Structural and Functional Impairment of the Retina and Optic Nerve in Alzheimer’s Disease

Abstract

PURPOSE: The purpose of this study was to evaluate the macular and retinal nerve fiber layer (RNFL) thickness, and the electrical activity of the macula in patients with Alzheimer's disease (AD). MATERIAL AND METHODS: 30 patients with AD and 30 age and sex matched healthy controls were studied. The thickness and the electrical activity of the macula were evaluated by means of optical coherence tomography (OCT) and multifocal-electroretinogram (mf-ERG). RESULTS: Visual acuity, as well as visual fields and colour vision testing of all patients were normal. However, the mean foveal thickness was 148.50 μm (vs. 171.50 μm in the control group, p=0.001) and the RNFL thickness was 104.5 μm in the superior area (vs 123 μm in the control group, p < 0.0001) and 116.5 μm in the inferior area (vs. 138 μm in the control group, p < 0.0001) around the optic nerve. The mean P1 response density amplitude of the foveal area was 146.50 nV/deg2 (vs. 293 nV/deg2 in the control group, p < 0.0001) and the perifoveal area was 56.60 nV/deg2 (vs. 81.50 nv/deg2 in the control group, p < 0.001). CONCLUSION: Our study showed that in patients with AD, even without visual failure there was a decrease in macular and RNFL thickness, as well as a decrease of the electrical activity of the macula.