Amblyopia is a leading cause of preventable visual impairment in children, traditionally characterized by reduced best-corrected visual acuity without overt ocular pathology. While structural retinal findings assessed by optical coherence tomography (OCT) remain controversial, functional retinal assessment using microperimetry has emerged as a promising diagnostic adjunct. This review highlights the clinical relevance of retinal sensitivity and fixation stability as objective biomarkers in amblyopia. Following PRISMA 2020 guidelines, a comprehensive literature search (2015–2025) was conducted across PubMed, Scopus, Web of Science, Embase, and Cochrane Library. Studies including quantitative measures of macular sensitivity and fixation stability (BCEA, P1, P2) in anisometropic, strabismic, deprivation, and high myopic amblyopia were analyzed. Evidence consistently demonstrates reduced macular sensitivity and impaired fixation stability in amblyopic eyes compared to fellow or control eyes, with strabismic and mixed amblyopia showing the greatest deficits. Fixation instability, quantified by increased Bivariate Contour Ellipse Area (BCEA) and reduced P1/P2 indices, correlates significantly with visual acuity and stereopsis. Notably, emerging data indicate subtle fixation abnormalities in fellow eyes, supporting a binocular dysfunction model. Structure–function correlations between ganglion cell complex thickness and macular sensitivity further underscore the interplay between retinal integrity and functional performance. However, motion perception deficits appear partly independent of fixation instability, suggesting additional cortical involvement. Microperimetry and infrared eye-tracking provide sensitive, reproducible measures that enhance diagnostic precision and therapeutic monitoring. Integrating structural and functional biomarkers may refine amblyopia evaluation and guide individualized rehabilitation strategies.
Majumder et al. (2026) studied this question.