AMD eye disease will increase, but new therapies can reduce blindness, study reports

APRIL 14, 2009--Laser and photodynamic therapies are part of an arsenal against age-related macular degeneration (AMD) that will become increasingly important in coming years say the authors of a new study. AMD, an eye disease that can cause vision loss, and is projected to increase substantially. The researchers note that efforts should be undertaken to improve access to all therapies, including laser treatments, which can assist at later stages of the disease.

APRIL 14, 2009--"Public prevention efforts should focus on expanding the use of antioxidant vitamins in people with early AMD," wrote the authors of a new report on age-related macular degeneration (AMD), an eye disease that is projected to increase substantially. The researchers added that efforts should also be undertaken to improve access to laser and photodynamic treatments, and other therapies.

AMD occurs when the macula, the area of the eye's retina responsible for sharp vision, begins to deteriorate. In 2000, as many as 1.75 million Americans reached the vision-threatening stages of the disease. "The prevalence of AMD and its resultant morbidity [illness and disability] is likely to increase as the U.S. population ages," the authors write. Thankfully, though, the use of new therapies is expected to help mitigate its effects on vision, according to results of simulation modeling the researchers reported in the April issue of Archives of Ophthalmology.

Preventive therapies include antioxidant vitamins that could slow the progression of AMD from early to late stages. Treatments for more advanced forms of AMD include laser and photodynamic therapies and anti–vascular endothelial growth factor (anti-VEGF) injections.

To estimate the possible effects these new treatments might have on future disease burden, David B. Rein, Ph.D., of RTI International (Research Triangle Park, NC), and colleagues simulated cases of AMD and related complications for the years 2010 through 2050. Using existing data to estimate the number of individuals in each stage of the disease based on age, sex and race or ethnicity, they modeled the population's progression over time under five different treatment scenarios. These ranged from no treatment at all to combinations of vitamins to prevent progression of early AMD with laser and anti-VEGF therapies for those at later stages.

"Cases of early AMD increased from 9.1 million in 2010 to 17.8 million in 2050 across all scenarios," the authors write. However, the forecast indicated that the rate of visual impairment and blindness due to AMD could be reduced from 0.73 percent with no treatment to 0.48 percent when combining the use of antioxidant vitamins for prevention and anti-VEGF and laser therapy for individuals with AMD.

"Our model predicts large increases in both cases of early and advanced AMD and the visual impairment and blindness attributable to it over the next 40 years regardless of the treatment steps taken, with virtually all of these increases attributable to the aging of the U.S. population," the authors continue. "However, existing medical therapies have the potential to reduce the visual impairment and blindness attributable to AMD by as much as 35 percent, translating to 565,000 fewer cases of visual impairment and blindness in 2050."

With an annual cost of approximately $100 per patient, vitamin therapy is a cost-effective method of delaying AMD progression, but research indicates it is not widely used among patients with early-stage disease.

For more information see the paper Forecasting Age-Related Macular Degeneration Through the Year 2050: The Potential Impact of New Treatments, at the Archives of Ophthalmology.

Posted by Barbara G. Goode, barbarag@pennwell.com, for BioOptics World.

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