Study subjects were clinically diagnosed Idiopathic Parkinson’s Disease attending Neurology Department, King George Hospital, Visakhapatnam,  India. Similar age-matched consenting controls were also selected. Written and informed consent was obtained from the patients and controls. Clinical severity of patients was graded using UPDRS scale. RNFL thickness of patients and controls was measured using OCT. Correlation statistics were used to measure the association between the duration of the disease and RNFL thickness measures.  Independent sample T test was used to find the statistical difference.

Subjects were  composed of fourty seven   PD patients and  age-matched controls. Among the patients, 57.4% were males, and 42.6%  were females. Among the controls, 30 were males  and 17 were females. Mean age of patients was 65.1 ± 10.7 years and of controls was 64.7 + 9.8. Mean PD duration was 4.7 ± 2.3 years. 59.6% of the sample were of  mild PD, 27.2% were  moderate, and 13.2% were classified as severe. Compared with healthy age-matched controls, the RNFL thickness of patients was much thinner (p=0.031) in all retinal quadrants. The RNFL thickness was negatively correlated with duration of the disease (r= -0.702, p<0.05) and also the severity of disease assessed by UPDRS.

There is reduced thickness of the retinal nerve fiber layer in patients of Idiopathic Parkinson’s Disease compared to the controls. This decrease in thickness correlated with the severity of disease.