Latinos living in the United States have high rates of eye disease and visual impairment, according to a research study, and a significant number may be unaware of their eye disease.
This study, called the Los Angeles Latino Eye Study (LALES), is the largest, most comprehensive epidemiological analysis of visual impairment in Latinos conducted in the U.S. It was funded by the National Eye Institute (NEI) and the National Center on Minority Health and Health Disparities (NCMHD), two components of the Federal government's National Institutes of Health (NIH). Study results are published in the June, July and August 2004 issues of the journal Ophthalmology.
Researchers found that Latinos had high rates of diabetic retinopathy, an eye complication of diabetes; and open-angle glaucoma, a disease that damages the optic nerve.
Study investigators gave a detailed health interview and clinical examination to more than 6,300 Latinos, primarily Mexican-Americans, aged 40 and older from the Los Angeles area, assessing their risk factors for eye disease and measuring health-related and vision-related quality of life. Each participant received a blood test for diabetes and a comprehensive eye exam that included photographs of the back of the eye.
"This research has provided much needed data on eye disease among the fastest growing minority group in the United States," said Elias A. Zerhouni, M.D., director of the NIH.
"Several epidemiological studies have been conducted on the prevalence and severity of major eye diseases in White and Black populations, however there have been relatively few such studies in Latino populations," said Paul A. Sieving, M.D., Ph.D., director of the NEI. "This study highlights the importance of providing health education and vision care to Latinos."
The researchers noted that many study participants did not know they had an eye disease. One in five individuals with diabetes was newly diagnosed during the LALES clinic exam, and 25 percent of these individuals were found to have diabetic retinopathy. Overall, almost half of all Latinos with diabetes had diabetic retinopathy. Among those with any signs of age-related macular degeneration (AMD), a condition that can lead to a loss of central vision, only 57 percent reported ever visiting an eye care practitioner, and only 21 percent did so annually. Seventy-five percent of Latinos with glaucoma and ocular hypertension (high pressure in the eye) were undiagnosed before participating in LALES.
"Because vision loss can often be reduced with regular comprehensive eye exams and timely treatment, there is an increasing need to implement culturally appropriate programs to detect and manage eye diseases in this population," said Rohit Varma, M.D., M.P.H., associate professor of ophthalmology and preventive medicine at the Keck School of Medicine's Doheny Eye Institute at the University of Southern California, and director of the study. "This is especially true when you consider that Latinos, compared with other ethnic groups in the U.S., have a high prevalence of low vision, diabetic retinopathy and glaucoma. Overall, Latinos were much more likely to have received general medical care than to have received eye care."
The study found that:
- Three percent of LALES participants were visually impaired, defined as best corrected visual acuity of 20/40 or worse in the better seeing eye, and 0.4 percent were blind, defined as best corrected visual acuity of 20/200 or worse in the better seeing eye. Prevalence rates of visual impairment in Latinos are higher than those reported in Whites and comparable to those reported in Blacks. Visual impairment increased with age. Those in their 70s and 80s were up to eight times more likely to have visual impairment than their younger counterparts. Other risk factors for visual impairment included female gender, low education, unemployment, a history of eye disease, and diabetes.
- Nearly half of all study participants with diabetes-almost a quarter of the LALES population-had some signs of diabetic retinopathy. Longer duration of diabetes was associated with a higher risk of retinopathy. In addition, more than 10 percent of participants with diabetes had macular edema (fluid buildup in the back of the eye), of whom 60 percent had cases severe enough to require laser treatment. Latinos had a higher rate of more severe vision-threatening diabetic retinopathy than Whites.
- The overall prevalence of open-angle glaucoma among Latinos in this study was nearly five percent. This rate increased with age from about eight percent for those in their 60s to 15 percent for those in their 70s. This is higher than the rate reported for Whites and similar to that for Blacks in this country. Nearly four percent of Latinos had ocular hypertension, a risk factor for glaucoma.
- About 10 percent of participants were considered to be at risk for progression to more advanced stages of AMD, and close to a quarter of these individuals had signs of AMD in both eyes. Only 25 individuals had advanced AMD, a prevalence rate of 0.5 percent. Age was a strong predictor for development of more advanced stages of AMD. While Latinos had the early signs of AMD at rates comparable to Whites, the rates of advanced AMD were lower than seen in Whites and comparable to Blacks.
- One in five adult Latinos had cataract. Half of Latinos with cataract or other clouding of the lens were visually impaired.
- Latinos with visual impairment based on the study eye examination reported lower visual function on a questionnaire. In particular, those whose vision had worsened by two lines or more on a standard eye chart were more likely to report a lower quality of life.
"Census 2000 data show that 12.5 percent of residents in this country, or 35 million people, are Latino," said John Ruffin, Ph.D., director of the NCMHD. "That number is projected to increase to 61.4 million by the year 2025. This study re-affirms the significance of eye disease and visual impairment among Latinos, and its importance to public health," Ruffin said.