OCT Assessment of Deep Optic Nerve Head, Subfoveal Choroidal Thickness, and Retinal Layers in Unilateral Anisometropic Amblyopia

OBJECTIVES: To evaluate retinal layers, subfoveal choroidal thickness, and optic nerve head parameters in adults with unilateral anisometropic amblyopia using optical coherence tomography.
METHODS: This comparative cross-sectional study included 41 adults with unilateral anisometropic amblyopia and 35 healthy controls. Optical coherence tomography measurements were obtained from amblyopic eyes, fellow eyes, and control eyes. Retinal analysis included the nerve fiber layer, inner plexiform layer, outer plexiform layer, inner segment/outer segment (IS/OS) junction, retinal pigment epithelium, and subfoveal choroidal thickness. Peripapillary retinal nerve fiber layer, ganglion cell complex, mean macular thickness, Bruch’s membrane opening, Bruch’s membrane opening-minimum rim width, and lamina cribrosa-related parameters were also assessed. Comparisons were performed using linear mixed-effects models, with Bon-ferroni correction for post hoc analyses.
RESULTS: After adjustment for age, significant between-group differences were mainly limited to the IS/OS parameter, mean macular thickness, and selected lamina cribrosa measurements. IS/OS was significantly higher in amblyopic eyes than in control eyes (172.55±42.50 vs 151.26±26.14; overall p=0.029, adjusted p=0.029), whereas mean macular thickness was lower in amblyopic eyes (246.00±20.90 vs 261.99±14.67; overall p=0.015, adjusted p=0.016). Temporal lamina cribrosa curve value (p=0.005), superior lamina cribrosa depth (p=0.016), temporal lamina cribrosa depth (p=0.017), and tempo-ral lamina cribrosa width (p=0.005) also differed significantly after age adjustment. Retinal nerve fiber layer, ganglion cell complex, Bruch’s membrane opening, Bruch’s membrane opening-minimum rim width, subfoveal choroidal thickness, and lamina cribrosa curvature index showed no significant differences.
DISCUSSION AND CONCLUSION: In adults with unilateral anisometropic amblyopia, structural changes after age adjustment were subtle and region-specific rather than diffuse. The main differences involved the IS/OS parameter, mean macular thickness, and selected lamina cribrosa-related measurements, while other retinal, choroidal, and optic nerve head parameters were largely similar across groups.

Keywords: Amblyopia, anisometropia, optical coherence tomography, retinal layers, choroid, lamina cribrosa