Assessment of macular thickness changes by OCT in asymptomatic relatives of Alzheimer’s disease patients

Abstract

Purpose : Alzheimer’s diseases is a neurodegenerative disease, whose pathophysiological features show decades before the main cognitive symptoms appear. In addition to age, genetic factors are one of the most important risk factors.
The aim of the present study was to analyze the retinal thickness changes by optical coherence tomography (OCT) in first-degree relatives of Alzheimer’s disease patients who are carriers of ε4 allele for the ApoE, which are two of the main risk factors for developing the disease.

Methods : Sixty- four participants, who were free of ocular pathology were analyzed. A complete eye examination and OCT were performed. The two study groups were formed by 35 subjects with a family history of AD (FH+) and ApoE ε4 carriers and 29 age-matched control subjects without a family history of AD (FH-) and ApoE ε4 non-carriers.

Results : In FH+ ApoE ε4 carriers compared to FH- ApoE ε4 non-carriers we found a statistical significant thinning (p<0.05) in the next sectors and layers: the foveal area of the macular retinal nerve fiber layer (11.89 ± 1.95,FH+ vs 12.86±1.62,FH-); the inferior and nasal sectors, both in the outer (26.77±2.74,FH+ vs 28.17±2.82,FH- for inferior)(29.49±2.89,FH+ vs 30.93±3.85,FH- for nasal) and inner (40.49±2.51,FH+ vs 42.10±3.48,FH- for inferior) (41.94±2.74,FH+ vs 43.52±3.57, FH- for nasal) macular ring in the inner plexiform layer; the foveal area (18.82±3.61, FH+ vs 21.21±3.88,FH-) and the inferior sector in the outer macular ring (30.91±2.72,FH+ vs 32.10±2.81,FH-) in inner nuclear layer, and the inferior sector of the outer macular ring (27.60±2.75,FH+ vs 29.97±3.82,FH-) in outer plexiform layer. No statistically significant differences were found in the peripapillary thickness of RNFL between both study groups.

Conclusions : In asymptomatic relatives of Alzheimer’s disease patients with high genetic risk for the development of AD, initial changes appeared in the macular area. These slight retinal thickness changes measured by OCT could be used as an early biomarker of the disease.

This is a 2021 ARVO Annual Meeting abstract.