Visual dysfunction and its correlation with retinal changes in patients with Alzheimer's disease

Aim To evaluate visual dysfunction and its correlation with structural changes in the retina in patients with Alzheimer's disease (AD). Methods Patients with AD (n= 24) and controls (n= 24) underwent evaluation of visual acuity (VA), color vision (using the Farnsworth and L'Anthony desaturated (D) 15 color tests), and contrast sensitivity vision (CSV; using the Pelli-Robson chart and CSV-1000E test) to measure visual dysfunction. Structural measurements of the retinal nerve fiber layer (RNFL) and macular thickness were obtained using spectral domain-optical coherence tomography (SD-OCT). Results CSV at three of the four spatial frequencies was significantly worse in AD patients than in controls. Color vision was significantly affected in AD patients based on the Farnsworth color test. Compared with controls, macular thinning was detected in all sectors except the fovea, and the RNFL exhibited significant thinning in the superior quadrant and lower average thickness (P<0.05). CSV was the functional parameter most strongly correlated with structural measurements in patients with AD. Color vision was strongly associated with macular volume (r>0.70, P<0.05). VA at different levels of contrast was associated with macular and RNFL thickness. Conclusions Patients with AD had visual dysfunction that correlated with structural changes evaluated by SD-OCT. Macular measurements may be reliable indicators of visual impairment in AD patients.