Aim: To investigate the retinal nerve fiber layer (RNFL) thickness in patients with Alzheimer disease (AD) without visual impairment using optical coherence tomography (OCT) and to compare the results with healthy control. Study Design: Case Control, Quantities, non-randomized study. Methods and materials: This study was conducted in the neurology and ophthalmology department, King Faisal Specialized hospital, Riyadh, Saudi Arabia from January 2015 to April 2015. Sample: This study was included 22 participants, 11 Alzheimer's patients and 11 healthy controls between the age of 50-75 years old female and male. Examinations: After sinning the informed consent, a number of examinations in the ophthalmology performed and the retinal nerve fiber layer thickness was measured by 3D OCT-2000 Spectral Domain OCT. Statistical Analysis: All statistical analysis was performed using the Statistical Package for the Social Sciences (SPSS), version 21.0, for MacBook Pro. Data were expressed as mean ± standard deviation. All the data were analyzed and compared using Mann–Whitney U test. A P-value ≤ 0.05 was considered to indicate statistical significance. Results: Patients with AD showed a significant reduction in the total RNFLT compared to the control group (84.21 ± 12.68 μm versus 98.27 ± 16.25 μm; P = 0.006). Furthermore, the nasal and inferior RNFL thickness were significantly lower in patients with AD compared to the controls with a P = 0.007 and P = 0.010 in the nasal and the inferior quadrant, respectively. Also, no significant thinning in the temporal and the superior quadrant in AD retinal nerve fiber layer was detected. Conclusion: Patients with Alzheimer disease exhibit a thinner retinal nerve fiber layer (RNFL) than the healthy control subjects.