The assessment of morphological changes in the retina in amblyopia using optical coherence tomography image segmentation

Abstract

Purpose: The aim of this study was to evaluate the structural changes of the macula in patients with unilateral amblyopia using optical coherence tomography (OCT) image segmentation.

Methods: 38 consecutive patients (16 male; mean age 32.4 ± 17.6 years; range 6-67 years) with unilateral amblyopia were included. OCT examinations were performed using a time-domain OCT device. The OCT scans were processed with a custom-built OCT image analysis software (OCTRIMA). The axial length (AL) was measured for each eye using a LenStar LS 900 device. Macular layer thickness, AL and manifest spherical equivalent refraction (MRSE) of the amblyopic eye were compared to that of the fellow eye. The effect of the type of amblyopia (strabismus without anisometropia, anisometropia without strabismus, strabismus with anisometropia) on macular layer thickness values was also assessed.

Results: A significant difference was observed between the amblyopic and fellow eyes in MRSE and AL in all subgroups. Comparing the amblyopic and fellow eyes, statistically significant difference was found only in the thickness of the outer nuclear layer in the central region using linear mixed model analysis keeping AL and age under control (p=0.032). There was no significant difference in interocular difference in the thickness of any macular layers between the subgroups with one-way between-groups ANCOVA while statistically controlling for interocular difference in AL and age.

Conclusions: According to our results, subtle changes are present in amblyopic eyes affecting the outer nuclear layer of the fovea suggesting the possible involvement of the photoreceptors. However, further studies are warranted to support this hypothesis.

Keywords: 417 amblyopia • 549 image processing • 688 retina