Macular Thickness Decrease in Asymptomatic Subjects at High Genetic Risk of Developing Alzheimer's Disease: An OCT Study.

In this case control study, we examined the retinal thickness of the different layers in the macular region and peripapillary retinal nerve fiber layer (RNFL) with optical coherence tomography (OCT) in healthy cognitive subjects (from 51 to 74 years old) at high genetic risk for developing Alzheimer's disease (AD). Thirty-five subjects with a family history of Alzheimer disease (AD) (FH+) and ApoE ɛ4 carriers and 29 age-matched control subjects without a family history of AD (FH-) and ApoE ɛ4 non-carriers were included. Compared to FH- ApoE ɛ4 non-carriers, in FH+ ApoE ɛ4 carriers, there were statistically significant decreases (p < 0.05) in (i) the foveal area of mRNFL; (ii) the inferior and nasal sectors in the outer and inner macular ring in the inner plexiform layer (IPL); (iii) the foveal area and the inferior sector in the outer macular ring in the inner nuclear layer (INL); and (iv) the inferior sector of the outer macular ring in the outer plexiform layer (OPL). However, no statistically significant differences were found in the peripapillary thickness of RNFL between both study groups. In subjects with cognitive health and high genetic risk for the development of AD, initial changes appeared in the macular area. OCT could be a promising, cost-effective and non-invasive test useful in early AD, before the onset of clinical symptoms.