Optical Coherence Tomography Findings in Parkinson's and Alzheimer's Disease -Retinal Changes in Neurodegenerative Disease.

Abstract

To investigate retinal nerve fiber layer (RNFL), macular, foveal and parafoveal thickness in patient with early stage Parkinson's (PD) and Alzheimer's disease (AD) by optical coherence tomography (OCT) and to compare results with healthy control group and between both disease. Participants with AD dementia (n: 15) and PD (n: 15), besides 15 age-sex matched controls were enrolled in the study and received OCT assessments. Clinical disability grade in PD was determined by the Unified Parkinson's Disease Rating Scale and Hoehn Yahr (H-Y) Scale was used to determine the stage of PD. Standardized Mini Mental Test (SMMT) and Montreal Cognitive Rating Scale (MOCA) were used for neurocognitive evaluation of patients with AD. The relationship between OCT and test results was analyzed. OCT measurements did show significant decrease in temporal, nasal, inferiorR (R means examination of retina in two sections as superior and inferior instead of four quadrants) RNFL thickness and foveal, parafoveal, macular thickness of AD group compared to control group. Temporal, inferior and inferiorR RNFL thickness were thinner in patients with PD than those of control group but these differences were not significant. However the superiorR and superior RNFL thickness decreased significantly in the PD group as the disease duration increased. There was no relationship between SMMT, MOCA, UPDRS, H-Y scores and OCT results. As several studies have reported different results so far, we thought that the use of OCT in early diagnosis and follow-up of the course of both diseases was not appropriate until many studies indicated the same result.