A major review by Tien Yi Wong, MD, MPH, PhD, and Singapore Eye Research Institute colleagues concludes that Asians may be just as susceptible to age-related macular degeneration as Caucasians. Asians have long been considered a low risk group for AMD, which is a leading cause of vision loss in older Caucasians. Since the number of elderly people is increasing in Asia, Dr. Wong's study suggests that health systems there need to prepare for an onslaught of AMD.
Pooling results from nine standardized-diagnosis studies in five Asian populations (Japan, China, South Korea, India and Singapore), Dr. Wong's group confirmed prevalence of early-stage AMD as 6.8 percent and late-stage as 0.56 percent, comparable to Caucasians at 8.8 percent and 0.59 percent, respectively. All rates pertain to people aged 40 to 79 years. Also, among those with late AMD, the "wet" (neovascular) form appeared to be more prevalent in Asians than in whites. Asian men were more likely to develop late AMD than white men and much more likely than Asian women.
The researchers speculate that Asian men may be more susceptible to polypoidal choroidal vasculopathy (PCV), abnormal development of blood vessels in the deeper layers of the eye. Whether PCV is a sub-type of AMD or a separate disorder remains controversial; it is also unclear whether PCV responds well to medications that inhibit abnormal blood vessel growth (anti-vascular endothelial growth factor drugs such as Avastin and Lucentis) that help many wet AMD patients keep their vision.
"Future studies should evaluate whether there are 'Asian forms' of AMD and discern other racial/ethnic differences in Asian susceptibility," Dr. Wong said."Our meta-analysis could not adjust for important risk factors like smoking, common among many Asian men; nor did this study include all relevant Asian racial/ethnic groups," he added.
The research appears in the May issue of Ophthalmology, the journal of the American Academy of Ophthalmology.
- Ryo Kawasaki, Miho Yasuda, Su Jeong Song, Shih-Jen Chen, Jost B. Jonas, Jie Jin Wang, Paul Mitchell, Tien Y. Wong. The Prevalence of Age-Related Macular Degeneration in AsiansA Systematic Review and Meta-Analysis. Ophthalmology, 2010; 117 (5): 921 DOI: 10.1016/j.ophtha.2009.10.007
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