Visual Impairment Will Increase as Population Ages, but Treatment Can Mitigate Effects

Health care providers can expect a significant increase in age-related macular degeneration as the baby boom generation reaches retirement age, according to a new study by researchers at RTI International and the Centers for Disease Control and Prevention.

The study, published in the April 2009 issue of Archives of Ophthalmology, predicts that the aging U.S. population over the next 40 years will lead to a large increase in early and advanced age-related macular degeneration. If used universally, existing medical treatments could reduce the expected number of cases of visual impairment and blindness attributable to age-related macular degeneration by as much as 35 percent.

"In the best of circumstances, we should be prepared for a substantial increase in the number of patients with visual impairment and blindness caused by age-related macular degeneration simply because of an aging population." said David Rein, Ph.D., a senior research economist at RTI and the study's lead author. "However, newly discovered prophylactic and treatment therapies for age-related macular degeneration can offset some of the future morbidity from the disease."

The researchers estimated that by 2050 the number of people with early age-related macular degeneration will double in the United States to more than 17.8 million. Without treatment, these patients would be expected to result in approximately 1.6 million cases of visual impairment and blindness in 2050, compared to between 400,000 and 600,000 cases today. In contrast, the projected number of cases would fall 35 percent to 1 million cases if all patients received perfect medical treatment by today's standards.

"Given no change in current medical treatment, the actual number will likely fall somewhere between those two extremes," Rein said.

Treatment options for age-related macular degeneration include vitamin prophylactic therapy for patients with early age-related macular degeneration, and anti-vascular endothelial growth factor (anti-VEGF) injections for certain forms of advanced disease. Vitamin therapy includes beta carotene, Vitamin C, E, zinc and copper, plus lutein, as identified in the landmark AREDS study.

The study found that the universal use of vitamin prophylactic therapy alone by all patients with early age-related macular degeneration could reduce visual impairment and blindness by 23 percent. Vitamin therapy is recommended for use by all patients with early disease, most of whom will never develop visual symptoms of age-related macular degeneration.

In contrast, if used alone, anti-VEGF therapies would be expected to reduce visual impairment and blindness by only 17 percent. In their patented form, anti-VEGFs are far more costly than vitamins, but their use is targeted to the smaller group of patients who have developed advanced disease.

"The good news is that medical technologies are changing rapidly," Rein said. "Only ten years ago, there were no treatments for age-related macular degeneration. With luck, tomorrow's discoveries will lead to far greater reductions in visual impairment and blindness."

In the United States, age-related degeneration is the estimated cause of more than half of visual impairment and 22 percent of blindness among Whites and significantly effects Hispanics and Blacks as well.

The study was funded by the U.S. Centers for Disease Control and Prevention's Division of Diabetes Translation.

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Abstract

Objective To forecast age-related macular degeneration (AMD) and its consequences in the United States through the year 2050 with different treatment scenarios.

Methods We simulated cases of early AMD, choroidal neovascularization (CNV), geographic atrophy (GA), and AMD-attributable visual impairment and blindness with 5 universal treatment scenarios: (1) no treatment; (2) focal laser and photodynamic therapy (PDT) for CNV; (3) vitamin prophylaxis at early-AMD incidence with focal laser/PDT for CNV; (4) no vitamin prophylaxis followed by focal laser treatment for extra and juxtafoveal CNV and anti–vascular endothelial growth factor treatment; and (5) vitamin prophylaxis at early-AMD incidence followed by CNV treatment, as in scenario 4.

Results Cases of early AMD increased from 9.1 million in 2010 to 17.8 million in 2050 across all scenarios. In non–vitamin-receiving scenarios, cases of CNV and GA increased from 1.7 million in 2010 to 3.8 million in 2050 (25% lower in vitamin-receiving scenarios). Cases of visual impairment and blindness increased from 620 000 in 2010 to 1.6 million in 2050 when given no treatment and were 2.4%, 22.0%, 16.9%, and 34.5% lower in scenarios 2, 3, 4, and 5, respectively.

Conclusion Prevalence of AMD will increase substantially by 2050, but the use of new therapies can mitigate its effects.

Source

David B. Rein; John S. Wittenborn; Xinzhi Zhang; Amanda A. Honeycutt; Sarah B. Lesesne; Jinan Saaddine; for the Vision Health Cost-Effectiveness Study Group. Forecasting Age-Related Macular Degeneration Through the Year 2050: The Potential Impact of New Treatments. Arch Ophthalmol. 2009;127(4):533-540.

RTI International Released: Mon 13-Apr-2009

Key concepts: Multivitamin, AREDS, age-related eye disease study, macular degeneration