Altered retinal vasculature in amblyopia

Amblyopia is a developmental visual disorder characterized by reduced vision in one eye and has traditionally been considered a cortical condition, with no involvement of retinal structures or functions. However, recent evidence suggests that retinal vasculature may be affected in individuals with amblyopia. In this study, we investigated whether there are differences in richness and density of retinal blood vessels between individuals with amblyopia and normal controls. We used the Spatial Attention-UNet network to segment retinal blood vessels from OCT fundus images obtained from both amblyopic and fellow eyes of 23 adults with amblyopia (12 anisometropic; 11 strabismic) and the right eye of 40 control participants. We then used four features to quantify the segmented retinal vasculature: vascular area (number of pixels within segmented vessels), fractal dimension (a measurement of vascular network density distribution pattern), vascular skeleton length (pixel count of the skeletonized vessel tree), and number of vascular bifurcation points (branching complexity of the vessel skeleton). For our sample of amblyopic participants, we found no statistically significant differences between amblyopic and fellow eyes, or between anisometropic and strabismic groups, for the four vasculature features. Compared with normal control eyes, vascular area, fractal dimension and vascular skeleton length were all lower in both amblyopic and fellow eyes of amblyopic participants. These results indicate alterations in retinal vasculature in eyes (both amblyopic and fellow eyes) of individuals with amblyopia, suggesting that further research is warranted to investigate retinal vasculature as a potential biomarker for detecting and managing amblyopia.