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In the first published report on the relationship between mitral valve prolapse (MVP) and open-angle glaucoma (OAG), researchers showed that preexisting MVP is a significant predictor for the development of OAG.1
MVP and OAG exhibit a similar pathophysiology in the mitral valve and the extracellular matrix of the trabecular meshwork: the excessive accumulation of collagen. This can cause myxomatous degeneration of the valve leaflets in the heart; in the eye, it may affect aqueous outflow facility. Thus, author Shuo-Ju Chiang, MD, PhD, a cardiologist at Taipei Medical University, hypothesized that people with MVP would have a higher incidence of OAG.
Sifting through a large database. He and his colleagues searched for correlations in Taiwan’s Longitudinal Health Insurance Database, following 21,677 patients with MVP for 12 years. A comparison group of 86,708 individuals was randomly selected to increase the statistical power. “Our case number was large enough to prove our hypothesis,” said Dr. Chiang.
After adjusting for confounding factors, the researchers found an overall hazard ratio of 1.88 (95 percent CI, 1.58-2.23) for OAG in the MVP group compared with controls.
Study limitations. One potential weakness of the study was the high number of confounding variables, as many conditions may affect OAG. To reduce confounding, the two groups were matched for factors including age, sex, heart disease, cerebrovascular disease, coronary artery disease, hyperlipidemia, hypertension, diabetes, migraine, sleep apnea, and myopia.
However, there were no data on other possible risk factors, such as smoking, race, and body mass index. Further, because MVP is often asymptomatic, it might have been underdiagnosed, masking the true association between MVP and OAG.
Recommendations. Dr. Chiang noted that further studies are needed to confirm these findings and to clarify the underlying mechanism. Meanwhile, he recommended: “The measurement of ocular pressure is needed earlier and more frequently in patients with MVP to achieve early diagnosis and treatment of OAG.”
—Gabrielle Weiner
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1 Chiang SJ et al. Heart. 2014;101(8):609-615.
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Dr. Chiang reports no related financial interests.
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