Originally Released: July 26, 2000
Contact: Ellen Beth Levitt, firstname.lastname@example.org, 410-328-8919
When most people hear the term "lazy eye," they think of an eye that drifts to one side. But to ophthalmologists, lazy eye is another term for amblyopia, a condition in which vision is decreased in one eye. Amblyopia affects up to 4 percent of children and adults in the U.S. The vision loss, which begins in childhood, is a life long problem and cannot be corrected with lenses. However, research is providing new clues that may lead to better treatment. Researchers at the University of Maryland School of Medicine in Baltimore have detected previously unknown abnormalities in the retina of people with moderate and severe amblyopia. Their preliminary findings were presented at the Association for Research in Vision and Ophthalmology (ARVO) conference in May.
"The conventional thinking has been that amblyopia results in structural and functional changes in the brain," says researcher Kelly Hutcheson, M.D., assistant professor of ophthalmology at the University of Maryland School of Medicine and director of pediatric ophthalmology at the University of Maryland Hospital for Children. "Now we are seeing abnormalities in the retina, which tell us that there may be another element to the problem as well," explains Dr. Hutcheson. The researchers do not know why these changes occur.
To detect the abnormalities in amblyopic patients, the researchers used new Multifocal Electroretinogram (M-ERG) technology. The M-ERG uses a high intensity beam of light to measure the retina's reaction to light. During the exam, a patient wears a special contact lens, which detects electrical impulses from the retina as the light shines upon it. The data are then used to create a map of the eye. The M-ERG data from the amblyopic eye were compared with data from the patient's healthy eye and with patients who do not have the disorder. According to the study, patients with visual acuity of 20/50 or worse showed a reduced response to light on the M-ERG test, which indicates an abnormality. However, no M-ERG changes were detected among amblyopic patients with a visual acuity better than 20/50 or among patients without lazy eye.
"The new multifocal ERG is much more sophisticated than previous tests," says researcher Mary A. Johnson, M.D., associate professor of ophthalmology at the University of Maryland School of Medicine. "With this test, we can measure 108 different points along the retina. This allows us to detect subtle abnormalities which couldn't be detected before," explains Dr. Johnson.
"I think these findings can give us a greater understanding of what is happening with the eye of the amblyopic patient. Some day this may lead to a better treatment, but clearly more research is needed," adds Dr. Hutcheson.
In addition to this study, the University of Maryland School of Medicine is taking part in a nationwide clinical trial to determine the most effective treatment for children with amblyopia. One method uses drops of the drug Atropine. The medication blurs the vision in the child's "good" eye, which forces the weaker, amblyopic eye to work harder and see better. Another treatment works in the same way, but replaces the drops with a patch, which covers the "good" eye.
Researchers are looking for children between age three and seven with moderate reductions in vision to take part in the study. Anyone interested in enrolling or finding out more information can call the University of Maryland Hospital for Children at (410) 328-5746. The study is sponsored by the National Eye Institute.
For patient inquiries, call 1-800-492-5538 or click here to make an appointment.