Prevalence and Risk Factors for Double Vision in Parkinson Disease

Background: Some patients with Parkinson Disease (PD) report double vision, but its prevalence and determinants are unknown. Objectives: To determine the prevalence and risk factors for diplopia in PD. Methods: Using data from 26,790 PD patients and 9257 controls in the Fox Insight Study, we compared the prevalence of diplopia using the Non-Movement Symptom Questionnaire. Associations with age, race, gender, disease duration, and scores on MDS-UPDRS part II, and Penn Parkinson's Daily Activity Questionnaire were assessed with generalized estimating equations. Results: The point prevalence of diplopia was higher in PD (18.1%) than controls (6.3%, P < 0.001) at baseline, and 28.2% of all PD patients reported diplopia at least once during the study (period prevalence). PD patients with diplopia were more likely to be older, non-white, have greater disease duration, and report greater motor, non-motor, and daily activity limitations. Conclusions: Diplopia is common and associates with motor and non-motor severity in PD.