Macular ultrastructural features in amblyopia using high-definition optical coherence tomography.

Purpose: To study macular morphology in amblyopic eyes using high-definition spectral domain optical coherence tomography (SD-OCT) and to compare the findings with fellow eyes.

Methods: This was a prospective institutional study of patients ≥6 years of age with unilateral amblyopia. Enhanced high-definition single line macular scans of amblyopic eyes were obtained using SD-OCT and compared with fellow eyes. Scans were evaluated qualitatively for structural differences. Central foveal thickness was measured and areas of the different retinal layers were computed within 500 µm from the foveal centre nasally and temporally.

Results: Forty-five patients with unilateral amblyopia were included: 25 with strabismic and 20 with anisometropic amblyopia with a mean age of 24.8 years. Qualitatively, the bulge in the inner segment/outer segment junction of the central fovea was noted to be attenuated or absent in 60% of amblyopic eyes compared with 29% of normal eyes, p=0.02. Also, amblyopic eyes demonstrated a shallow foveal pit compared with normal fellow eyes. Mean foveal thickness was significantly increased in amblyopic (228.56 µm) versus fellow eyes (221.72 µm), p=0.03. Upon exploring different retinal layers, the temporal inner nuclear layer area was increased (p=0.04) while the outer nuclear layer area was decreased (p=0.04) in amblyopic eyes compared with fellow eyes.

Conclusions: Using enhanced high-definition SD-OCT, amblyopic eyes demonstrated qualitative and quantitative differences in macular features, possibly representing signs of immaturity compared with normal fellow eyes.