Retinal Morphological Changes during the Two Years of Follow-Up in Parkinson's Disease

Abstract Background: The study aims to investigate the relationship between the progression of idiopathic Parkinson's disease (IPD) and retinal morphology. Methods: The study was carried out with 23 patients diagnosed with early-stage IPD (phases 1 and 2 of the Hoehn and Yahr scale) and 30 age-matched healthy controls. All patients were followed up at least two years, with 6-month intervals (initial, 6th month, 12th month, 18th month, and 24th month), and detailed neurological and ophthalmic examinations were performed at each follow-up. Unified Parkinson's Disease Rating Scale part III (UPDRS Part III) scores, Hoehn and Yahr (H&Y) scores, best-corrected visual acuity (BCVA), intraocular pressure (IOP) measurement, central macular thickness (CMT) and retinal nerve fiber layer (RNFL) thickness were analyzed at each visit. Results: The average age of the IPD and control groups was 43.96 ± 4.88 years, 44.53 ± 0.83 years, respectively. The mean duration of the disease in the IPD group was 7.48 ± 5.10 months at the start of the study (range 0-16). There was no statistically significant difference in BCVA and IOP values between the two groups during the two-year follow-up period (p> 0.05, p> 0.05, respectively). Average and superior quadrant RNFL thicknesses were statistically different between the two groups at 24 months and there was no significant difference between other visits (p = 0.025, p=0.034, p> 0.05, respectively). There was no statistically significant difference in CMT between the two groups during the follow-up period (p> 0.05). Conclusion: Average and superior quadrant RNFL thicknesses were significantly thinning with the progression of IPD.