Changes in the structure and function of the visual pathway in subjects at high risk for the development of Alzheimer's disease: 27 months of follow‐up

Abstract

Aims/Purpose: In addition to advanced age, two of the most important risk factors for the development of Alzheimer's disease are having a family history of the disease (FH+) and being a carrier of at least one Ɛ4+ allele for the ApoE gene (ApoE Ɛ4+). AD generates changes in the retina and visual function when the disease is established, so the aim of the present work is to know if these changes appear in healthy subjects but with high genetic risk to develop the disease and to analyse if these changes evolve along 27 months of follow‐up.Methods: A retinal thickness analysis by optical coherence tomography and visual function by assessing visual acuity (VA), contrast sensitivity (CS), colour perception, perception digital test and visual field analysis was completed by all participants. For structural findings analysis subjects were divided into (FH+ ApoE Ɛ4+) and (FH‐ ApoE Ɛ4‐) groups and for functional analysis these subgroups were subdivided by ages between 40 and 60 years and subjects over 60 years.Results: After 27 months of follow‐up, the FH+ ApoE Ɛ4+ group experienced changes in the thickness of all retinal layers except the outer layers. In this group, the inner nuclear layer showed progressing changes, but there was no progression in visual function. However, compared to the FH‐ ApoE Ɛ4‐ group at 27 months, the improvement in visual acuity and contrast sensitivity (3 and 12 cpd) observed during the initial visit was maintained.Conclusions: In cognitively healthy individuals at high risk of developing AD structural changes in the retina continue to progress after 27 months, while functional changes detected at the beginning remain stable.