Malaysian researchers recently found that patients with cognitive impairment (CI) are more likely to produce unreliable visual field test results with higher false negative responses and a consequent overestimation of the mean deviation.

This prospective cross-sectional study included 113 eyes of 60 glaucoma patients with no prior diagnosis of dementia. The team monitored participants with the Humphrey visual field analyzer using a 30-2 SITA and standard protocol and assessed CI using the clock drawing test . They then analyzed the relationships between the that score, visual field mean and pattern standard deviation, visual field index, fixation loss, false positive value and false negative value.

The researchers found that glaucoma patients older than 65 had a higher prevalence of CI. They note that there was a statistically significant correlation between clock drawing test scores, glaucoma severity and fixation loss, false negative and visual field index values. They add that patients with lower false negatives were significantly less likely to have CI and that patients with higher mean deviation were more likely to have CI, while false positives, fixation loss, pattern standard deviation and visual field index showed no significant correlation.

The study concludes that screening and monitoring for CI may be important in assessing visual field progression in glaucoma patients. 

Raman P, Khy Ching Y, Sivagurunathan PD, et al. The association between visual field reliability indices and cognitive impairment in glaucoma patients. J Glaucoma. April 24, 2019. [Epub ahead of print].