Effectiveness of Psychophysical Visual Stimuli-Based Interventions in Amblyopia Treatment: A Systematic Review

Introduction: Active vision therapy, integrating perceptual learning with dichoptic or binocular environments, has shown potential effectiveness in treating amblyopia. However, uncertainties remain regarding the optimal types of stimuli and the best approaches and sequences for their delivery. This systematic review aimed to evaluate the effectiveness of psychophysical visual-stimuli-based interventions, particularly perceptual learning and dichoptic training, in treating amblyopia. Materials and Methods: A comprehensive literature search across major databases, such as PubMed and Google Scholar, yielded 26 studies involving 993 patients with amblyopia. These studies investigated various visual training methods, including perceptual learning, dichoptic stimulation, and combinations of both, using stimuli, such as Gabor patches, letter optotypes, Vernier stimuli, and random-dot stereograms. Results: The findings indicate that perceptual learning enhances visual acuity, contrast sensitivity, and stereopsis by leveraging neural plasticity, even in adult patients. Dichoptic training, which engages both eyes simultaneously, shows promise in reducing suppression and improving binocular integration, offering potential advantages over traditional patching therapy. Gabor patches emerged as particularly effective, stimulating the visual cortex to drive neural efficiency. Conclusion: Vision therapy is an effective strategy for treating amblyopia and may reduce overall treatment time when used in conjunction with patching. In addition, it is crucial to tailor stimuli to match the individual characteristics of each patient during monocular and binocular training.