Lack of association of morphologic and functional retinal changes with motor and non-motor symptoms severity in Parkinson’s disease

Visual symptoms are common among the non-motor symptoms in Parkinson’s disease. The aims of this study were to assess the diagnostic accuracy and relationship of retinal morphologic and functional changes with motor and non-motor symptoms disturbances in Parkinson’s disease. Thirty patients with Parkinson’s disease, with a median Hoehn–Yahr stage of 2 (1–4), were compared to 30 age- and gender-matched controls. Retinal thinning and function were measured using optical coherence tomography (OCT), visual evoked potentials (VEP), and pattern electroretinography. Motor impairment and motor laterality were measured using the Short Parkinson’s Evaluation Scale/Scales for Outcomes in Parkinson’s disease, and non-motor symptoms severity using the non-motor symptoms questionnaire. Only pattern electroretinography, P50 and N95 amplitudes, were lower in patients with Parkinson’s disease, compared to controls (p = 0.01, respectively). Age, disease duration, levodopa dose, motor, and non-motor impairment were not significantly associated with retinal thinning and functional changes. The patients vs. controls area under the curve of OCT, VEP, and pattern electroretinography receiver-operating-characteristic curves were <0.50. In conclusion, morphologic and functional retina changes are not significantly correlated with motor and non-motor symptoms impairment severity, and do not discriminate between Parkinson’s disease and controls.