Medication Linked With Glaucoma

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Calcium channel blocker use is associated with glaucoma, according to researchers from the U.K.’s National Institute for Health and Care Research’s Biomedical Research Centre, in London, and colleagues. The scientists found that people who used calcium channel blockers—commonly prescribed for hypertension—had, on average, 39% higher odds of glaucoma compared with people who did not take them.¹

Calcium channel blocker use was also associated with thinner macular retinal nerve fiber layer (mRNFL) and macular ganglion cell–inner plexiform layer (mGCIPL)—both objective, structural glaucoma-related parame­ters. There was no link found between calcium channel blocker use and IOP.

The cross-sectional study findings suggest that calcium channel blockers may represent a modifiable risk factor for glaucoma, the authors wrote.

PILL CHECK. Hypertension drugs are associated with glaucoma, according to a new study.

Study details. For their investigation, the scientists analyzed data drawn from 427,480 patient records from the UK Biobank with an ICD code for open-angle or other form of glaucoma. Of these participants, 41,023 had macular spectral-domain OCT imaging and 97,100 had IOP findings. The median age of participants whose records were analyzed was 58, 54% were women, 94.8% were White, and 7.8% used cal­cium channel blockers. The researchers adjusted for various factors including sociodemographic, lifestyle, medical, and other factors. They reported that dihy­dropyridines, the class of calcium channel blockers that includes amlodipine, were the most commonly used subtype (88.4%), fol­lowed by benzothiazepines (9.1%). Both medications were associated with higher odds of glaucoma, but not of elevated IOP.

The researchers’ analysis of OCT-derived inner retinal layer thicknesses also supports the associa­tion between calcium channel blocker use and glaucoma. OCT data revealed that calcium channel blockers were linked to thinner mRNFL thickness (–0.16 μm) and thin ner mGCIPL thick­ness (–0.34 μm) compared with nonus­ers. Dihydropyridine use in particular was associated with thinner mRNFL and mGCIPL. This finding runs counter to some previous research that suggests calcium channel blockers are neuro­protective, said lead study author Alan Kastner, MD, MSc, at the Clínica Oftal­mología Pasteur, in Santiago, Chile.

No associations were found with other classes of antihypertensive agents and glaucoma, including diuretics, renin-angiotensin system inhibitors, and systemic beta-blockers. Dr. Kastner said additional analysis of IOP data from close to 100,000 participants revealed no link between calcium channel block­er use and IOP, suggesting that other IOP-independent mechanisms of glau­comatous neurodegeneration may be involved. “These mechanisms may be related to the effects of calcium channel blockers on the vasculature of the optic nerve head,” he said.

Reflections on the research. In an accompanying editorial, Paula Anne Newman-Casey, MD, MS, and Rith­ambara Ramachandran, MD, at the University of Michigan, Ann Arbor, noted the debate over the use of cal­cium channel blockers as a potential treatment for normal-tension glauco­ma. They also pointed to contradictory evidence over calcium channel block­ers’ impact on IOP and open-angle glaucoma. They wrote that analyses of data from publicly funded and publicly available datasets, like the UK Biobank, can provide critical new information as aging global and U.S. demographics lead to rising glaucoma cases—helping ophthalmologists better understand the unintended consequences to eye health of prescription medicines taken by peo­ple with multiple chronic conditions.²

Are Rx changes needed? The adverse association of calcium channel blockers with glaucoma should not affect care for most patients, Dr. Kastner said. “However, for patients whose glaucoma is worsening despite a very low IOP, we need to think about other factors playing a role. If those patients are on calcium channel blockers, ophthalmologists should discuss the evidence of our study with them and with their general physician and consider changing their antihypertensives.”

—Miriam Karmel

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1 Kastner A et al. JAMA Ophthalmol. 2023;141(10):956-964.

2 Newman-Casey PA, Ramachandran R. JAMA Ophthalmol. 2023;141(10):964-965.

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Relevant financial disclosures: Dr. Kastner—None.

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