Association between Primary Open-Angle Glaucoma and Cognitive Impairment as Measured by the Montreal Cognitive Assessment

Background: It is currently unclear whether primary open-angle glaucoma (POAG) affects neurological functions outside of vision, such as cognition.

Objective: This study examined the association between POAG and cognitive impairment in African Americans.

Methods: Masked interviewers administered the Montreal Cognitive Assessment (MoCA) to patients enrolled in the Primary Open-Angle African American Glaucoma Genetics (POAAGG) study at the Scheie Eye Institute. Cases were further assessed for retinal nerve fiber layer (RNFL) thickness and visual field (VF) loss. Univariate and multivariate linear regression analyses were performed to compare mean MoCA score between cases and controls and to assess the association between POAG severity and MoCA score.

Results: A total of 137 patients completed the MoCA, including 70 cases and 67 controls. The mean age ± SD was 68.7 ± 11.2 years for cases and 65.7 ± 10.4 years for controls (p = 0.11). The mean MoCA total score (out of 30 points) was 20.3 among POAG cases and 21.3 among controls (mean difference = -1.03, 95% confidence interval, CI = -2.54 to 0.48, p = 0.18). After adjusting for age, gender, education level, diabetes, hypertension, and smoking status, the mean difference in the MoCA total score between cases and controls was -0.64 (95% CI = -1.72 to 0.45, p = 0.25). Among cases, more VF loss was associated with lower total MoCA score for mean deviation (adjusted linear trend p = 0.02) and VF index (adjusted linear trend p = 0.03). There was no significant association between average RNFL thickness and total MoCA score.

Conclusions: POAG cases and controls had similar neurocognitive function as measured by the MoCA. Among POAG cases, worse VF loss was associated with lower MoCA. Future studies are needed to further elucidate the clinical effect of neuropathy in POAG.