Keck Medicine Summer 2011

Eye-Opening Research

Thanks to participation in a research study, Margarita Tovar continues to see and enjoy the activities of her daily life.

Landmark study reveals that Latinos have higher rates of eye disease. Keck team now sets its sights on uncovering possible genetic risk factors

By Carrie St. Michel

Photos by Phillip Channing

“If I hadn’t opened the door,” explains Margarita Tovar, “I wouldn’t have been part of the study, and I could have lost my vision.”  

Tovar is referring to the Los Angeles Latino Eye Study (LALES) – the largest, most comprehensive study ever of eye disease and eye health among adult Latinos living in the United States. Set in the Southern California city of La Puente, this landmark research initiative has spanned more than a decade, producing a prodigious database that paints the clearest picture to date of ocular challenges unique to the Latino community.

This unparalleled study, which currently is in its third phase, has resulted in sweeping impacts on the national, as well as the individual, level. At the national level, LALES results prompted Medicare to modify benefits to include coverage of glaucoma screenings
for Latinos. In addition, the American Academy of Ophthalmology launched a vision-screening program designed specifically to combat undetected eye disease and visual impairment among Latinos.   

At an individual level, Margarita Tovar is representative of thousands who have benefitted from LALES. Having been with the study from its start, the 62-year-old Tovar has completed three extensive eye examinations. The most recent screening, she says, saved her eyesight. “I didn’t know how bad my glaucoma was,” Tovar notes. “I was laid off and don’t have insurance, so LALES referred me to an ophthalmologist at the [Los Angeles County+USC Medical Center] eye clinic. Otherwise, I wouldn’t have the glaucoma eye drops I need. The ophthalmologist is also monitoring the [age-related] macular degeneration that LALES diagnosed.”

DETERMINED TO FIND ANSWERS  Tovar and many others owe their preserved eyesight to the curiosity of Rohit Varma, M.D., M.P.H., professor of ophthalmology and preventive medicine at the Keck School of Medicine of USC and director of the Ocular Epidemiology Center at the Doheny Eye Institute at USC. The institute is ranked eighth in the nation in ophthalmology, according to the U.S. News & World Report best hospitals rankings.

Rohit Varma, M.D., M.P.H., directs the largest, most comprehensive study ever of eye disease among adult Latinos living in the United States.

In the early 1990s, Varma was completing a glaucoma fellowship at Doheny. The majority of patients were Latino, and he quickly discovered no database existed to validate or refute his suspicion that this group had a high incidence of visual impairment and eye disease. As he recalls, “I remember thinking, ‘This is the fastest- growing ethnic group in the U.S., and yet we have no idea what impact eye disease is having on their lives or what type of eye services should be in place.’”

Determined to find answers, Varma applied for – and was awarded – a grant from the National Eye Institute (NEI), which is part of the National Institutes of Health (NIH). LALES was thus born, with Varma and Stanley Azen, Ph.D., Keck professor and co-director of biostatistics, Department of Preventive Medicine, as co-principal investigators. As a result of LALES and other groundbreaking ocular research, the Doheny Eye Institute currently receives the second-highest amount of NIH funding among ophthalmology programs nationwide.      

LALES I  With NEI funding in place, the knocking on doors – literally – began. Surveyors fanned out across the city of La Puente to find Latino adults, aged 40 and above, who were willing to participate in the study. La Puente was selected for its large Latino population (primarily of Mexican origin) and its proximity to LAC+USC (in the event urgent medical care was needed).

A LALES clinic was opened in La Puente, and a team of Keck ophthalmologists and technicians launched the study’s first phase. From 1999 to 2003, free, comprehensive eye exams were given to 6,357 La Puente residents. These baseline assessments were designed to assess the prevalence of vision loss and the major, blinding eye diseases – cataract, glaucoma, diabetic retinopathy and age-related macular degeneration (AMD). The baseline study also assessed eye disease from the perspectives of risk factors, impact on quality of life, eye-care utilization and bar-
riers to care.                        

The overarching LALES I finding was that – compared to any other ethnic group nation- wide – Latinos have higher rates of developing visual impairment, blindness, diabetic retinopathy and cataracts.

For Varma, however, the headline was this: “The most important finding was that 60 percent of their eye disease had gone undiagnosed. And that percentage rose significantly within specific disease categories.”  In fact, 98 percent of AMD went undetected, as did 95 percent of diabetic retinopathy, 82 percent of glaucoma, 57 percent of cataracts and 19 percent of refractive error. Pointing to at least a partial
explanation, Varma notes that only 57 percent of LALES participants had vision insurance.

Another noteworthy finding was that one in five participants with diabetes was newly diagnosed during the LALES exam, and 23 percent of these individuals were found to have diabetic retinopathy.

LALES II  LALES II, which was again funded through an NEI grant, took place from 2004 through 2009 and involved reassessing nearly 80 percent of the study’s original participants. Findings included:

•  Over the four years, 34 percent of diabetic participants developed diabetic retinopathy; of those who’d been diabetic for more than 15 years, 42 percent developed diabetic retinopathy.
•  Of those with diabetic retinopathy at the beginning of the study, 39 percent showed worsening of the disease four years later.
•  Participants who already had visual impairment, blindness or diabetic retinopathy in one eye at the study’s start, had very high rates of developing the condition in the other eye during the study.

“These results underscore the importance of Latinos, especially those with diabetes, getting regular, dilated eye exams to monitor their health,” observes Varma. “Eye care professionals should closely monitor Latinos who have eye disease in one eye, because their quality of life can be dramatically impacted if they develop the condition in both eyes.”

Roberta McKean-Cowdin, Ph.D., assistant professor of research in the Keck School’s Department of Preventive Medicine, concurs. In her role as LALES’ epidemiologist, McKean-Cowdin found, “A two-line loss [on an eye chart] is associated with a five-point loss in quality of life, and that significantly impacts areas such as independence and daily tasks like driving.”  Based on these findings, she adds, “Screenings and treatment need to begin very early, because even small losses of vision have a big impact.”

This art was created to represent the Los Angeles Latino Eye Study
by Latino illustrator  José Ramirez.

“ Screenings and treatment need to begin very early, because even small losses of vision have a big impact.”
— Roberta McKean-Cowdin, Ph.D., assistant professor of research in the Keck School’s Department of Preventive Medicine

NEI-funded LALES III, which was launched last year and will continue through 2015, involves the third retesting of the study’s original participants to assess the progression of existing eye disease and to diagnose any new conditions. An added wrinkle this time around is determining if Latinos have a genetic predisposition to develop certain eye diseases.

Toward that end, co-principal investigator Azen and his team – including Keck professor of preventive medicine James Gauderman, Ph.D., and Keck assistant professor of preventive medicine Paul Marjoram, Ph.D. – have the arduous task of merging complex genetic databases. While challenges come with the territory, so too does tremendous potential.

“The beauty of big databases,” Azen says, “is that they open up opportunities for data mining, and that
can lead to public health improvements that go beyond even the original aims of the study.”

In addition to shepherding LALES III, Varma is heading a study in which some 9,000 Los Angeles-area preschool children – African American, Asian, Caucasian and Latino – were assessed for eye disease. Commenting on the soon-to-be-released results, Varma says, “This is very important data that will help inform how children’s vision screenings should  be conducted.”

LALES’ LEGACY  While the ultimate impact of LALES is still unfolding, La Puente Mayor David Argudo succinctly sums up the study’s impact thus far:

“Their efforts have saved the eyesight of so many citizens in our community. Our heartfelt thanks go out to LALES.”   •
University of Southern California University of Southern California