Normal-tension glaucoma is associated with cognitive impairment

Abstract

Background/aims: Recent research suggests an association between normal-tension glaucoma (NTG) and dementia. This study investigated whether cognitive impairment is more strongly associated with NTG than high tension glaucoma (HTG) using cognitive screening within an Australiasian Glaucoma Disease Registry.

Methods: The authors completed a case-control cross-sectional cognitive screening involving 290 age-matched and sex-matched NTG participants and HTG controls aged ≥65 randomly sampled from the Australian and New Zealand Registry of Advanced Glaucoma. Cognitive screening was performed using the Telephone Version of the Montreal Cognitive Assessment (T-MoCA). The T-MoCA omits points requiring visual interpretation, accounting for confounding factors related to vision loss in visually impaired participants. Cognitive impairment was defined by a T-MoCA score of <11/22. Cognition was compared between NTG and HTG participants using predetermined thresholds and absolute screening scores.

Results: A total of 290 participants completed cognitive assessment. There were no differences in NTG (n=144) and HTG (n=146) cohort demographics or ocular parameters at baseline. Cognitive impairment was more prevalent in the NTG cohort than the HTG cohort (OR=2.2; 95% CI 1.1 to 6.7, p=0.030). Though a linear trend was also observed between lower absolute T-MoCA scores in the NTG cohort when compared with the HTG cohort, this association was not statistically significant (p=0.108).

Conclusion: This study demonstrated an association between NTG status and poor cognition, supporting the hypothesis that there exists a disease association and shared pathoaetiological features between NTG and dementia.

Keywords: degeneration; epidemiology; glaucoma; intraocular pressure.

Figure 1

Sample response profile. ANZRAG, Australian and New Zealand Registry of Advanced Glaucoma; HTG, high tension glaucoma (maximum intraocular pressure ≥25 mm Hg); NTG, normal-tension glaucoma (maximum recorded intraocular pressure ≤21 mm Hg); POAG, primary open-angle glaucoma.