Relationship of Retinal Nerve Fibers Layer Thickness with Mild Cognitive Impairment and Alzheimer's Dementia

In this study, the thickness of the retinal nerve fibers layer(RNFL) was compared among patients with mild cognitive impairment, Alzheimer's dementia, and healthy individuals (controls) using Optical Coherence Tomography (OCT) device.

This case-control study was conducted on 30 patients diagnosed with mild cognitive impairment and 31 healthy subjects undergoing neurological examination. The examinations included minimal mental state examination a comprehensive assessment of ophthalmology and performance of OCT using a Spectralis device. Both eyes were selected for analysis, and the differences in the thickness of retinal nerve fibers layer between patients with mild cognitive impairment and healthy subjects were investigated.

In this study, the mean age scores of the patients and healthy individuals were 66.00±8.56 and 60.25±7.50 years, respectively. According to the results of the ordinal logistic regression model, after controlling the effects of other variables, the severity of cognitive impairment increased by 1.26 times in the right eye and by 1.30 times in the left eye (P<0.001). Similarly, for each micrometer increase in the thickness of the retinal nerve layer in the superior quadrant of the right and left eyes, the severity of the cognitive impairment decreased by 4% and 5%, respectively.

These results indicated that superior and inferior retinal nerve fiberslayer thickness was reduced in patients with mild cognitive impairment and Alzheimer's dementia, compared to the healthy subjects, and it can be an element to detect and track this pathology.