Longitudinal Analysis of the Retina and Choroid in Cognitively Normal Individuals at Higher Genetic Risk of Alzheimer Disease.

PURPOSE: To assess the baseline differences and longitudinal rate of change in retinal and choroidal imaging parameters between apolipoprotein ε4 (APOE ε4) carriers and noncarriers with normal cognition.

DESIGN

Prospective study.

SUBJECTS: Four hundred thirteen eyes of 218 individuals with normal cognition aged ≥ 55 years with known APOE status (98 APOE ε4 carriers and 120 noncarriers). The exclusion criteria included diabetes mellitus, uncontrolled hypertension, glaucoma, and vitreoretinal or neurodegenerative disease.

METHODS

OCT and OCT angiography (OCTA) were performed at baseline and 2 years (Zeiss Cirrus HD-OCT 5000 with AngioPlex; Zeiss Meditec). The groups were compared using sex- and age-adjusted generalized estimating equations.

MAIN OUTCOME MEASURES: OCT parameters: retinal nerve fiber layer thickness, macular ganglion cell-inner plexiform layer thickness, central subfield thickness (CST), and choroidal vascularity index. OCT angiography parameters: foveal avascular zone area, perfusion density (PD), vessel density, peripapillary capillary PD (CPD), and capillary flux index (CFI). The rate of change per year was calculated.

RESULTS

At the baseline, the APOE ε4 carriers had lower CST (P = 0.018), PD in the 6-mm ETDRS circle (P = 0.049), and temporal CFI (P = 0.047). Seventy-one APOE ε4 carriers and 78 noncarriers returned at 2 years; at follow-up, the 6-mm ETDRS circle (P = 0.05) and outer ring (P = 0.049) showed lower PD in the APOE ε4 carriers, with no differences in the rates of change between the groups (all P > 0.05).

CONCLUSIONS

There was exploratory evidence of differences in the CST, PD, and peripapillary CFI between the APOE ε4 carriers and noncarriers with normal cognition. Larger and longer-term studies may help further elucidate the potential prognostic value of these findings.