Associations Between Glaucoma and Cognitive Function Not Substantial

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Incident glaucoma was associated with higher cognitive function scores but steeper rates of cognitive score decline over time.

A new population-based study from Michigan suggested the associations between glaucoma and cognitive function were “small” and unlikely to be clinically meaningful, with incident glaucoma being associated with higher cognitive function scores but steeper rates of cognitive score decline over time.

Previous studies on these associations have often yielded mix results, but the investigative team led by Ajay Kolli, MD, MPH, of the Department of Ophthalmology & Visual Sciences at the University of Michigan believed their larger, more robust study was able to acturately detail these perceived links between glaucoma and cognitive function.

“To our knowledge, no prior study has provided evidence on whether glaucoma is associated with longitudinal changes in cognitive function in a representative sample,” the authors wrote.

The Health and Retirement Study

Kolli and colleagues utilized data from the Health and Retirement Study (HRS), which was a longitudinal national survey of US adults 51 years and older that began 3 decades earlier. The survey is home to various sociodemographic, health, and economic data, all of which have been collected regularly since 1992.

The current study included data from HRS as well as Medicare claims recorded from 1998 to 2016 from participants 65 years and older at the time of their glaucoma diagnosis.

Patients were featured in the current study if they were enrolled in Medicare Parts A and B for ≥90% of the months during the study period and had completed the Telephone Interview for Cognitive Status (TICS) assessment. Control subjects were also enrolled if they had 1 or more eye exam claims.

Inclusion criteria for glaucoma cases also included ≥2 eye exams by an ophthalmologist or optometrist within 18 months of the index date. In total, the study featured 1344 cases of prevalent glaucoma and 5729 controls, with analyses of incident glaucoma including 886 cases and 4385 controls.

The Findings

Fully adjusted models indicated that participants with prevalent glaucoma had similar TICS scores observed in the control group (P=0.86). However, investigators noticed a statistically significant association between incident glaucoma and lower TICS scores (P=0.007).

Regarding per-year rates of change in TICS scores, investigators observed no significant association between either group, and no significant associations were seen when categorizing glaucoma by type and the levels or rates of change in TICS scores.

Kolli and colleagues cited several “worthy strengths” of their study, including their large sample size and the categorization of participants based on the type of glaucoma they had.

In their concluding remarks, the team suggested that- based on the previously documented association between vision impairment, cognitive decline and dementia, glaucoma-related vision loss could be a risk factor for adverse cognitive outcomes.

“Thus, additional research is needed to determine whether the magnitude of glaucomatous vision loss and/or specific type of visual loss due to glaucoma are associate with cognitive outcomes,” the team wrote.