Fig. 2

Baseline retinal differences between PD patients and controls. (A) A funduscopic SLO image with superimposed macular parcellation into concentric rings centered on the fovea. Continuous lines represent the ETDRS grid annuli (with diameters of 1-mm, 3-mm, and 6-mm), while dashed lines indicate the additional macular subdivisions introduced in this study, dividing the macula into concentric circular zones spaced 1-mm apart. The blue line represents the region where the B-scan shown in B was acquired. (B) A horizontal OCT B-scan passing through the fovea. The GCIPL layer is highlighted in blue. (C) The circular plot on the left illustrates estimated differences in GCIPL thickness between PD patients and controls at baseline. The combined boxplots and half violin plots on the right depict the distribution of the mean GCIPL thickness across different macular regions for each group. Statistically significant differences are indicated with asterisks (**p < 0.01)

Abbreviations: ETDRS, Early Treatment Diabetic Retinopathy Study; GCIPL: ganglion cell–inner plexiform layer complex; OCT, Optical Coherence Tomography; SLO, Scanning Laser Ophthalmoscopy