Evaluation of amblyopic eyes with optical coherence tomography angiography and electrophysiological tests

Abstract

Purpose: To investigate the structural and functional changes of the retina and optic nerve in amblyopia. Methods: Eighteen patients with unilateral anisometropic amblyopia and 27 age-matched healthy controls were involved in this study. All patients underwent optical coherence tomography angiography (OCTA), pattern visual evoked potential (pVEP), and flash electroretinogram (fERG). Results: There was no statistically significant difference in terms of the fovea] avascular zone (FAZ), perifoveal superficial density, whole superficial density, parafoveal deep density, perifoveal deep density among the eyes (P > 0 0.05). Significant differences were found only in superficial capillary plexus (SCP) vessel density in whole (P = 0.029) and parafoveal (P = 0.008) image. In electrophysiological tests, while VEP latencies of the amblyopic eyes increased compared to nonamblyopic eyes and controls (P = 0.027), VEP amplitudes decreased in amblyopic and nonamblyopic eyes compared to controls (P = 0.01), amplitudes of the rod (P = 0.027) and cones (P < 0.001) also decreased in amblyopic eyes compared to nonamblyopic and healthy eyes. When we assessed the correlation between the parameters of OCTA and electrophysiological test, only a significant correlation was found between parafoveal SCP vessel density and VEP amplitudes (r = 0.341). Conclusion: We found a significant decrease only in SCP vessel density of the OCTA parameters in amblyopic eyes compared to healthy eyes. We detected a significant relationship between parafoveal SCP vessel density and VEP parameters, which might be associated with the underlying pathophysiology of the amblyopia.