Analysis of changes in the macula and retinal nerve fiber layer by optical coherence tomography in patients with Alzheimer’s disease (AD)

Purpose To evaluate the usefulness of optical coherence tomography (OCT) in the diagnosis of Alzheimer’s disease(AD) Thickness is determined at the peripapillary RNFL and macular volume with OCT, in individuals suffering from AD and compared with a control group. Methods Prospective study in 40 eyes of 20 patients with Alzheimer’s disease and 40 eyes of 20 controls, measuring the thickness of the peripapillary RNFL and macular volume with OCT. Results The average thickness of RNFL in patients with Alzheimer’s disease was 65,28±11,55 microns (53,50 to 87,29), significantly decreased compared to control subjects, which was 107.1 ± 7, 2 microns (94.9 -128.8) (p = 0.0001. Mann-Whitney U test.). Macular volume in patients with AD was 5.6 ± 0.3 mm 3 compared with control subjects: 7.0 ± 0.5 mm3. Peripapillary RNFL thickness evaluated in each of the separate quadrants (superior, inferior, nasal and temporal) is also statistically significantly decreased in patients with AD in connection with control subjects. However, the central foveal thickness (1 mm), thickness macular inner ring (3 mm) and macular volume were significantly higher in AD patients. Conclusion The AD is the major cause of dementia in the world. Although the entorhinal cortex and hippocampal complex are best known as the sites of early pathology in AD, increasing evidence shows that the eye, particularly the retina, is also affected. The AD-related changes in the retina are associated with degeneration and loss of neurons, reduction of the retinal nerve fibres, increase in optic disc cupping, retinal vascular tortusity and thinning, and visual functional impairment.