A study found that calcium channel blockers may be linked to higher glaucoma rates and that beta-blockers may reduce intraocular eye pressure.

Glaucoma is a leading cause of irreversible vision impairment worldwide, with elevated intraocular pressure (IOP) as the only modifiable risk factor for onset and progression. The condition is associated with older age, which also correlates with an increased prevalence of comorbidities and polypharmacy. Patients with glaucoma often have systemic comorbidities, such as hypertension and diabetes, making it important to understand how commonly used systemic medications may affect glaucoma risk and IOP regulation.

Various classes of systemic medications have been implicated in modulating glaucoma risk by impacting optic nerve head perfusion, retinal ganglion cell survival, and aqueous humor outflow. Some studies have reported associations between selective serotonin reuptake inhibitors and reduced glaucoma risk, whereas calcium channel blockers (CCBs) have been linked to an increased risk. Other medications, such as beta-blockers, metformin, statins, and bupropion, have shown varying associations with glaucoma risk and IOP.

Analysis Adjusted for Confounders & Polypharmacy

For a study published in Ophthalmology, Anthony Khawaja, MD, PhD, and colleagues aimed to definitively examine the associations of commonly used systemic medications with glaucoma prevalence and IOP across 11 independent population cohorts, accounting for important confounders and polypharmacy.

The study included participants recruited between 1991 and 2017. Glaucoma diagnosis was ascertained using various methods, including visual field testing, optic nerve head examination, and self-reported data. IOP measurements were obtained using tonometry, and medication data were collected from prescriptions, medication containers, or self-reported questionnaires.

Systemic medications were classified according to the Anatomical Therapeutic Chemical classification system, including antihypertensive medications and lipid-lowering medications. The analysis adjusted for covariables, including age, sex, BMI, diabetes mellitus status, systolic blood pressure, and total cholesterol. “Associations with antidiabetic medications were examined in participants with diabetes only,” wrote Dr. Khawaja and team.

Key Findings on Medications Associated With Glaucoma & IOP

The results revealed several significant associations:

• Calcium channel blockers (CCBs) were associated with a higher prevalence of glaucoma (OR, 1.23; 95% CI, 1.08-1.39), particularly monotherapy of CCBs with direct cardiac effects (OR, 1.96; 95% CI, 1.23-3.12).
• Systemic beta-blockers (beta coefficient, −33 mm Hg; 95% CI, −0.57 to −0.08 mm Hg), including monotherapy of both nonselective (beta coefficient, −0.54 mm Hg; 95% CI, −0.94 to −0.15 mm Hg) and selective (beta coefficient, −0.45 mm Hg; 95% CI −0.74 to −0.16 mm Hg), were associated with lower IOP.
• High-ceiling diuretics showed a suggestive association with lower IOP (beta coefficient, −0.30 mm Hg; 95% CI, −0.47 to −0.14 mm Hg), but this association disappeared after adjusting for other medications and systolic blood pressure.
• Aldosterone antagonist monotherapy tended to be associated with higher IOP (beta coefficient, 1.21 mm Hg; 95% CI, 0.27-2.14 mm Hg).

Other antihypertensive medications, lipid-lowering medications, antidepressants, and antidiabetic medications did not show significant associations with glaucoma prevalence or IOP.

The findings regarding CCBs and glaucoma risk are consistent with previous research. The study suggests that CCB use may increase the prevalence of glaucoma. However, it is essential to note that this study does not establish causation, and further research is needed to confirm these associations.

The association between systemic beta-blockers and lower IOP is also consistent with previous studies. It is worth noting that while lower IOP is generally associated with a reduced risk of glaucoma, the study did not find a significant association between systemic beta-blocker use and glaucoma prevalence. This could be due to the complex interplay between blood pressure, IOP, and glaucoma development.

Implications in Practice

These findings can be relevant for healthcare providers managing patients with glaucoma and comorbidities, as they may need to consider the potential effects of systemic medications on glaucoma risk and IOP control. They are “important, given that patients with glaucoma frequently use systemic antihypertensive medications,” wrote the study team. “Determining causality of the CCB association should be a research priority.”