Investigation of the Relationship between Retinal Nerve Fiber Layer Thickness and Mild Cognitive Impairment

This study investigated the difference between patients with mild cognitive impairment and healthy controls using Optical Coherence Tomography (OCT) regarding Retinal Nerve Fiber Layer (RNFL) thickness.

In total, 20 patients with mild cognitive impairment and 20 healthy controls were subjected to neurological examination in this case-control study. The examinations included Minimal Mental State Examination test, comprehensive examination of the eye, and OCT using SPECTRALIS®. The data were analyzed to evaluate the thickness of RFNL through descriptive and analytical statistics. Both eyes were selected for analysis, and the patients with mild cognitive impairment were compared with the healthy controls regarding the RFNL thickness.

The mean age of the patients was 61.4±3.4 years (age range: 53-65 years), and the mean RNFL thickness in patients was 100±10.1 μm. Moreover, the mean values of RNFL thickness in the lower, upper, nasal, and temporal quadrants were 128±18.9, 119±12.2, 87±14.06, and 68±10.3 μm, respectively. There was no difference between females (99±13.2) and males (103±5.6) regarding the RNFL thickness. In addition, no significant difference was observed between the male and female age groups in terms of the RNFL thickness. Additionally, there was no significant difference between the patients (100±10.1) and control group (104±8.7) regarding the RNFL thickness. The chance of developing mild cognitive impairment is increased by 1.45 times with increasing age. It should be noted that this relationship was statistically significant (P<0.001).

The results of this study indicate that patients with mild cognitive impairment had reduced RNFL thickness, compared to healthy controls. However, since this difference was not significant, it cannot be regarded as a proper approach for diagnosis and follow up of the patients.