Choroidal and retinal vascular changes in adults with Down syndrome: Insights into the Alzheimer's disease continuum

INTRODUCTION: Retinal and choroidal vascular changes have been proposed as a non-invasive central nervous system (CNS) proxy for clinical trials in Alzheimer's disease (AD). However, their role in Down syndrome (DS), the largest genetically predisposed group for AD, remains unclear. METHODS: We conducted ultra-widefield and optical coherence tomography imaging on 24 individuals with DS and 17 controls and extracted various vascular parameters. Data were analyzed using logistic and linear regression models. RESULTS: The DS retinae exhibited supernumerary vessels that were wider and thinned more rapidly along their paths (p = 0.01). There was a more complex central retinal (p = 0.047) and a less complex peripheral retinal vascular tree (p = 0.001), with increased numbers of peripheral microvascular abnormalities (p = 0.038) and reduced choroid vascularity index in DS (p < 0.001). DISCUSSION: We found that retinal and choroidal vascular changes are present in DS adults before the clinical onset of AD and might become early surrogates for cerebral vascular abnormalities. HIGHLIGHTS: Eye imaging in DS showed retinal and choroidal changes seen in AD. Far peripheral retinal microaneurysms and hemorrhages associated to DS. Wider and faster thinning vessels associated to DS. Reduced vascular tree complexity in the peripheral retina linked to DS. Lower choroidal vascularity associated with DS.