Link Between Systemic Medication and IOP in a British Population
The authors of the population-based, cross-sectional study below sought to determine the association between systemic medication use and intraocular pressure in a population of older British men and women.
They included 7,093 participants from the European Prospective Investigation into the Cancer–Norfolk Eye Study. Exclusion criteria were a history of glaucoma therapy (medical, laser or surgical), IOP asymmetry between eyes of >5 mmHg and missing data for any covariables. The mean age of participants was 68 years (range, 48 to 92) and 56% were women.
The study authors used the Ocular Response Analyzer to measure IOP. They took three readings per eye and considered the best signal value of the Goldmann-correlated IOP value. They asked participants to bring all of their medications and related documentation to the health examination, and these were recorded by the research nurse using an electronic case record form. The medication classes examined were angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, alpha-blockers, beta-blockers, calcium channel blockers, diuretics, nitrates, statins, insulin, biguanides, sulfonylureas, aspirin and other nonsteroidal anti-inflammatory drugs. They authors examined associations between medication use and IOP using multivariable linear regression models adjusted for age, sex and body mass index. Models containing diabetic medication were further adjusted for glycosylated hemoglobin levels. Mean IOP of the right and left eyes were the main outcome measures.
The authors noted that use of systemic beta-blockers (–0.92 mmHg; 95% CI, –1.19, –0.65; p<0.001) and nitrates (–0.63 mmHg; 95% CI, –1.12, –0.14; p=0.011) were independently associated with lower IOP. Additionally, the observed associations between statin or aspirin use with IOP were no longer significant after adjustment for beta-blocker use.
This is the first population-based study to demonstrate and quantify clinically significant differences in IOP among participants using systemic beta-blockers or nitrates. Lower IOP observed in participants using statins or aspirin was explained by concurrent systemic beta-blocker use. The study findings may have implications for the management of glaucoma patients with comorbidity, and may provide insight into the pathophysiologic processes underlying IOP.