation of proteins that inhibit plasticity, and harnessing the principles of metaplasticity. Although these therapies have exhibited promising results in animal models, their safety and ability to remediate amblyopia need to be evaluated in humans.

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.

Randomized Controlled Trial of Patching versus Dichoptic Stimulation Using Virtual Reality for Amblyopia Therapy

Purpose: To compare the outcomes of patching to dichoptic stimulation using virtual reality (VR) in moderate and severe amblyopia.Methods: This study was conducted on 86 subjects with unilateral anisometropic and mixed amblyopia. The subjects were randomized to the VR or patching group. The VR group received treatment using the Vivid Vision software (Vivid Vision Inc., San Francisco, USA) with each subject receiving weekly 2 h-sessions for 10 weeks. The patching group was prescribed patching for 10 weeks. Best-corrected visual acuity (BCVA) was measured using a single crowded letter in an ETDRS chart before, after 10 weeks of treatment, and after another 10 weeks of cessation of treatment. Near stereoacuity was measured using the TNO test.Results: Forty-two patients were randomized to the patching group and 44 to the VR group. The median age of the subjects was 12.0 (range 6.0 to 37.0) years. In the VR group, mean amblyopic eye BCVA showed statistically significant improvement by 0.89 line (95% confidence interval {CI}, 0.73 to 1.35 lines; p < 0.001) after 10 weeks of therapy, and after another 10 weeks of follow-up by 1.32 lines from baseline (95% CI, 1.15 to 1.7 lines; p < 0.001). Regarding the patching group, mean BCVA showed statistically significant improvement after 10 weeks by 1.38 lines (95% CI, 0.82 to 1.8 lines; p < 0.001), and after another 10 weeks by 1 line from baseline (95% CI, 0.06-0.147; 0.6 to 1.47 lines; p < 0.001). There was no significant difference between both groups at any time-point (p values >0.05). No serious adverse events were noted. Adults and severe amblyopes in the VR group showed more significant VA improvement than their counterparts in the patching group.Conclusions: Amblyopes treated using VR dichoptic treatment demonstrated statistically significant VA improvement after 10 and 20 weeks of follow-up that is comparable to patching.

Effectiveness of a Novel Video Game Platform in the Treatment of Pediatric Amblyopia

PURPOSE

To test the non-inferiority of a novel game platform for the treatment of pediatric amblyopia compared to standard eye patching.

METHODS

Forty participants (ages 4 to 18 years) across seven optometric clinics in the United States diagnosed as having amblyopia associated with anisometropia were randomly assigned to either 12 weeks of eye patching therapy (n = 19) or Barron Vision (Barron Associates, Inc) video game treatment (n = 21). Participants in the eye patching group with best corrected visual acuity (BCVA) worse than 20/200 in their amblyopic eye were prescribed 6 hours of patching daily, whereas those whose BCVA was 20/200 (1.00 logarithm of the minimum angle of resolution [logMAR]) or better were instructed to patch for 2 hours daily. Participants in the video game group, irrespective of the severity of their amblyopia, were instructed to play four different 5-minute mini-games five times a week for a total of 20 minutes a day.

RESULTS

A mixed linear modeling analysis of before and after BCVA differences after 12 weeks showed the non-inferiority of video game treatment to eye patching using a 0.10 logMAR threshold while adjusting for the participant's age, sex, and baseline BCVA.

CONCLUSIONS

The results of the study suggest that a 12-week home-based video game vision therapy intervention can provide equivalent treatment outcomes to eye patching for amblyopia in children ages 5 to 18 years. Video game-based vision therapy may be a more acceptable and time-efficient alternative to existing approaches. By incorporating elements of perceptual learning, approaches such as Barron Vision video game treatment may have additional long-term therapeutic benefits and may improve treatment compliance. [J Pediatr Ophthalmol Strabismus. 2024;61(1):20-29.].

The Effect of Web-Based Telerehabilitation Programs on Children and Adolescents With Brain Injury: Systematic Review and Meta-Analysis

BACKGROUND

Acquired brain injury (ABI) in children and adolescents can lead to motor and executive impairments that often require long-term treatment. The implementation of web-based telerehabilitation therapy at home is a method to improve the functional status of patients. Therefore, we performed a systematic review of the effects of web-based telerehabilitation programs on functional outcomes in children and adolescents with brain injury and supplemented the findings with a meta-analysis.

OBJECTIVE

This study evaluated the therapeutic effect of web-based telerehabilitation training on children and adolescents with brain injury to determine whether web-based telerehabilitation therapy improved motor function, executive function, physical activity level, lower limb strength, hand and upper limb function, visual processing skills, and occupational functional performance in children and adolescents with brain injury.

METHODS

PubMed, Embase, Scopus, Web of Science, and the Cochrane Library were searched for randomized controlled trials on web-based telerehabilitation programs in children and adolescents with brain injury until December 2022, and the risk of bias was evaluated using the Cochrane Collaboration Tool. Relevant data were extracted, and a meta-analysis was performed using RevMan5.3 software.

RESULTS

Overall, 17 studies involving 848 patients were included. Web-based telerehabilitation therapy improved the motor function (standardized mean difference [SMD] 0.29, 95% CI 0.01-0.57; P=.04), physical activity level (SMD 0.42, 95% CI 0.11-0.73; P=.007), lower limb strength (SMD 0.52, 95% CI 0.13-0.90; P=.009), and visual processing skills (SMD 0.26, 95% CI 0.02-0.50; P=.04) of children and adolescents with brain injury. It also improved executive function in letter-number sequencing (SMD 1.26, 95% CI 0.26-2.26; P=.01), attention (SMD 0.38, 95% CI 0.09-0.66; P=.009), and symbol search (SMD 1.18, 95% CI 0.43-1.93, P=.002).

CONCLUSIONS

Web-based telerehabilitation therapy improved motor function, physical activity level, lower limb strength, letter-number sequencing, attention, and symbol search, which improved the quality of life in children and adolescents with brain injury. Web-based telerehabilitation programs provide great convenience for children and adolescents with ABI who need long-term treatment and allow them to exercise at home for rehabilitation training. The widespread implementation of remote interventions also provides children and adolescents in remote areas with better access to rehabilitation services. This review provides evidence for the effectiveness of web-based telerehabilitation therapy, but there was heterogeneity in some of the results because of different disease types and intervention programs. Future studies can expand the sample size according to disease type and increase follow-up time according to different exercise prescriptions to further refine the long-term effects of this intervention on various functions of children and adolescents with ABI.

TRIAL REGISTRATION

PROSPERO CRD42023421917; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=421917.

Digital Therapy for Visual Acuity and Binocular Function in Children with Anisometropic Amblyopia

Amblyopia affects development of children's monocular vision and binocular function and becomes a largely intractable problem with increasing aging. This study is to investigate the binocular function and evaluate efficacy of digital therapy in children 8-13 years of age with anisometropic amblyopia. The patients in the digital therapy group performed the training with the digital amblyopia therapeutic software. The visual acuity and binocular function (perceptual eye position [PEP], suppression, and stereopsis) were examined at the first visit and 3-month post-treatment. Twenty-three cases in the control group and 25 cases in the digital therapy group were enrolled. The results revealed that 3-month digital therapy can effectively improve corrected distance visual acuity (CDVA) and improve the binocular function, including PEP, suppression, and second-order stereopsis in children with anisometropic amblyopia, 8-13 years of age. Digital therapy for amblyopia can effectively improve monocular CDVA of amblyopic eyes and binocular function in older children with anisometropic amblyopia.

Computer-Assisted Visual Training in Children and Adolescents with Developmental Visual Disorders

BACKGROUND

In this systematic review, we address the question whether children and adolescents with developmental visual disorders benefit from computer-assisted visual training.

METHODS

Systematic literature searches were carried out in three bibliographic databases (initial search in October 2021) and trial registries. Included were randomized controlled trials that evaluated the efficacy of computer-assisted visual training in children and adolescents with developmental visual disorders in comparison to no training, sham training, or conservative treatment.

RESULTS

The inclusion criteria were met by 17 trials (with a total of 1323 children and adolescents) focusing on binocular or monocular computer-assisted visual training for the treatment of amblyopia. In these trials, visual training was carried out for 2 to 24 weeks, either as "stand alone" therapy or in addition to occlusion therapy. Six trials showed a statistically significant difference in favor of the visual training for the outcome "best corrected visual acuity of the amblyopic eye." However, this difference was small and mostly below the threshold of clinical relevance of -0.05 logMAR (equivalent to an improvement of 0.5 lines on the eye chart, or 2.5 letters per line). Only few data were available for the outcomes "binocular vision" and "adverse events"; the differences between the groups were similarly small.

CONCLUSION

The currently available data do not permit any firm conclusions regarding the efficacy of visual training in children and adolescents with amblyopia. Moreover, treatment adherence was often insufficient and the treatment durations in the trials was relatively short. No results from randomized trials have yet been published with respect to other developmental visual disorders (refractive errors, strabismus).

A Prospective Trial to Assess the Efficacy of Eye-Tracking-Based Binocular Treatment versus Patching for Children's Amblyopia: A Pilot Study

PURPOSE

To assess visual acuity (VA) and stereoacuity (SA) improvements in children with amblyopia treated with either binocular dichoptic treatment or patching treatment.

METHODS

In this pilot prospective coherent study, 34 participants between 4 and 9 years of age with unilateral anisometropic amblyopia and without history of prior amblyopia treatment were enrolled into three groups. Full treatment group (FTG; n = 12): participants were prescribed the binocular dichoptic treatment to watch for 90 minutes per day, 5 days a week. Part-time treatment group (PTTG; n = 8): participants were prescribed the same binocular treatment as FTG, 90 minutes per day, 3 days per week. Patching treatment group (PTG; n = 14): participants wore an adhesive patch over the dominant eye for 2 hours per day, 7 days per week. Amblyopic-eye distance visual acuity (DVA), near visual acuity (NVA) and SA were evaluated at baseline, 4, 8, and 12 weeks.

RESULTS

At 12 weeks, mean amblyopic-eye DVA improved 1.8 lines (95% CI, 1.1-2.5) in FTG, 1.5 lines (95% CI, 0.4-2.7) in PTTG and 3.0 lines (95% CI, 2.0-4.0) in PTG. The amblyopic-eye NVA improved 2.9 lines (95% CI, 2.4-3.5) in FTG, 1.7 lines (95% CI, 0.5-3.0) in PTTG and 2.8 lines (95% CI, 1.8-3.9) in PTG. The SA improved 0.38 log-arcseconds (95% CI, 0.24-0.53) in FTG, 0.59 log-arcseconds (95% CI, 0.36-0.82) in PTTG and 0.40 log-arcseconds (95% CI, 0.13-0.67) in PTG. No significant differences were found in DVA, NVA or SA improvement between FTG and PTG at 12 weeks.

CONCLUSIONS

VA and SA after binocular dichoptic treatment produced a similar therapeutic outcome to patching, suggesting a potential value for binocular therapy when treating anisometropic moderate degree of Children's amblyopia.

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.

Harnessing brain plasticity to improve binocular vision in amblyopia: An evidence-based update

Amblyopia is a developmental visual disorder resulting from atypical binocular experience in early childhood that leads to abnormal visual cortex development and vision impairment. Recovery from amblyopia requires significant visual cortex neuroplasticity, i.e. the ability of the central nervous system and its synaptic connections to adapt their structure and function. There is a high level of neuroplasticity in early development and, historically, neuroplastic responses to changes in visual experience were thought to be restricted to a "critical period" in early life. However, as our review now shows, the evidence is growing that plasticity of the adult visual system can also be harnessed to improve vision in amblyopia. Amblyopia treatment involves correcting refractive error to ensure clear and equal retinal image formation in both eyes, then, if necessary, promoting the use of the amblyopic eye by hindering or reducing visual input from the better eye through patching or pharmacologic therapy. Early treatment in children can lead to visual acuity gains and the development of binocular vision in some cases; however, many children do not respond to treatment, and many adults with amblyopia have historically been untreated or undertreated. Here we review the current evidence on how dichoptic training can be used as a novel binocular therapeutic approach to facilitate visual processing of input from the amblyopic eye and can simultaneously engage both eyes in a training task that requires binocular integration. It is a novel and promising treatment for amblyopia in both children and adults.

Anisometropic amblyopia: A review of functional and structural changes and treatment

Amblyopia is the decreased best-corrected visual acuity (BCVA) in one or both eyes caused by the abnormal processing of visual input during development. One common cause of amblyopia is anisometropia, which has attracted widespread attention. Many structural changes occur in the primary and extrastriate visual areas of the cerebral cortex, as well as in the eyes, in patients with anisometropic amblyopia. Understanding these mechanisms has provided a favorable theoretical basis for treating anisometropic amblyopia. This article reviews the functional and anatomical changes and progress toward the treatment of anisometropic amblyopia.

Characterizing amblyopic perception under non-rivalrous viewing conditions

Current assessments of interocular interactions in amblyopia often use rivalrous stimuli, with conflicting stimuli in each eye, which does not reflect vision under typical circumstances. Here we measure interocular interactions in observers with amblyopia, strabismus with equal vision, and controls using a non-rivalrous stimulus. Observers used a joystick to continuously report the perceived binocular contrast of dichoptic grating stimuli, identical except that the stimulus was contrast-modulated independently in each eye over time. Consistent with previous studies, a model predicting the time-course of perceived contrast found increased amblyopic eye attenuation, and reduced contrast normalization of the fellow eye by the amblyopic eye, in amblyopic participants compared to controls. However, these suppressive interocular effects were weaker than those found in previous studies, suggesting that rivalrous stimuli may overestimate the effects of amblyopia on interocular interactions during naturalistic viewing conditions.

Binocular vision therapy for the treatment of Amblyopia-A review

Amblyopia is a monocular or binocular reduction in visual acuity that results from prolonged visual deprivation in the early years of life. It is second only to refractive error as a cause of poor vision in children. The gold standard treatment of amblyopia includes patching and, less commonly, atropine penalization and filters. These therapies are aimed at improvements in the visual acuity of the amblyopic eye alone. They have compliance and psychosocial issues and gains are accrued after prolonged periods. Experimental studies have demonstrated the presence of binocular cortical communication even in amblyopes and neural plasticity in late childhood as well as adulthood. On this basis, binocular vision therapy aimed at the stimulation of both eyes rather than forced use of the amblyopic eye was developed. Such therapies involve visual tasks designed in such a way that they can be completed only by binocular viewing. These tasks vary from simple game play using red-green glasses, to engaging 3D games and movie viewing. Preliminary data suggest that binocular vision therapy has led to lasting improvements in visual acuity and can be a useful adjunct, if not replacement, to the conventional treatment of amblyopia. In this article, we aim to describe the various binocular vision therapies and review the available literature on the same.

Enriched binocular experience followed by sleep optimally restores binocular visual cortical responses in a mouse model of amblyopia

Studies of primary visual cortex have furthered our understanding of amblyopia, long-lasting visual impairment caused by imbalanced input from the two eyes during childhood, which is commonly treated by patching the dominant eye. However, the relative impacts of monocular vs. binocular visual experiences on recovery from amblyopia are unclear. Moreover, while sleep promotes visual cortex plasticity following loss of input from one eye, its role in recovering binocular visual function is unknown. Using monocular deprivation in juvenile male mice to model amblyopia, we compared recovery of cortical neurons' visual responses after identical-duration, identical-quality binocular or monocular visual experiences. We demonstrate that binocular experience is quantitatively superior in restoring binocular responses in visual cortex neurons. However, this recovery was seen only in freely-sleeping mice; post-experience sleep deprivation prevented functional recovery. Thus, both binocular visual experience and subsequent sleep help to optimally renormalize bV1 responses in a mouse model of amblyopia.

Effectiveness of binocular therapy as a complementary treatment of part-time patching in older amblyopic children: a randomized clinical trial

PURPOSE

To assess the effectiveness of combined use of stereoscopic 3D video movies and part-time patching in treating older amblyopic children with poor response or compliance to traditional patching treatments and comparing this combined treatment with patching alone.

METHODS

Thirty-two children aged 5-12 years with amblyopia associated with anisometropia, strabismus, or both were recruited in a randomized clinical trial. Eligible participants were assigned randomly to the combined and patching groups. Here, binocular treatment refers to using the Bangerter filter to blur the fellow eye and subsequently watching a close-up 3D movie with large parallax. The primary outcome was amblyopic eye (AE) best-corrected visual acuity (BCVA) improvement at six weeks. In addition, secondary outcomes included BCVA of AE improvement at three weeks and change of stereoacuity.

RESULTS

Of 32 participants, mean (SD) age was 6.63 (1.46) years, and 19 (59%) were female. At 6 weeks, mean (SD) amblyopic eye VA improved by 0.17 ± 0.08 logMAR (2-sided 95% CI, 0.13 to 0.22; F = 57.2, p < 0.01) and 0.05 ± 0.04 logMAR (2-sided 95% CI, 0.05 to 0.09; F = 8.73, p = 0.01) in the combined and patching groups, respectively. The difference was statistically significant (mean difference, 0.13 logMAR [1.3 line]; 95% CI, 0.08-0.17 logMAR [0.8-1.7 lines]; t25 = 5.65, p < 0 .01). After treatment, only the combined group had significantly improved stereoacuity, such as binocular function score (median [interquartile range], 2.30 [2.23 to 2.68] vs. 1.69 [1.60 to 2.30] log arcsec; paired, z = -3.53, p < 0.01), and mean stereoacuity gain was 0.47 log arcsec (± 0.22). Changes in other types of stereoacuity were similar.

CONCLUSION

Our laboratory-based binocular treatment strategy engaged a high level of compliance that led to a substantial gain in visual function after a short period of treatment for older amblyopic children having poor response or compliance to traditional patching treatments. Notably, the improving stereoacuity showed a greater advantage.

An Eye-Tracking-Based Dichoptic Home Treatment for Amblyopia: A Multicenter Randomized Clinical Trial

PURPOSE

Comparing visual outcomes after use of a novel binocular eye-tracking-based home treatment (CureSight; NovaSight, Ltd) with patching.

DESIGN

Prospective, multicenter, randomized, masked, controlled, noninferiority pivotal trial.

PARTICIPANTS

One hundred three children 4 to < 9 years with anisometropic, small-angle strabismic or mixed-mechanism amblyopia were randomized 1:1 to either CureSight treatment or patching.

METHODS

The CureSight treatment uses combined anaglyph glasses and an eye tracker to induce real-time blur around the fellow eye fovea in dichoptic streamed video content. Participants used the device for 90 minutes/day, 5 days/week for 16 weeks (120 hours). The patching group received 2 hours of patching 7 days/week (224 hours). The prespecified noninferiority margin was 1 line.

MAIN OUTCOME MEASURES

The primary outcome was the improvement in the amblyopic eye visual acuity (VA), modeled with a repeated measures analysis of covariance. Secondary outcomes included stereoacuity, binocular VA, and treatment adherence rates, analyzed by a 1-sample Wilcoxon test within each group and a 2-sample Wilcoxon test comparing groups. Safety outcomes included the frequency and severity of study-related adverse events (AEs).

RESULTS

CureSight group VA improvement was found to be noninferior to patching group improvement (0.28 ± 0.13 logarithm of the minimum angle of resolution [logMAR] [P < 0.0001] and 0.23 ± 0.14 logMAR [P < 0.0001], respectively; 90% confidence interval [CI] of difference, -0.008 to 0.076). Stereoacuity improvement of 0.40 log arcseconds (P < 0.0001) and improved binocular VA (0.13 logMAR; P < 0.0001) were observed in the binocular treatment group, with similar improvements in the patching group in stereoacuity (0.40 log arcseconds; P < 0.0001) and binocular VA (0.09 logMAR; P < 0.0001), with no significant difference between improvements in the 2 groups in either stereoacuity (difference, 0; 95% CI, -0.27 to -0.27; P = 0.76) or binocular VA (difference, 0.041; 95% CI, -0.002 to 0.085; P = 0.07). The binocular treatment group had a significantly higher adherence than the patching group (91% vs. 83%; 95% CI, -4.0% to 21%; P = 0.011). No serious AEs were found.

CONCLUSIONS

Binocular treatment was well tolerated and noninferior to patching in amblyopic children 4 to < 9 years of age. High adherence may provide an alternative treatment option for amblyopia.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Amblyopia and the whole child

Amblyopia is a disorder of neurodevelopment that occurs when there is discordant binocular visual experience during the first years of life. While treatments are effective in improving visual acuity, there are significant individual differences in response to treatment that cannot be attributed solely to difference in adherence. In this considerable variability in response to treatment, we argue that treatment outcomes might be optimized by utilizing deep phenotyping of amblyopic deficits to guide alternative treatment choices. In addition, an understanding of the broader knock-on effects of amblyopia on developing visually-guided skills, self-perception, and quality of life will facilitate a whole person healthcare approach to amblyopia.

Binocular amblyopia treatment improves manual dexterity

PURPOSE

To determine whether deficits in manual dexterity in children with amblyopia improve after binocular amblyopia treatment and whether improvements are related to age at treatment, baseline sensory status, or amount of improvement in sensory status with treatment.

METHODS

Manual dexterity (Movement Assessment Battery for Children-2), visual acuity, fusion, suppression, and stereoacuity were measured at baseline and after 4-8 weeks of binocular amblyopia in 134 children with amblyopia, including 75 children in the "younger group" (aged 3 to <7 years) and 59 in the "older group" (aged 7-10 years), and in 40 age-similar control children.

RESULTS

Baseline manual dexterity standard scores of amblyopic children were significantly below those of controls in both the younger (8.81 ± 0.33 vs 11.80 ± 0.60 [P < 0.0001]) and older groups (7.19 ± 0.34 vs 9.75 ± 0.57 [P = 0.00013]). After 4-8 weeks of binocular amblyopia treatment, the younger group standard score improved to 9.85 ± 0.35 and the older group improved to 8.08 ± 0.39, but both groups remained significantly lower than controls (P = 0.03 and P = 0.01, resp.). Improvement in manual dexterity standard score was not associated with any baseline factors but was weakly correlated with the amount of visual acuity improvement (rs = 0.26; 95% CI, 0.09-0.41) CONCLUSIONS: Manual dexterity impairments are common among children with amblyopia. In our study cohort, binocular amblyopia treatment improved visual acuity and manual dexterity.

Amblyopia: A review of unmet needs, current treatment options, and emerging therapies

Amblyopia is a global public health issue with extensive, multifaceted impacts on vision and quality of life (QoL) for both patients and families. Geographical variation exists in the management of amblyopia, with traditional mainstay treatments, optical correction, and fellow eye occlusion most successful when implemented at an early age. In recent years, however, studies demonstrating meaningful improvements in older children and adults have challenged the concept of a complete loss of visual processing plasticity beyond the critical period of visual development, with growing evidence supporting the potential efficacy of emerging, more engaging, binocular therapies in both adults and children. Binocular approaches aim to restore deficits in amblyopia that extend beyond monocular visual acuity impairment, including binocular fusion and visuomotor skills. In view of this, incorporating outcome measures that evaluate the visual performance and functional ability of individuals with amblyopia will provide a clearer understanding of the effect of amblyopia on QoL and a more comprehensive evaluation of amblyopia therapies.

Comparison of compliance among patients with pediatric amblyopia undergoing virtual reality-based and traditional patching method training

Introduction

This study aimed to compare compliance between pediatric patients with amblyopia undergoing a smartphone virtual reality-based training method (EYEBIT) and those receiving traditional patching method training.

Methods

A crossover design was adopted in this study. The enrolled children (n = 76) were randomized into the traditional patching and EYEBIT training method groups. The patients received training methods once a day for 2 h and 1 h in the patching and EYEBIT groups, respectively. Follow-up assessments involved interviews with parents regarding children's compliance and questionnaire-based interviews with children; compliance rating was compared between the methods.

Results

All children completed the training and follow-up assessments. There were significant differences in parent and children compliance-related behavior and attitudes between the two training methods (p < 0.05). The EYEBIT method was associated with better compliance than the traditional patching method. Significant correlations were observed among compliance components in both methods. In the correlation analysis between the two groups, the research results showed that in the EYEBIT group, the correlation between children's compliance behaviors and children's compliance attitudes, the correlation between children's compliance behaviors and parents' compliance behaviors, and the correlations between children's compliance attitudes and parents' compliance attitudes were all negatively correlated, and in the traditional patching group, the above three correlation analysis results were all positive.

Conclusion

The use of the EYEBIT method may improve compliance in children with amblyopia; this method appears acceptable to the parents of children with amblyopia.

Comparison of Amblyopia Treatment Effect with Dichoptic Method Using Polarizing Film and Occlusion Therapy Using an Eye Patch

We developed a novel, low-cost, easily administered method that uses a polarizing film to enable dichoptic treatment for amblyopia. In this study, we compared its effects with occlusion therapy using an eye patch. Fifty-eight patients (aged 4.7 ± 1.0 years) diagnosed with anisometric amblyopia were included and instructed to wear complete refractive correction glasses with either occlusion therapy using an eye patch (eye patch group) or dichoptic treatment using polarizing film (polarizing film group) for 2 h per day. We examined the improvement in the visual acuity and compliance rate of the patients 2 months after treatment initiation. After treatment, the polarizing film group showed significant improvement in visual acuity compared with the eye patch group. Moreover, the compliance rate was significantly better in the polarizing film group than in the eye patch group. In both groups, there was a significant correlation between the improvement in visual acuity and compliance rate. This new dichoptic treatment using a polarizing film was shown to be effective for anisometropic amblyopia.

Issues Revisited: Shifts in Binocular Balance Depend on the Deprivation Duration in Normal and Amblyopic Adults

INTRODUCTION

Recent studies indicate that short-term monocular deprivation increases the deprived eye's contribution to binocular fusion in both adults with normal vision and amblyopia. In this study, we investigated whether the changes in visual plasticity depended on the duration of deprivation in normal and amblyopic adults.

METHODS

Twelve anisometropia amblyopic observers (aged 24.8 ± 2.3 years) and 12 age-matched normal observers (aged 23.9 ± 1.2 years) participated in the study. The non-dominant eye of normal observers or amblyopic eye of amblyopic observers was deprived for 30, 120, and 300 min in a randomized order. Their eye balance was measured with a phase combination task, which is a psychophysical test, before and after the deprivation. This design enabled us to measure changes induced in binocular balance as an index visual plasticity due to monocular deprivations.

RESULTS

By comparing the ocular dominance changes as a result of monocular deprivation with different deprivation durations, we found evidence that the ocular dominance changes are slightly larger after longer deprivations in both normal and amblyopic observers, albeit with a statistical significance. The changes from 120-min were significantly greater than those from 30-min deprivation in both groups. The magnitude of changes in sensory eye balance was significantly larger in normal observers than that in the amblyopic observers; however, the longevity of changes in visual plasticity was found to be more long-lasting in amblyopic observers than the normal counterparts.

CONCLUSIONS

The duration of deprivation matters in both normal and amblyopic observers. Ocular dominance imbalance that is typically observed in amblyopia can be more ameliorated with a longer duration of deprivation.

Binocular treatment for individual with amblyopia: A systematic review and meta-analysis

OBJECTIVE

To assess the efficacy of binocular treatment for individual with amblyopia.

METHODS

In this meta-analysis, a comprehensive search of literatures was performed from PubMed, Embase, Cochrane Library and Web of Science databases up to December 21, 2020. Sensitivity analysis was performed for all outcomes. The Begg's test was used to assess the publication bias. Heterogeneity test was conducted for each effect indicator. Indicators were analyzed by random-effects model when the heterogeneity statistic I2 ≥ 50%, on the contrary, indicators were analyzed by fixed-effect model. Standard mean difference (SMD) or weighted mean difference (WMD) was adopted as effect indicators, and the effect amount was expressed as 95% confidence intervals (CIs).

RESULTS

A total of 13 literatures including 1146 participants were finally enrolled, with 595 in the intervention group and 551 in the control group. The results indicated that the improvement of amblyopic eye visual acuity [SMD: 0.882, 95%CI: (0.152, 1.613), P = 0.018] in binocular treatment group was better than that in control group. And binocular treatment could improve stereo acuity in individual with amblyopia [WMD: 0.138, 95%CI: (0.068, 0.208), P < 0.001].

CONCLUSION

Binocular treatment may be beneficial to visual acuity, stereo acuity and binocular function improvement for individual with amblyopia. In clinical practice, binocular treatment can be used as one of the treatments for individual with amblyopia.

Fixation instability, astigmatism, and lack of stereopsis as factors impeding recovery of binocular balance in amblyopia following binocular therapy

Dichoptic therapy is a promising method for improving vision in pediatric and adult patients with amblyopia. However, a systematic understanding about changes in specific visual functions and substantial variation of effect among patients is lacking. Utilizing a novel stereoscopic augmented-reality based training program, 24 pediatric and 18 adult patients were trained for 20 h along a three-month time course with a one-month post-training follow-up for pediatric patients. Changes in stereopsis, distance and near visual acuity, and contrast sensitivity for amblyopic and fellow eyes were measured, and interocular differences were analyzed. To reveal what contributes to successful dichoptic therapy, ANCOVA models were used to analyze progress, considering clinical baseline parameters as covariates that are potential requirements for amblyopic recovery. Significant and lasting improvements have been achieved in stereoacuity, interocular near visual acuity, and interocular contrast sensitivity. Importantly, astigmatism, fixation instability, and lack of stereopsis were major limiting factors for visual acuity, stereoacuity, and contrast sensitivity recovery, respectively. The results demonstrate the feasibility of treatment-efficacy prediction in certain aspects of dichoptic amblyopia therapy. Furthermore, our findings may aid in developing personalized therapeutic protocols, capable of considering individual clinical status, to help clinicians in tailoring therapy to patient profiles for better outcome.

Perceptual learning with dichoptic attention tasks improves attentional modulation in V1 and IPS and reduces interocular suppression in human amblyopia

Long-term and chronic visual suppression to the non-preferred eye in early childhood is a key factor in developing amblyopia, as well as a critical barrier to treat amblyopia. To explore the relationship between selective visual attention and amblyopic suppression and its role in the success of amblyopic training, we used EEG source-imaging to show that training human adults with strabismic and anisometropic amblyopia with dichoptic attention tasks improved attentional modulation of neural populations in the primary visual cortex (V1) and intraparietal sulcus (IPS). We also used psychophysics to show that training reduced interocular suppression along with visual acuity and stereoacuity improvements. Importantly, our results revealed that the reduction of interocular suppression by training was significantly correlated with the improvement of selective visual attention in both training-related and -unrelated tasks in the amblyopic eye, relative to the fellow eye. These findings suggest a relation between interocular suppression and selective visual attention bias between eyes in amblyopic vision, and that dichoptic training with high-attention demand tasks in the amblyopic eye might be an effective way to treat amblyopia.

Phase 2a randomised controlled feasibility trial of a new 'balanced binocular viewing' treatment for unilateral amblyopia in children age 3-8 years: trial protocol

INTRODUCTION

Treatments for amblyopia, the most common vision deficit in children, often have suboptimal results. Occlusion/atropine blurring are fraught with poor adherence, regression and recurrence. These interventions target only the amblyopic eye, failing to address imbalances of cortical input from the two eyes ('suppression'). Dichoptic treatments manipulate binocular visual experience to rebalance input. Poor adherence in early trials of dichoptic therapies inspired our development of balanced binocular viewing (BBV), using movies as child-friendly viewable content. Small observational studies indicate good adherence and efficacy. A feasibility trial is needed to further test safety and gather information to design a full trial.

METHODS/ANALYSIS

We will carry out an observer-masked parallel-group phase 2a feasibility randomised controlled trial at two sites, randomising 44 children aged 3-8 years with unilateral amblyopia to either BBV or standard occlusion/atropine blurring, with 1:1 allocation ratio. We will assess visual function at baseline, 8 and 16 weeks. The primary outcome is intervention safety at 16 weeks, measured as change in interocular suppression, considered to precede the onset of potential diplopia. Secondary outcomes include safety at other time points, eligibility, recruitment/retention rates, adherence, clinical outcomes. We will summarise baseline characteristics for each group and assess the treatment effect using analysis of covariance. We will compare continuous clinical secondary endpoints between arms using linear mixed effect models, and report feasibility endpoints using descriptive statistics.

ETHICS/DISSEMINATION

This trial has been approved by the London-Brighton & Sussex Research Ethics Committee (18/LO/1204), National Health Service Health Research Authority and Medicines and Healthcare products Regulatory Agency. A lay advisory group will be involved with advising on and disseminating the results to non-professional audiences, including on websites of funder/participating institutions and inputting on healthcare professional audience children would like us to reach. Reporting to clinicians and scientists will be via internal and external meetings/conferences and peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03754153.

Reasons why we might want to question the use of patching to treat amblyopia as well as the reliance on visual acuity as the primary outcome measure

Recent evidence suggests that the primary deficit in amblyopia is loss of binocular vision and that the loss of monocular acuity is a secondary consequence. This new understanding derived from recent laboratory studies questions the present therapy and its primary acuity-based endpoint, which have been the gold standard in the treatment of this condition for the past 200 years.

Development and validation of a new method for visual acuity assesment on tablet in pediatric population: eMOVA test

BACKGROUND

Amblyopia is a major public health concern. Its screening and management require reliable methods of visual acuity assessment. New technologies offer nowadays many tests available on different app stores for smartphone or tablet but most of them often lack of scientific validation for a medical use. The aim of our study was to attempt validating a tablet-based near visual acuity test adapted to the pediatric population: the eMOVA test (electronic Measurement Of Visual Acuity) by comparing visual acuity measured with more conventional test.

METHODS

A cohort of 100 children aged 3 to 8 attending the ophthalmic-pediatric for eye examination between September 2016 and June 2017 were included in the study. Near visual acuity was assessed on participants using both the eMOVA test and a Standard test (Rossano-Weiss test). Duration of each test, its comprehension, its acceptability and the attention of the child during the test was also investigated.

RESULTS

The eMOVA test overestimated near visual acuity by 0.06 logMAR. This difference, statistically significant, was not clinically relevant. The duration of the eMOVA test was longer than the reference test, but less discomfort and preferred by children and their parents compared to standard tests.

CONCLUSION

The eMOVA test appears as a reliable test to assess near visual acuity in children. By its portability and efficiency, this application proved to be a relevant tool to be used for children eye examination in daily routine at the hospital.

Recent Treatment Advances in Amblyopia

Occlusion therapy has a long history as the gold standard treatment for amblyopia. Over the past two decades, large multicenter randomized controlled trials and objective dose-monitoring studies have characterized the effects of refractive correction, patching, and atropine penalization, providing insights into the impact of factors such as age and treatment dose. More recent approaches, whose development has been accelerated by advances in technology, are designed to provide different stimulation to the amblyopic eye and the fellow eye. This review explores a variety of such dichoptic approaches, categorized according to whether they primarily feature requisite use of the amblyopic eye in the face of fellow-eye masking, integration of visual information from both eyes, or reduction of stimulus salience in the fellow eye. It is still unclear whether dichoptic treatments are superior to traditional, low-cost treatment methods or whether their therapeutic mechanisms are fundamentally different from those of established treatments. Expected final online publication date for the Annual Review of Vision Science, Volume 8 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Efficacy of supplemental Occlu-pad therapy with partial occlusion in children with refractive anisometropic amblyopia

Purpose:

To study the efficacy of supplemental occlu-pad therapy with partial occlusion in children with refractive anisometropic amblyopia.

Methods:

Thirty-one children who did not improve after partial occlusion of 6 h for 6 months were supplemented with the use of occlu-pad for 1 h per day and three such sessions in a week.

Results:

The mean age was 6.8+/-1.4 years (range 5–9 years). A significant improvement of 3.2+/-1.3 lines in visual acuity was noticed at the end of 3 months of starting this supplemental therapy in children. Out of 31 children, 26 children improved at least 2 lines or more at the end of 3 months. All children (n = 9) having anisohyperopic amblyopia improved at the end of 3 months

Conclusion:

Occlu-pad is useful in supplementing occlusion therapy in cases of refractive amblyopia and is more effective in anisohyperopic amblyopia.

Randomized clinical trial of streaming dichoptic movies versus patching for treatment of amblyopia in children aged 3 to 7 years

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 < .001) and patching (0.06 ± 0.01 logMAR; p < 0.001) groups. There was no significant difference between groups (CI₉₅%: − 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).

The effects of optically and digitally simulated aniseikonia on stereopsis

Purpose

To simulate both lens‐induced and screen‐induced aniseikonia, and to assess its influence on stereopsis. Additionally, to determine if screen‐based size differences could neutralise the effects of lens‐induced aniseikonia.

Method

A four‐circle (4‐C) paradigm was developed, where one circle appears in front or behind the others because of crossed or uncrossed disparity. This stereotest was used for three investigations: (1) Comparison with the McGill modified random dot stereogram (RDS), with anisometropia introduced with +2 D spheres and cylinders, and with aniseikonia introduced with 6% overall and 6% meridional (×180, ×90) magnifiers before the right eye; (2) Comparison of lens‐induced and screen‐induced 6% overall and meridional magnifications and (3) Determining if lens and screen effects neutralised, by opposing 6% lens‐induced magnification to the right eye with screen‐inducements of either 6% left eye magnification or 6% right eye minification. A pilot study of the effect of masking versus not masking the surround was also conducted.

Results

The 4‐C test gave higher stereo‐thresholds than the RDS test by 0.5 ± 0.2 log units across both anisometropic and aniseikonic conditions. However, variations in power, meridian and magnification affected the two tests similarly. The pilot study indicated that surround masking improved neutralisation of screen and lens effects. With masking, lens‐induced and screen‐induced magnifications increased stereo‐thresholds similarly. With lens and screen effects opposed, for most participants stereo‐thresholds returned to baseline for overall and ×180 magnifications, but not for ×90 magnification. Only three of seven participants showed good compensation for ×90 magnification.

Conclusions

Effects of lens‐induced aniseikonia on stereopsis cannot always be successfully simulated with a screen‐based method. The ability to neutralise refractive aniseikonia using a computer‐based method, which is the basis of digital clinical measurement, was reasonably successful for overall and ×180 meridional aniseikonia, but not very successful for ×90 aniseikonia.

New treatment for amblyopia based on rules of synaptic plasticity: a randomized clinical trial

Amblyopia resulting from early deprivation of vision or defocus in one eye reflects an imbalance of input from the eyes to the visual cortex. We tested the hypothesis that asynchronous stimulation of the two eyes might induce synaptic plasticity and rebalance input. Experiments on normal adults showed that repetitive brief exposure of grating stimuli, with the onset of each stimulus delayed by 8.3 ms in one eye, results in a shift in perceptual eye dominance. Clinical studies (Clinical trial registration number: ChiCTR2100049130), using popular 3D movies with similar asynchrony between the two eyes (amblyopic eye stimulated first) to treat anisometropic amblyopia, established that just 10.5 h of conditioning over <3 weeks produced improvement that met criteria for successful treatment. The benefits of asynchronous conditioning accumulate over 20-30 45 min sessions, and are maintained for at least 2 years. Finally, we demonstrate that asynchronous binocular treatment alone is more effective than patching only. This novel treatment is popular with children and is some 50 times more efficient than patching alone.

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.

Binocular versus standard occlusion or blurring treatment for unilateral amblyopia in children aged three to eight years

BACKGROUND

Current treatments for amblyopia, typically patching or pharmacological blurring, have limited success. Less than two-thirds of children achieve good acuity of 0.20 logMAR in the amblyopic eye, with limited improvement of stereopsis, and poor adherence to treatment. A new approach, based on presentation of movies or computer games separately to each eye, may yield better results and improve adherence. These treatments aim to balance the input of visual information from each eye to the brain.  OBJECTIVES: To determine whether binocular treatments in children, aged three to eight years, with unilateral amblyopia result in better visual outcomes than conventional patching or pharmacological blurring treatment.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register), MEDLINE, Embase, ISRCTN, ClinicalTrials.gov, and the WHO ICTRP to 19 November 2020, with no language restrictions.

SELECTION CRITERIA

Two review authors independently screened the results of the search for relevant studies. We included randomised controlled trials (RCTs) that enrolled children between the ages of three and eight years old with unilateral amblyopia. Amblyopia was classed as present when the best-corrected visual acuity (BCVA) was worse than 0.200 logMAR in the amblyopic eye, with BCVA 0.200 logMAR or better in the fellow eye, in the presence of an amblyogenic risk factor, such as anisometropia, strabismus, or both. To be eligible, children needed to have undergone cycloplegic refraction and  ophthalmic examination, including fundal examination and optical treatment, if indicated, with stable BCVA in the amblyopic eye despite good adherence with wearing glasses. We included any type of binocular viewing intervention, on any device (e.g. computer monitors viewed with liquid-crystal display shutter glasses; hand-held screens, including mobile phones with lenticular prism overlay; or virtual reality displays). Control groups received standard amblyopia treatment, which could include patching or pharmacological blurring of the better-seeing eye. We included full-time (all waking hours) and part-time (between 1 and 12 hours a day) patching regimens. We excluded children who had received any treatment other than optical treatment; and studies with less than 8-week follow-up.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. The primary outcome of the review was the change from baseline of distance BCVA in the amblyopic eye after 16 (± 2) weeks of treatment, measured in logMAR units on an age-appropriate acuity test.

MAIN RESULTS

We identified one eligible RCT of conventional patching treatment versus novel binocular treatment, and analysed a subset of 68 children who fulfilled the age criterion of this review. We obtained data for the mean change in amblyopic eye visual acuity, adverse events (diplopia), and adherence to prescribed treatment at 8- and 16-week follow-up intervals, though no data were available for change in BCVA after 52 weeks. Risk of bias for the included study was considered to be low. The certainty of evidence for the visual acuity outcomes at 8 and 16 weeks of treatment and adherence to the study intervention was rated moderate using the GRADE criteria, downgrading by one level due to imprecision. The certainty of evidence was downgraded by two levels and rated low for the proportion of participants reporting adverse events due to the sample size.  Acuity improved in the amblyopic eye in both the binocular and patching groups following 16 weeks of treatment (improvement of -0.21 logMAR in the binocular group and -0.24 logMAR in the patching group, mean difference (MD) 0.03 logMAR (95% confidence interval (CI) -0.10 to 0.04; 63 children). This difference was non-significant and the improvements in both the binocular and patching groups are also considered clinically similar. Following 8 weeks of treatment, acuity improved in both the binocular and patching groups (improvement of -0.18 logMAR in the patching group compared to -0.16 logMAR improvement in the binocular-treatment group) (MD 0.02, 95% CI -0.04 to 0.08). Again this difference was statistically non-significant, and the differences observed between the patching and binocular groups are also clinically non-significant. No adverse event of permanent diplopia was reported. Adherence was higher in the patching group (47% of participants in the iPad group achieved over 75% compliance compared with 90% of the patching group).  Data were not available for changes in stereopsis nor for contrast sensitivity following treatment.

AUTHORS' CONCLUSIONS

Currently, there is only one RCT that offers evidence of the safety and effectiveness of binocular treatment. The authors are moderately confident that after 16 weeks of treatment, the gain in amblyopic eye acuity with binocular treatment is likely comparable to that of conventional patching treatment. However, due to the limited sample size and lack of long term (52 week) follow-up data, it is not yet possible to draw robust conclusions regarding the overall safety and sustained effectiveness of binocular treatment. Further research, using acknowledged methods of visual acuity and stereoacuity assessment with known reproducibility, is required to inform decisions about the implementation of binocular treatments for amblyopia in clinical practice, and should incorporate longer term follow-up to establish the effectiveness of binocular treatment. Randomised controlled trials should also include outcomes reported by users, adherence to prescribed treatment, and recurrence of amblyopia after cessation of treatment.

An updated review about perceptual learning as a treatment for amblyopia

The purpose of our work is to do an update of recent investigations about amblyopia treatment based on perceptual learning, dichoptic training and videogames. Therefore, we conducted a search of the studies published about this subject in the last six years. The review shows that the investigations during that period have used several kinds of treatments regarding their design (e.g., type of stimulus and context used, duration of the training), and in a wider range of age that also include adults. Most of the studies have found an improvement in some mono and binocular visual functions, such as visual acuity, contrast sensitivity and stereopsis, which for now, it seems advisable that these processes could be used, as an alternative or a complement of the traditional passive therapy. Nevertheless, it would be plausible to conduct additional, controlled and random, clinical trials in order to discover in a more deeply way which perceptive learning method of treatment is more effective for the improvement of visual functions and for how long the effects of the treatment could persist.

Anaglyphic Three-Dimensional Movie: A Simple Binocular Method to Treat Anisometropic or Strabismic Amblyopia in Adults

Purpose

To evaluate the efficacy of anaglyphic three-dimensional movies to treat adults with anisometropic or strabismic amblyopia.

Methods

This is an interventional case series. The seven cases were put on a trial frame containing subjective refraction, fogging plus lenses for the dominant eye, correcting prism, and anaglyphic red-cyan plastic spectacles. Patients participated in 20 sessions of 1.5 h of anaglyphic three-dimensional animated movie watching in the office. Significant visual acuity (VA) improvement was defined as improvement ≥0.2 in logMAR values. Change in octaves of stereopsis was defined as halving the arcsec or 0.3 change in log arcsec.

Results

The average age was 26.9 ± 10.0 (16-42) years. The mean VA in amblyopic eye improved significantly from 0.42 ± 0.19 (0.15-0.7) logMAR to 0.25 ± 0.15 (0.1-0.5) logMAR after completion of sessions (P = 0.02), and four cases showed significant VA improvement. The mean stereoacuity improved significantly from 2.6 ± 0.3 (2.1-2.9) log arcsec to 2.1 ± 0.5 (1.7-2.9) log arcsec (P = 0.04). Four cases showed ≥2 octaves improvements in stereopsis.

Conclusion

A simple and readily available method of amblyopia treatment can be effective in some adult cases.

Management of amblyopia in pediatric patients: Current insights

Amblyopia is a cause of significant ocular morbidity in pediatric population and may lead to visual impairment in future life. It is caused due to formed visual deprivation or abnormal binocular interactions. Several risk factors in pediatric age group may lead to this disease. Author groups have tried managing different types of amblyopia, like anisometropic amblyopia, strabismic amblyopia and combined mechanism amblyopia, with optical correction, occlusion therapy, penalization, binocular therapy and surgery. We review historical and current management strategies of different types of amblyopia affecting children and outcomes in terms of visual acuity, binocularity and ocular deviation, highlighting evidence from recent studies. Literature searches were performed through Pubmed. Risk factors for amblyopia need to be identified in pediatric population as early in life as possible and managed accordingly, as visual outcomes in amblyopia are best if treated at the earliest. Although, monocular therapies like occlusion or penalization have been shown to be quite beneficial over the years, newer concepts related to binocular vision therapy are still evolving.

Recent Advances in Screening and Treatment for Amblyopia

Amblyopia is the most common cause of monocular visual impairment in children, with a prevalence of 2-3%. Not only is visual acuity reduced in one eye but binocular vision is affected, fellow eye deficits may be present, eye-hand coordination and reading can be affected, and self-perception may be diminished. New technologies for preschool vision screening hold promise for accessible, early, and accurate detection of amblyopia. Together with recent advances in our theoretical understanding of amblyopia and technological advances in amblyopia treatment, we anticipate improved visual outcomes for children affected by this very common eye condition. This article is based on previously conducted studies and does not contain any new studies with human participants or animals performed by any of the authors.

Stereoacuity after Successful Occlusion Therapy in Children with Anisometropic Amblyopia

Purpose: To compare the stereoacuity between patients with anisometropic amblyopia who were treated and achieved normal visual acuity (VA) and normal children and evaluate the factors associated with stereoacuity.Methods: We retrospectively reviewed the records of 37 pediatric patients with anisometropic amblyopia who recovered to normal VA with glasses and occlusion treatment (amblyopia group) and 34 normal children (control group). The Worth 4-dot test, Lang II test, Titmus test, and TNO test were performed to measure stereoacuity. Clinical characteristics were compared between the two groups, and factors affecting stereoacuity outcomes were also analyzed in the amblyopic group.Results: The mean age at diagnosis of amblyopia was 5.3 ± 1.4 years, and the mean VAs at diagnosis were 0.41 ± 0.24 and 0.06 ± 0.07 in amblyopic and fellow eyes, respectively. The mean duration of occlusion was 19.00 ± 9.44 months, and VA of amblyopic eyes improved to 0.04 ± 0.04 after occlusion treatment. The patient characteristics did not differ significantly between the two groups, except for the final VA of the amblyopic eye. The final mean logarithm of minimal angle of resolution VA of the amblyopic eye in the amblyopia group was significantly worse than that in the control group. The number of patients with normal stereoacuity was significantly lower in the amblyopia group than in the control group on Lang II, Titmus, and TNO tests. Factors associated with poor stereoacuity were severe amblyopia in the Lang II test and poor post-treatment VA of the amblyopic eye in the Titmus test.Conclusions: Stereoacuity was worse in the amblyopia group than in the control group, despite normal visual development. The depth of amblyopia and post-treatment VA were associated with stereoacuity outcomes. Thus, VA improvement should be closely monitored in the amblyopic eye to obtain good stereoacuity.

Comparison of binocular game and patching in treating mild to moderate anisometropic amblyopia: a study protocol for a randomized controlled trial

Background

Amblyopia, as a neurodevelopmental preventable visual disorder, affects approximately 1.1 % in Asia. A binocular approach to treating amblyopia has been recently proposed. Whether the binocular playing game treatment is comparable to patching treatment needs further randomized clinical trials. To address this, the present research, designs, develops, and evaluates a new binocular game to treat amblyopia.

Methods

This study has been designed as a non-inferiority, randomized, two parallel-group, controlled trial. Forty-four patients between 4 and 12 years diagnosed with amblyopia will be randomly assigned to the control and intervention groups. In the intervention group, amblyopia treatment is provided with red-green anaglyphic glasses and a red filter placed in front of the amblyopic eye, along with a game to be played for 30 min twice a day. Those in the control group will receive patch therapy according to amblyopia treatment study protocol. The primary outcome is to change visual acuity in the amblyopic eye from the baseline to 3 months after randomization.

Ethics and dissemination

The Ethics Committee of Mashhad University of Medical sciences’ approval date was February 28, 2018, with a reference code of IR.MUMS.fm.REC.1396.783. Thus far, the recruitment of participants has not been completed and is scheduled to end in September 2021. The results will be disseminated in a peer-reviewed journal.

Trial registration

Iranian Registry of Clinical Trials IRCT20180217038768N1. Registered on 22 April 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05735-2.

Binocular treatment for amblyopia: A meta-analysis of randomized clinical trials

Background

To date, there is still no consensus regarding the effect of binocular treatment for amblyopia. The purpose of this systematic review and meta-analysis was to summarize the available evidence to determine whether binocular treatment is more effective than patching in children with amblyopia.

Methods

Four electronic databases (PubMed, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials) were searched for studies that compared binocular treatment and patching in children with amblyopia. The outcome measures were visual acuity and stereopsis. Pooled effects sizes were calculated with a random-effect model. The standardized difference in means (SDM) with 95% confidence intervals (CI) was calculated. Sensitivity analysis and assessment of publication bias were performed.

Results

Five randomized clinical trials were included. No significant difference in visual acuity between patients treated with binocular treatment and patching was observed (SDM = -0.12; 95% CI: -0.45–0.20; P = 0.464). No significant difference in stereopsis between patients treated with binocular treatment and patching was observed (SDM = -0.07; 95% CI: -0.61–0.48; P = 0.809). For both variables, the between-study heterogeneity was high (respectively, I² = 61% and I² = 57%).

Conclusions

This meta-analysis found no convincing evidence supporting the efficacy of binocular treatment as an alternative to conventional patching. Therefore, the binocular treatment cannot fully replace traditional treatment but, to date, it can be considered a valid complementary therapy in peculiar cases. Further studies are required to determine whether more engaging therapies and new treatment protocols are more effective.

Video game treatment of amblyopia

Amblyopia is visual impairment characterized by a structurally normal eye showing significantly lower visual acuity than the fellow eye. Traditional treatment of amblyopia includes patching the good eye to force the amblyopic eye to work during normal daily activities; however, this approach is are limited by low compliance. Recently, researchers proposed a new treatment for amblyopia: video game playing. In the current review, we discuss whether video game playing can treat amblyopia, whether video game playing could better treat amblyopia than traditional treatments, and how the video game treats amblyopia and its possible mechanism. Based on results from our literature review and meta-analysis, we suggest there is strong evidence for the effectiveness of video game treatments. Moreover, multiple factors within and outside of video games could influence the treatment effect.

Randomized Controlled Trial of a Dichoptic Digital Therapeutic for Amblyopia

PURPOSE

Digital therapeutics are a new class of interventions that are software driven and are intended to treat various conditions. We developed and evaluated a dichoptic digital therapeutic for amblyopia, a neurodevelopmental disorder for which current treatments may be limited by poor adherence and residual vision deficits.

DESIGN

Randomized controlled trial.

PARTICIPANTS

One hundred five children 4 to 7 years of age with amblyopia were enrolled at 21 academic and community sites in the United States. Participants were randomized 1:1 to the treatment or comparison group, stratified by site.

METHODS

We conducted a phase 3 randomized controlled trial to evaluate the safety and efficacy of a dichoptic digital therapeutic for amblyopia. Participants in the treatment group used the therapeutic at home for 1 hour per day, 6 days per week and wore glasses full-time. Participants in the comparison group continued wearing glasses full-time alone.

MAIN OUTCOME MEASURES

The primary efficacy outcome was change in amblyopic eye visual acuity (VA) from baseline at 12 weeks, and VA was measured by masked examiners. Safety was evaluated using the frequency and severity of study-related adverse events. Primary analyses were conducted using the intention-to-treat population.

RESULTS

Between January 16, 2019, and January 15, 2020, 105 participants were enrolled; 51 were randomized to the treatment group and 54 were randomized to the comparison group. At 12 weeks, amblyopic eye VA improved by 1.8 lines (95% confidence interval [CI], 1.4-2.3 lines; n = 45) in the treatment group and by 0.8 lines (95% CI, 0.4-1.3 lines; n = 45) in the comparison group. At the planned interim analysis (adjusted α = 0.0193), the difference between groups was significant (1.0 lines; P = 0.0011; 96.14% CI, 0.33-1.63 lines) and the study was stopped early for success, according to the protocol. No serious adverse events were reported.

CONCLUSIONS

Our findings support the value of the therapeutic in clinical practice as an effective treatment. Future studies should evaluate the therapeutic compared with other methods and in additional patient populations.

Could virtual reality applications pose real risks to children and adolescents? A systematic review of ethical issues and concerns

Virtual reality technologies (VRTs) are high-tech human-computer interfaces used to develop digital content and can be applied to multiple different areas, often offering innovative solutions to existing problems. A wide range of digital games is being also developed with VRTs and together with their components, the games' structural elements are appealing to children and engaging them more in virtual worlds. Our research interest is directed towards children's development and the effects of VRTs within gaming environments. Contemporary psychology studies perceive human development as a holistic and lifelong process with important interrelationships between physical, mental, social and emotional aspects. For the objectives and scope of this work, we examine children development across three domains: physical, cognitive and psychosocial. In this context, the authors review the literature on the impact of VRTs on children, in terms of software and hardware. Since research requires an wide-ranging approach, we study the evidence reported on the brain and neural structure, knowledge, behaviour, pedagogy, academic performance, and wellness. Our main concern is to outline the emerging ethical issues and worries of parents, educators, ophthalmologists, neurologists, psychologists, paediatricians and all relevant scientists, as well as the industry's views and actions. The systematic review was performed on the databases Scopus, IEEE Xplore, PubMed, and Google Scholar from 2010 to 2020 and 85 studies were selected. The review concluded that findings remain contradictory especially for the psychosocial domain. Official recommendations from organizations and well-documented researches by academics on child well-being are reassuring if health and safety specifications and particularly the time limit are met. Research is still ongoing, constantly updated and consist of a priority for the scientific community given that technology evolves.

Binocular fusion enhances the efficiency of spot-the-difference gameplay

Spot-the-difference, the popular childhood game and a prototypical change blindness task, involves identification of differences in local features of two otherwise identical scenes using an eye scanning and matching strategy. Through binocular fusion of the companion scenes, the game becomes a visual search task, wherein players can simply scan the cyclopean percept for local features that may distinctly stand-out due to binocular rivalry/lustre. Here, we had a total of 100 visually normal adult (18-28 years of age) volunteers play this game in the traditional non-fusion mode and after cross-fusion of the companion images using a hand-held mirror stereoscope. The results demonstrate that the fusion mode significantly speeds up gameplay and reduces errors, relative to the non-fusion mode, for a range of target sizes, contrasts, and chromaticity tested (all, p<0.001). Amongst the three types of local feature differences available in these images (polarity difference, presence/absence of a local feature difference and shape difference in a local feature difference), features containing polarity difference was identified as first in ~60-70% of instances in both modes of gameplay (p<0.01), with this proportion being larger in the fusion than in the non-fusion mode. The binocular fusion advantage is lost when the lustre cue is purposefully weakened through alterations in target luminance polarity. The spot-the-difference game may thus be cheated using binocular fusion and the differences readily identified through a vivid experience of binocular rivalry/lustre.

Binocular visual deficits at mid to high spatial frequency in treated amblyopes

Amblyopia (lazy eye) is a neurodevelopmental disorder of vision with no ocular pathology. The loss of vision in the amblyopic eye is assumed to be the main deficit in amblyopia, which has resulted in visual acuity (VA) being the primary outcome measure for treatment. Here we used a binocular orientation combination task to quantitatively assess the binocular status by measuring the binocular balance. We set out to determine whether amblyopes who reach the acuity-based end point have a residual binocular imbalance. Our results suggest that even amblyopes who have regained normal acuity have residual binocular deficits over a wide range of spatial frequencies. A further control study suggests that these binocular deficits could not be explained by any residual contrast sensitivity deficits of the amblyopic eye. Consequently, amblyopia is not the primary problem and VA is not the appropriate end point measure.

Current Management of Amblyopia with New Technologies for Binocular Treatment

Amblyopia is the most common cause of monocular poor vision affecting up to 3.7% of the global population. Classically, the first step in treatment has been optical correction, followed by patching and/or pharmacological treatment. However, this is an evolving scenario, since researchers and clinicians are interested in new binocular treatments due to the increasing development of new technologies. In this article main, current binocular treatments as Dig Rush, falling blocks, I-BiT, Occlu-tab, Vivid Vision, and movies are reviewed for binocular amblyopia management.

Portable rotating grating stimulation for anisometropic amblyopia with 6 months training

Treatment of grating stimulation has been used in amblyopia for decades, but high dropout rate and inconvenience for daily practice occur in previous studies. We developed a home-based portable system with rotating grating stimulation on a tablet. Thirty anisometropic amblyopic children were randomly allocated into the control or Grating group. They drew contour of the picture under patch of a better eye for 6 months. Best-corrected visual acuity (BCVA), grating acuity (GA), and contrast sensitivity (CS) were assessed at the baseline, 1st, 2nd, 3rd, and 6th months of training. All participants completed the 6-month training. Patched eyes of both groups exhibited no difference. Trained eyes of the control group had significantly slight improvement in BCVA and GA. In particular, the Grating group exhibited significantly higher BCVA, GA, and CS compared with those of the control group at the 3rd and 6th months of training. Moreover, percentage of the Grating group with great improvement (BCVA ≥ 0.3 or CS ≥ 0.3) was significantly larger than those of the control group at the 3rd or 6th months of training. The portable grating stimulation system demonstrates its trainability by no dropout and effectiveness by significant improvements in all assessments through a well experimental design.

Trial Registration: ClinicalTrials.gov NCT04213066, registered 30/12/2019, https://clinicaltrials.gov/ct2/show/NCT04213066.