Background: Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and memory impairment. Early detection is crucial for timely intervention, and retinal nerve fiber layer (RNFL) thickness, measured using optical coherence tomography (OCT), has been explored as a potential non-invasive biomarker for AD. Objective: This study aims to assess RNFL thickness in AD patients compared to healthy controls and explore the correlation between RNFL thinning and cognitive decline. Methods: A cross-sectional study was conducted with 50 participants: 25 patients diagnosed with AD and 25 age-matched healthy controls. RNFL thickness in the superior, inferior, nasal, and temporal quadrants was measured using Spectral-Domain OCT. Cognitive function was evaluated using the Mini-Mental State Examination (MMSE). Results: AD patients showed significant RNFL thinning in all quadrants compared to controls (p < 0.001). A positive correlation was found between RNFL thickness in the superior (r = 0.42) and inferior (r = 0.37) quadrants and MMSE scores (p < 0.05), suggesting a link between RNFL thinning and cognitive decline. Conclusion: RNFL thinning is significantly associated with Alzheimer's disease and may serve as a non-invasive biomarker for early detection and monitoring of disease progression.