| Abstract: |
The aim of this study is to compare macular retinal layers and choroidal thicknesses of patients with Alzheimer’s disease (AD) with those of patients without other known ophthalmological pathology, using spectral domain optical coherence tomography. Multiple linear regression analysis was applied to assess the effects of age, gender, spherical equivalent, visual acuity, intraocular pressure, axial length and mean arterial pressure on macular retinal layers thickness. Fifty eyes of 50 patients (mean age 73.10; SD=5.36 years) with a diagnosis of mild AD and 152 eyes of 152 patients without AD (mean age 71.03; SD=4.62 years) were included. There was a thinning in the peripheral ring of the ganglion cell layer (GCL) in the AD group (S6 p < 0.001; T6 and N6 p = 0.001). In the superior sectors of the inner plexiform layer (IPL), differences between the two groups also remained statistically significant after Bonferroni correction (S3 p = 0.001 and S6 p < 0.001). In the outer layers we did not observe differences statistically significant for AD group. These layers’ thicknesses were associated with statistical significance with gender (in inner and outer nuclear layers), age and choroidal thickness (CT) (in photoreceptor layer). In the AD patients group, CT was significantly thinner than in the first group of patients without AD, in all 13 locations (p<0.001), and age was relevant factor. Patients with AD showed a significant reduction in retinal layers and choroidal thickness. The thinnest macular measurements were found mostly in the inner layers, GCL and IPL, at superior sectors (pericentral and peripheral rings). This thinning may reflect a retinal characteristic of AD, related with both primary retinal lesion and transsynaptic retrograde degeneration and the choroidal thinning probably reflects the importance of vascular factors in the pathogenesis of this disease. |