Prevalence of Convergence Insufficiency-Type Symptomatology in Parkinson’s Disease

Background: Individuals with Parkinson’s disease (PD) often present with visual symptoms (e.g., difficulty in reading, double vision) that can also be found in convergence insufficiency (CI). Our objective was to estimate the prevalence of CI-type visual symptomatology in individuals with PD, in comparison with controls. Methods: Participants ≥50 years with (n=300) and without (n=300) PD were recruited. They were administered the Convergence Insufficiency Symptom Survey (CISS–15) over the phone. A score of ≥21 on the CISS–15, considered positive for CI-type symptomatology, served as the cutoff. Data from individuals (n=87 with, n=94 without PD) who were approached but who reported having a known oculovisual condition were analysed separately. Student’s t test and chi-square at the 0.05 level were employed for statistical significance. Results: A total of 29.3% of participants with versus 7.3% without PD presented with a score of ≥21 on the CISS–15 (p=0.001). Of the participants having a known oculovisual condition, 39.1% with versus 19.1% without PD presented with a score of ≥21 on the CISS–15 (p=0.01). Conclusions: The prevalence of CI-type visual symptoms is higher in individuals with versus without PD whether or not they have a coexisting oculovisual condition. These results suggest that PD per se places individuals with the disease at greater risk of visual symptomatology. These results further underline the importance of providing regular eye exams for individuals with PD. Prévalence de la symptomatologie de type insuffisance de convergence dans la maladie de Parkinson. Contexte : Les symptômes visuels (difficulté à lire, vision double), qu’on retrouve souvent dans l’insuffisance de convergence (IC), sont fréquents chez les patients atteints de la maladie de Parkinson (MP). Notre objectif était d’estimer la prévalence de la symptomatologie visuelle de type IC chez des patients atteints de la MP par rapport à des sujets témoins. Méthodologie : Nous avons recruté des sujets âgés de 50 ans ou plus, avec MP (n=300) et sans MP (n=300). Ils ont répondu par téléphone au questionnaire Convergence Insufficiency Symptom Survey (CISS-15). Un score de 21 ou plus au CISS-15, qui est considéré comme positif pour la symptomatologie de type IC, a été utilisé comme seuil de coupe. Les données des sujets qui ont été contactés et qui rapportaient avoir un problème oculovisuel connu ont été analysées séparément. Nous avons utilisé le test de t de Student et le test du ch