Low blood pressure may also be a risk factor for glaucoma. Experts caution against overtreatment of hypertension. Photo: James L. Fanelli, OD. Click image to enlarge.

Glaucoma pathogenesis remains murky, particularly when it comes to the interwoven relationship of blood pressure and antihypertensives and their effects on the disease. To study whether antihypertensive medications may be a potential modifiable risk factor for open-angle glaucoma, researchers examined their effects in patients with hypertension. They found a small increase in the risk for open-angle glaucoma.

The study, published recently in Nature Scientific Reports, included 5,195 patients diagnosed with hypertension and subsequently diagnosed with open-angle glaucoma and 25,975 controls matched for diagnosis date, residential area, insurance type and economic status. The researchers found that after adjusting for age, sex, BMI, lifestyle, comorbidities, blood pressure, follow-up duration and use of other antihypertensives, angiotensin receptor blockers and calcium channel blockers slightly increased the risk of open-angle glaucoma. They also found that combinations of angiotensin receptor blockers with diuretics and calcium channel blockers also increased risks.

“Although the results were statistically significant, the risks mediated by antihypertensive medications in hypertension patients were relatively small as indicated by low odds ratios,” the researchers wrote in their Nature paper.

Ultimately, the mechanisms of medications’ effects on glaucoma pathogenesis remain unclear and require individual study. The researchers pointed out that despite attempts at controlling for confounders, many still exist, such as cardiovascular comorbidities, blood pressure levels and hypertension severity—and use of certain drugs may merely be an indication of an existing comorbidity which on its own could raise the risk of glaucoma, regardless of the antihypertensive drug.

“It is likely that if there is to be any causal relationship between antihypertensive medication and open angle-glaucoma, the open-angle glaucoma risks conferred by medications are generally small and not affected by ongoing, long-term use,” they wrote.