Conducted primarily among Los Angeles-area residents of Mexican descent, the five-year study represents the most comprehensive effort to track the causes of blindness and access to eye care among the nation's fastest-growing ethnic group. Study leader Rohit Varma, M.D., M.P.H., associate professor of ophthalmology at the Keck School of Medicine of USC and the Doheny Eye Institute, presented the findings today at the annual meeting of the Association for Research in Vision and Ophthalmology (ARVO).
"Latinos are expected to make up about 26 percent of the U.S. population by 2025," Varma says. "It's important to get an estimate of disease in Latinos, and we found a lot of vision-related problems in this community that need to be addressed."
When taken as a whole, the rate of vision problems among Latinos seems low. Since the U.S. Latino population tends to be younger than most other ethnic groups, though, the statistics are deceiving. Varma explains that vision impairment usually starts to rise after age 40, and rates of eye problems among older Latinos are higher than those among older members of other racial or ethnic groups. Varma expects to see more vision problems as the Latino population ages.
The study team enrolled more than 6,200 Latino men and women over the age of 40 who lived in the communities in and around the city of La Puente, Calif. Researchers screened participants for eye disease, high blood pressure and diabetes. They also interviewed participants about eye disease risk factors such as weight, health care access, family history of eye disease and alcohol use.
Vision impairment is defined as having 20/40 vision or worse in the better eye, even with eyeglasses, Varma explains. Latinos have the following rates of vision impairment, by age range:
For details on ethnic rates, go to www.nei.nih.gov/eyedata/pdf/VPUS.pdf.
Initial data on 5,714 participants age 40 and older who were examined show 107 (2 percent) were visually impaired in one eye and 280 (5 percent) were impaired in both eyes. As in other ethnic groups, cataracts are the most common cause of vision impairment among Latinos, accounting for 47 percent of visual impairment in both eyes and 41 percent of one-sided vision impairment.
After cataract, the leading causes of bilateral vision loss are diabetic retinopathy (10 percent) in the 40-64 age group and age-related macular degeneration in those age 65 and above. Besides cataract, leading causes of vision impairment in one eye were amblyopia (13 percent) in the 40-64 age group and age-related macular degeneration (4 percent) in those age 65 and above.
Although more Latinos have impaired vision, "blindness rates were not as high in Latinos as others," Varma says. Major causes of blindness are age-related macular degeneration and diabetic retinopathy.
Varma hopes health educators will use the data to find effective outreach strategies and that health care workers in local communities will use them to plan care services. They will also be useful to national health policymakers trying to understand the breadth of public health problems, as well as to scientists seeking the reasons behind differences in disease prevalence between ethnicities.
Keck School faculty members Stanley P. Azen, Susan Preston-Martin and Ronald Smith were investigators in the study. The National Eye Institute supported the research.
For copies of abstracts online, go to www.arvo.org and click on the annual meeting link. Prevalence and causes presentations are part of poster session 237, 5:15 p.m.-7:15 p.m. EDT May 5.