Some High Blood Pressure Drugs May be Associated with Increased Risk of Vision-Threatening Disease

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SAN FRANCISCO, May 28, 2014 /PRNewswire-USNewswire/ -- There may be a connection between taking vasodilators and developing early-stage age-related macular degeneration (AMD), the leading cause of vision loss and blindness among Americans who are age 65 and older,[1] according to a study published online in Ophthalmology, the journal of the American Academy of Ophthalmology.

AMD – the deterioration of the eye's macula, which is responsible for the ability to see fine details clearly – affects an estimated 11 million people in the United States.[2] In addition to increased age, the cause of AMD may be attributed to several risk factors, including hereditary risk and smoking. Some studies have also found an association between AMD and high blood pressure, but this has been inconsistent. To help clarify the relationship between AMD incidence and blood pressure lowering medications, including vasodilators, researchers from the University of Wisconsin School of Medicine and Public Health conducted a long-term population-based cohort study from 1988 to 2013 of nearly 5,000 residents of Beaver Dam, Wis., aged 43 to 86 years. The research is part of the National Eye Institute -funded Beaver Dam Eye Study, which has since 1987 collected information on the prevalence and incidence of AMD, macular degeneration and diabetic retinopathy.

The researchers found that, after adjusting for age, sex and other factors, using any vasodilator such as Apresoline and Loniten, which open (dilate) the blood vessels – was associated with a 72 percent greater risk of developing early-stage AMD. Among people who were not taking vasodilators, an estimated 8.2 percent developed signs of early AMD. In comparison, among those taking a vasodilator medication, 19.1 percent developed the disease.

The researchers also found that taking oral beta blockers such as Tenormin and Lopressor was associated with a 71 percent increase in the risk of neovascular AMD, a more advanced and vision-threatening form of the disease. Among those who were not taking oral beta blockers an estimated 0.5 percent developed signs of neovascular AMD. In comparison among those taking oral beta blockers, 1.2 percent developed neovascular AMD.

While the study provides risk estimates of associations between blood pressure lowering medications and AMD at various stages, the researchers caution that their study was not able to discern effects of the medications themselves and the conditions for which participants were taking those medications.

"As significant as these results may be, it's important that they be replicated first, and if possible tested in a clinical trials setting before changing anyone's medication regimens," said Ronald Klein, M.D., MPH, lead researcher of the study. "Further research is needed to determine the cause of these increased risks."

For more information about AMD and general eye health, visit the American Academy of Ophthalmology's public education website at www.geteyesmart.org.

The May 2014 issue of Ophthalmology, in print now, features a number of new research reports, including:

• The Neovascular Age-Related Macular Degeneration Database: Multicenter Study of 92,976 Ranibizumab Injections: Report 1 – Visual Acuity. This study showed that a well-designed electronic medical record system rapidly produces large volumes of high-quality real-world outcome data to model predictors of vision and treatment burden and to facilitate phase 4 and 5 clinical trial designs.
• Qualitative and Quantitative Characteristics of Near-Infared Autofluorescence in Diabetic Macular Edema. A mosaic pattern seen on near-infrared autofluorescence images is related to macular thickening, photoreceptor damage, and visual impairment, and eyes with hypofluorescence had increased macular thickness and serous retinal detachment in diabetic macular edema.
• Use of Health Care Claims Data to Study Patients with Ophthalmologic Conditions. Analyses of claims data are potentially valuable in examining specific research questions, but these analyses can vary in their methodological rigor. Common advantages and issues are described, and guidance is given for readers to interpret studies properly.

About the American Academy of Ophthalmology
The American Academy of Ophthalmology, headquartered in San Francisco, is the world's largest association of eye physicians and surgeons — Eye M.D.s — with more than 32,000 members worldwide. Eye health care is provided by the three "O's" – ophthalmologists, optometrists, and opticians. It is the ophthalmologist, or Eye M.D., who has the education and training to treat it all: eye diseases, infections and injuries, and perform eye surgery. For more information, visit www.aao.org.

About Ophthalmology
Ophthalmology, the official journal of the American Academy of Ophthalmology, publishes original, peer-reviewed, clinically-applicable research. Topics include the results of clinical trials, new diagnostic and surgical techniques, treatment methods, technology assessments, translational science reviews, and editorials. For more information, visit www.aaojournal.org.

[1] http://www.eyeresearch.org/resources/pdfs/AgeRelatedMacularDegeneration(NEI).pdf

[2] http://www.ncbi.nlm.nih.gov/pubmed/19365036

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SOURCE American Academy of Ophthalmology