Retinal phenotyping of variants of Alzheimer's disease using ultra‐widefield retinal images

BACKGROUND: Posterior cortical atrophy (PCA) is the most common atypical variant of Alzheimer's disease (AD). Changes associated with PCA in the brain affect the visual cortex, but little is known about retinal changes in PCA. In this study, we explored retinal phenotypic variations in typical AD (tAD) and PCA. METHODS: Retinal phenotyping was carried out on ultra‐widefield (UWF) images of 69 control, 24 tAD, and 25 PCA participants. RESULTS: Individuals with tAD (odds ratio [OR] = 2.76 [confidence interval (CI):1.24 to 6.10], P = .012) and PCA (OR = 3.40 [CI:1.25 to 9.22], P = .016) were more likely phenotyped as hard drusen. tAD (OR = 0.34 [CI:0.12 to 0.92], P = .035) were less likely to have soft drusen compared to control. Almost 3‐fold increase in reticular pseudodrusen formation in tAD (OR = 2.93 [CI:1.10 to 7.76], P = .030) compared to control was estimated. DISCUSSION: Studying the peripheral retina may contribute to a better understanding of differences in retinal phenotypes of different AD variants.