Abnormal retinal capillary blood flow in autosomal dominant Alzheimer's disease

INTRODUCTION: This study characterizes retinal capillary blood flow in subjects with autosomal dominant Alzheimer's disease (ADAD)‐causing mutations. METHODS: Carriers of PSEN1 or APP mutations were prospectively recruited and split into early‐stage (ES) and late‐stage (LS) groups. Controls were normal subjects and non‐carriers from the at‐risk group. Capillary blood flow was quantified using an optical coherence tomography angiography‐based measure of erythrocyte flux through capillary segments. Statistical analyses were adjusted for correlation between two eyes of the same subject. RESULTS: ES carriers had significantly greater capillary blood flow than controls and LS carriers. ES and LS carriers had significantly greater capillary blood flow heterogeneity than controls. There was no difference between capillary blood flow of LS carriers and controls. DISCUSSION: ES ADAD carriers demonstrate increased retinal capillary blood flow and flow heterogeneity compared to controls. These findings support the hypothesis that increased perfusion is a pathophysiologic feature of presymptomatic stages of ADAD.