Prevalence and Risk Factors for Double Vision in Parkinson Disease

Abstract

BackgroundBackground: Some patients with Parkinson Disease (PD) report double vision, but its prevalence and determinants are unknown. Objectives Objectives: To determine the prevalence and risk factors for diplopia in PD. Methods 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. ResultsResults: 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 Conclusions: Diplopia is common and associates with motor and non-motor severity in PD.Visual dysfunction is a non-motor symptom of Parkinson disease (PD). 1 One of the most common and distressing visual symptoms of PD is double vision, which is caused by convergence insufficiency and other patterns of acquired strabismus and has been postulated to reflect brainstem PD pathology affecting supranuclear gaze-holding structures. 2 However, the prevalence of diplopia in PD is unknown. Studies have reported diplopia in anywhere from 10% to 30% of PD patients, 1,3-8 but these wideranging estimates are based on small studies of patients recruited from tertiary movement disorders or neuro-ophthalmology clinics, which may be biased towards greater disease severity and are likely not reflective of the general PD population. Clinicbased cohorts are also prone to under-ascertainment, as neurologists may not be comfortable addressing visual symptoms, and patients frequently do not disclose non-motor symptoms such as double vision unless specifically asked. 9 As diplopia can also occur in individuals without PD, it is also unclear whether the prevalence of diplopia in PD is greater than expected for age and other comorbidities or whether the increased burden is an artifact of increased health care utilization. Because diplopia is easily treatable with prisms, characterizing the burden and risk factors in PD is essential for developing screening and treatment guidelines. In this study, we examine the prevalence and risk factors for diplopia in a longitudinal survey of more than 25,000 PD patients.

Diplopia Is Frequent and Associated with Motor and Non-Motor Severity in Parkinson’s Disease: Results from the COPPADIS Cohort at 2-Year Follow-Up

“…Schindlbeck et al [ 3 ] detected binocular diplopia in 37 out of 125 PD patients (29.6%) who were screened for diplopia, visual hallucinations, problems with spatial perception, contrast sensitivity, presence of blurred vision, and history of ophthalmological comorbidities via interview. In a more recent longitudinal study, Hamedani et al [ 8 ] reported a point prevalence diplopia of 18.1% in 26,790 PD patients and 6.3% in a control group, being present at least once in up to 28.2% of all the patients during the study (period prevalence). In our cohort, diplopia for each transversal analysis ranged from 13.6% to 17.1% in the patients and was very low in the controls.…”

“…Moreover, the NMSS is useful for detecting not only the presence of a symptom, such as the NMS-Quest [ 17 ], but the frequency and severity as well, being correct to separate the patients as those without the symptom (score = 0) versus those with the symptom (score ≥ 1). In the largest study to date to detect diplopia in PD, the NMSQuest was used, being present in 28.2% of all the PD patients compared to 9.1% of controls [ 8 ]. Using the NMSS with our methodology (only one visit), Martinez-Martin et al, identified 72 out of 411 (17.5%) patients as PD patients with double vision [ 18 ].…”

“…This finding suggests that asking about diplopia could be a simple clinical marker informing us of the possible condition of the patient, regardless of age and disease duration time, which is important in PD given the great variability in clinical presentation, from mild but long-term cases to very severe cases significantly affected from the beginning. The factors previously associated with diplopia are to be older, to be non-white, to have a longer disease duration, to have greater motor, non-motor, and daily activity limitations, to have visual hallucinations, to have cognitive decline, and to have a higher LEDD [ 3 , 8 ]. We found visual hallucinations as a symptom associated with diplopia in our cohort.…”

“…Diplopia is relatively common in PD but is still understudied [ 2 ]. Its prevalence in PD ranges from 10% to 30% and is usually limited to specific situations, such as reading and looking around [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. A recent review concluded that diplopia in PD patients is usually intermittent and binocular, and the review also identified an older age, a longer disease duration, a greater disease severity, a cognitive decline, a presence of visual hallucinations, and a higher levodopa equivalent daily dose (LEDD) as risk factors contributing to it [ 4 ].…”

“…Very recently, Hamedani et al found, using data from 26,790 PD patients and 9257 controls in the Fox Insight Study, that 28.2% of all the PD patients reported diplopia at least once during the study (period prevalence) and identified to be older, to be non-white, to have a longer disease duration, and to have greater motor, non-motor, and daily activity limitations as factors associated with diplopia. Despite diplopia being frequent in PD, it is under-recognized [ 8 ]. On the other hand, since it is easy to identify by asking the patient, diplopia could be considered as a simple clinical marker of disease severity.…”