The assessment of posterior ocular structures in Turkish children with anisometropic amblyopia

BACKGROUNDS: To investigate whether unilateral amblyopia in childhood is associated with structural alterations in the retina, optic nerve head, and lamina cribrosa by means of optical coherence tomography (OCT). METHODS: In this cross-sectional study, 31 children with unilateral anisometropic amblyopia and 30 age- and sex-matched healthy controls were included. The amblyopia group contributed 31 amblyopic eyes and 31 fellow eyes, and both eyes of healthy controls were analyzed as right and left control eyes. Retinal layer segmentation, macular thickness, peripapillary retinal nerve fiber layer (RNFL), ganglion cell complex (GCC), optic nerve head parameters, lamina cribrosa-related measurements, and subfoveal choroidal thickness were assessed using spectral-domain OCT. To account for within-subject inter-eye dependency, ocular parameters were analyzed using a linear mixed model with eye group as a fixed effect, subject identity as a random effect, and age as a covariate. RESULTS: Outer retinal layers and subfoveal choroidal thickness were comparable across groups. Macular thickness was significantly lower in both amblyopic and fellow eyes than in control eyes, whereas no difference was found between amblyopic and fellow eyes. Peripapillary RNFL analysis showed a sector-specific difference limited to the inferior quadrant, with thinner RNFL in fellow eyes than in control eyes, while GCC parameters did not differ significantly. Conventional optic disc morphometric parameters, including disc area, cup area, and horizontal and vertical cup-to-disc ratios, were similar among the groups. In contrast, linear mixed-model analysis identified sector-specific differences in several deep optic nerve head parameters, including BMO, BMO-MRW, LCD, and LCCI, particularly in the superior, inferior, temporal, and nasal sectors. CONCLUSIONS: Unilateral anisometropic amblyopia in children was associated with selective and region-specific posterior segment structural differences rather than diffuse retinal damage. The main findings were reduced macular thickness in both amblyopic and fellow eyes, a sector-specific difference confined to the inferior RNFL, and significant alterations in several deep optic nerve head parameters related to BMO, BMO-MRW, LCD, and LCCI, while outer retinal layers, GCC, conventional optic disc morphometric parameters, and subfoveal choroidal thickness remained largely preserved. The presence of similar changes in fellow eyes suggests that amblyopia may be associated with structural alterations beyond the clinically amblyopic eye.