Changes of the Retinal Nerve Fiber Layer in Patients with Mild Cognitive Impairment and Alzheimer's Disease

Background: Alzheimer's disease (AD) is the most common type of dementia and are often associated with visual disorders. Mild cognitive impairment (MCI) is characterized by an impaired memory when compared with people of similar age and education level which indicates an earlier on set of AD. The aim of this study is to measure the retinal nerve fiber layer (RNFL) thickness of AD and MCI patients comparing with the normal age controls. Methods: The retinal nerve fiber layer (RNFL) thickness was assessed with optical coherence tomography (OCT) in patients with MCI, AD (mild, moderate and severe) and also in the corresponding age matched controls. Results: The thicknesses of RNFL are gradually and significantly decreased from MCI to severe AD in the superior quadrant and total mean values when compared to that in the controls. It is also observed that there is a significant reduction of the retinal nerve fiber layer thickness in the inferior quadrant in severe AD patients. Conclusions: Our data shows that the retinal nerve fiber layer degeneration occurs in parallel with progression of dementia. Owing to its cost effective and non - invasive nature, monitoring RNFL thickness is essential in assessing progression of disease and the efficacy of management.