Structural and microvascular disparities in myopic and hyperopic anisometropic amblyopic eyes: A comprehensive biometry, optical coherence tomography, and optical coherence tomography angiography study

PURPOSE: The objective of the study is to evaluate ocular biometric measurements, retinal and choroidal characteristics in individuals aged six years and older with unilateral anisometropic amblyopia.
METHODS: Fifty-eight participants were selected and assigned to two groups: Myopic anisometropic and hyperopic anisometropic amblyopia. All participants received a standardized ophthalmic work-up comprising visual-acuity testing, refraction, ocular biometry, and multimodal retinal imaging with optical coherence tomography (OCT) and OCT angiography (OCTA).
RESULTS: he mean age was 31.12±2.49 years (range: 6–60 years). Visual acuity, spherical and cylindrical refractive error, and spherical equivalent differed significantly between the amblyopic and fellow eyes in both myopic and hyperopic groups (p<0.001 for all). Axial length and vitreous length differed significantly between the hyperopic (p=0.008 and p=0.003, respectively) and myopic amblyopic (p<0.001 for both) eyes compared to their fellow eyes. Retinal thickness measurements revealed that the myopic anisometropic amblyopic eyes had significantly thinner superior temporal, inferior temporal, and global peripapillary retinal nerve fiber layer thickness values compared to hyperopic anisometropic amblyopic eyes (p=0.022, p=0.002, and p=0.007, respectively). Evaluation of the microvascular features in the macular and peripapillary regions using OCTA revealed that the myopic amblyopic eyes had significantly lower mean superior peripapillary vessel density values in both the superficial capillary plexus (p=0.041) and choriocapillaris (p=0.033) segments compared to fellow eyes.
CONCLUSION: A holistic evaluation of the anatomical characteristics and microvascular structures of ocular tissues may be valuable in elucidating the mechanisms of amblyopia in anisometropic amblyopic eyes.

Keywords: Anisometropia, anisometropic amblyopia, optical coherence tomography angiography, optical coherence tomography.