Background: Dementia is a neurodegenerative disorder characterized by progressive cognitive decline. Retinal nerve fiber layer (RNFL) thickness, as measured by spectral domain optical coherence tomography (SD-OCT), has been investigated as a potential biomarker for neurodegeneration. Objective: This study aims to measure and analyze RNFL thickness in dementia patients using SD-OCT, compare it with normal values, and correlate it with the Mini-Mental State Examination (MMSE) score. Methods: A cross-sectional study was conducted over three months on 36 dementia patients aged above 18 years attending the ophthalmology outpatient department. Patients underwent comprehensive ocular examinations, including visual acuity assessment, intraocular pressure (IOP) measurement, slit-lamp examination, fundus examination, and SD-OCT imaging. RNFL thickness in different quadrants (superior, inferior, nasal, and temporal) was measured and compared with established normative data. The correlation between RNFL thickness and MMSE scores was analyzed. Results: The mean global RNFL thickness in dementia patients was 78.2 ± 8.5 µm, which was significantly lower than the normal reference range (92.4 ± 9.2 µm, p < 0.001). The superior and inferior quadrants showed the greatest reduction in RNFL thickness (Superior: 92.1 ± 8.3 µm vs. 108.5 ± 9.7 µm, p < 0.001; Inferior: 95.6 ± 9.1 µm vs. 112.2 ± 8.5 µm, p < 0.001). Temporal and nasal quadrants were less affected. A significant positive correlation was found between MMSE scores and RNFL thickness (r = 0.52, p = 0.002). Conclusion: Dementia patients exhibit significant thinning of the RNFL, particularly in the superior and inferior quadrants. RNFL thickness correlates with cognitive decline as measured by MMSE, supporting its potential as a non-invasive biomarker for neurodegeneration in dementia. Further longitudinal studies with larger cohorts are warranted.

Retinal Nerve Fiber Layer (RNFL), Spectral-Domain OCT (SD-OCT), Alzheimer’s Disease (AD), Neurodegeneration, Retinal Biomarkers, Cognitive Decline, Mini-Mental State Examination (MMSE), Neurodegenerative Biomarker, RNFL Thinning in Neurodegeneration