EyeNet Magazine >> Comprehensive
Comprehensive
What to Look for in Hispanic Patients
by Richard Trubo, Contributing Writer
For many years, ophthalmologic researchers seemed to turn a blind eye on visual problems among Hispanic-Americans. That’s no longer true. While much less is known about eye disorders and visual loss in Hispanics than in Caucasians or African-Americans, those circumstances are changing rapidly.
And the timing is right. As America’s demographics change, people of Hispanic origin have become the fastest-growing ethnic minority in the United States, now making up about 12 percent of the country’s population. According to Sheila K. West, PhD, professor of ophthalmology at Johns Hopkins University’s Wilmer Eye Institute, the number of Hispanics aged 55 and older—the age group at greatest risk for age- related eye diseases—is expected to double by the year 2025.
Not Just Diabetes
One of the largest studies of Hispanics was a joint effort of investigators at the University of Arizona, Johns Hopkins and other institutions. Called Proyecto VER (Project Vision Evaluation and Research), this population-based survey collected data on blindness and visual impairment in more than 4,700 U.S. Hispanics aged 40 and older living in Tucson and Nogales, Ariz. “When we started Proyecto VER, there were absolutely no data on blindness and visual impairment in the Hispanic community,” recalled Dr. West.
In one recent paper, Proyecto VER researchers reported that the most common cause of bilateral blindness in Hispanics was open-angle glaucoma—a finding at variance with other population-based blindness surveys in which age-related macular degeneration was the primary cause in whites. The same study found that the leading cause of visual impairment in Hispanic adults was cataracts (responsible for 42 percent of cases of visual deficits), followed by AMD (15 percent) and diabetic retinopathy (13 percent).1
In California, Rohit Varma, MD, MPH, leads the Los Angeles Latino Eye Study, an ongoing five-year-old examination of the prevalence and causes of vision problems among more than 6,300 L.A.-area residents of Mexican descent.
At this year’s Association for Research in Vision and Ophthalmology annual meeting, Dr. Varma, associate professor of ophthalmology at the University of Southern California, reported that Latinos have higher rates of glaucoma and early AMD, compared with whites, although the incidence of late AMD was similar in whites and Latinos. Among those Latinos found to have glaucoma in the L.A. study, about three-fourths had never been diagnosed.
Dr. Varma’s data also have shown that overall, older Latinos are more likely to have visual impairment than older men and women in other racial and ethnic groups. “It could be related to genetics, diet, access to care, greater exposure to UV light—it could be a number of factors,” he explained.
Diabetes Challenge
A key contributor to eye diseases in Hispanic-Americans is their high rate of diabetes, which has translated into an elevated incidence of diabetic retinopathy. According to the Vision Problems in the U.S. report (2002) from the NEI and Prevent Blindness America, while white Americans have an elevated rate of diabetic retinopathy before age 40, Hispanics have a higher incidence at later ages.
In 2001, the Proyecto VER researchers reported that 22 percent of their age-40-and-over study population had diabetes, nearly twice the rate found among Caucasians. In Los Angeles, Dr. Varma’s study has shown the same high rates of diabetic retinopathy among Latinos, as well as an increased prevalence of early AMD and glaucoma.
The L.A. Latino Eye Study has also found that about two-thirds of the Latino men and women who reported having diabetes were not adhering to American Diabetes Association guidelines for vision care, including an annual dilated eye exam. Similar findings emerged from a 2002 survey by the Utah Department of Health, which showed that nearly one in five Hispanic diabetics had never received an eye exam.
Not All the Same
About 60 percent of the Hispanics in the United States are of Mexican origin or ancestry, but they aren’t the only bloc of Latinos growing in number or experiencing eye disorders at higher rates. Some studies have teased out the incidence of visual impairment in Hispanic subgroups—that is, Mexican-Americans vs. Cuban-Americans vs. Puerto Ricans.
“If you look at the papers we’ve published, Puerto Ricans have demonstrated more functional visual impairment than other Hispanic groups,” said Byron L. Lam, MD, associate professor of ophthalmology at the University of Miami. “The group that has the highest educational level and is the most well off economically—namely, Cuban-Americans—have fairly low visual impairment compared with other Hispanic groups, which may be a function of their greater resources that allow better access to care.”
In one study, Dr. Lam and his colleagues analyzed the prevalence of visual impairment in children and adolescents aged 6 to 19. They found that Puerto Ricans had a significantly higher incidence of usual-corrected visual acuity impairment than other ethnic groups (non-Hispanic whites, Cuban-Americans, Mexican-Americans); the prevalence of 20/30 or worse distance visual acuity with usual or habitual correction was 19.1 percent in Puerto Ricans, compared with 10.8 percent in non-Hispanic whites.2
Obstacles to Care
While Hispanic-Americans may have higher rates of visual problems overall than other ethnic groups, they may not be receiving comparable eye care. Dr. West said that a myriad of socioeconomic and other factors may contribute to visual impairment in Hispanics.
In the Proyecto VER study population, the leading risk factors for not having cataract surgery in persons with a severe cataract included a lack of health insurance, having less than a high school education, and speaking “only or mostly Spanish.” The researchers noted that previously undetected type 2 diabetes was more likely to be found in Mexican-Americans with no regular source of health care and no insurance, compared with individuals whose diabetes had already been diagnosed. Low-income Mexican-Americans (less than $20,000 per family per year) had a higher risk of developing proliferative retinopathy.3
Economics also figured into the ability to correct refractive error. “People would tell us that one of the primary reasons for not getting glasses was simply not having the resources to obtain a glasses prescription,” said Dr. West.
Exam Caveats
The eye examination itself, of course, should not vary with the ethnic background of the patient. Nevertheless, there are a few caveats to keep in mind:
Communication needs. Some Latinos, said Dr. Varma, have a suspicion of the health care system, which translates into a reluctance to seek medical care. But when they do receive care, the doctor-patient relationship can be enhanced when a Spanish-speaking clinician is involved.
He stressed the value of relying on Spanish as the language of communication between doctor and patient, spoken by clinicians who are native Spanish speakers. “I cannot tell you how important this is,” Dr. Varma said. “A native Spanish speaker can create an entirely different level of trust and confidence. Everyone in our study who has had contact with patients is a native Spanish speaker, including ophthalmologists, technicians, secretaries, interviewers and supervisors.”
IOP cutoff. When investigators looked at the higher prevalence of glaucoma in Mexican-Americans, they concluded that screening using a cutoff of 22 mmHg (in the eye with a higher pressure) would miss 80 percent of the open-angle glaucoma cases.4 Dr. West, a coauthor of that study, said that the idea that IOP should be used as a definition of glaucoma just doesn’t hold water, particularly in this population. “Visual field loss is probably the best measure we have right now to determine whether there is glaucomatous damage.”
Corneal thickness. As part of the L.A. Latino Eye Study, researchers have noted that the central corneal thickness in Latinos is less than what has been reported in whites (but greater than that observed in African-Americans and Asians). As a result, the routine measurements of IOP in Latinos may be underestimated in eyes with thinner central corneas.5 “So when one measures IOP in Latinos and it’s low, it doesn’t necessarily mean that it’s truly low—it could be low just because the cornea is thinner in those eyes,” said Dr. Varma.
As a result, he added, “We should make an even greater effort at confirming whether or not these patients have glaucoma.”
Next Steps
A number of other studies of Hispanic-Americans are under way or in the planning stages. At Bascom Palmer, for example, investigators will soon begin evaluating eye health in cohorts of Cuban-Americans and Puerto Ricans.
Meanwhile, Dr. Varma cites the pressing need for outreach and education programs to provide Latinos with information about and screening for eye disorders. “We’re going to have to devise specific programs that are culturally appropriate, directly targeting this population.”
_____________________________
1 Rodriguez, J. et al. Ophthalmology 2002; 109:737–743.
2 Lee, D. J. et al. Paediatr Perinat Epidemiol 2000;14:357–362.
3 West, S. K. et al. Am J Ophthalmol 2002; 134:390–398.
4 Quigley, H. A. et al. Arch Ophthalmol 2001;119:1819–1826.
5 Hahn, S. et al. Invest Ophthalmol Vis Sci 2003;44(4):1508–1512.
