Fig. 1From: Towards seeing the visual impairments in Parkinson’s disease: protocol for a multicentre observational, cross-sectional studyFlowchart of the study design. Here we present our two-phase study. In phase 1, at least 750 PD patients and 250 healthy controls will complete the Visual impairment in Parkinson’s Disease Questionnaire (VIPD-Q). In phase 2, a subgroup of responders (n = 100) will be invited for an extensive neurological and ophthalmological assessmentBack to article page