Higher prevalence of visual symptomatology in individuals with Parkinson’s disease

Abstract

Purpose: We have recently reported that the prevalence of visual symptoms linked with convergence insufficiency (CI) was higher in a group of individuals with Parkinson's disease - PD (27%) compared to those in an age-matched group without PD (9%). Here, we investigated the prevalence of visual symptomatology in individuals with vs without PD who, based on a co-existing oculovisual condition, were excluded from participation in our original study. We hypothesize that the prevalence would be higher in those with PD than those without.

Methods: Two study groups (n= 82 each) were included: 1) participants having PD (Avg. ± SD: 71.2 ± 10.4 yrs) recruited from two specialized neurology departments, and 2) age-matched participants not having PD (70.5 ± 9.2 yrs). These participants had various oculovisual conditions (eg. strabismus, glaucoma) excluding them from the CI study. The Convergence Insufficiency Symptom Survey (CISS-15) was also used here to verify visual symptomatology in the 2 study groups. A score of ≥ 21 is considered positive for symptomatology. The CISS-15 and a detailed oculovisual questionnaire were administered to each participant by a telephone interview. Confidence intervals and t-tests were performed using SPSS.

Results: The participants did not differ for age (p = 0.60). The results indicated that 45.1% of participants with vs 17.1% of those without PD presented a score of ≥21 on the CISS-15 questionnaire (p < 0.05).

Conclusions: We have previously shown that the prevalence of visual symptoms is higher in individuals with vs without PD but without a co-existing oculovisual condition. We demonstrate here that this prevalence remains higher in individuals with vs without PD who also have a co-existing oculovisual condition. These results indicate that PD per se places individuals with the disease at greater risk of visual symptomatology.