'Fluorescent' Retinal Cells Warn of Eye Disease
MONDAY Feb. 11, 2008 -- That twinkle in your eye could be an early sign of eye disease if it is seen using a new imaging device developed by scientists at the University of Michigan.
The device detects certain proteins that become fluorescent during the metabolic stress that typically happens at the onset of eye diseases, according to findings published in the February issue of the Archives of Ophthalmology. This flavoprotein autofluorescence (FA) occurs when retinal cells begin to die.
"Autofluorescence occurs when retinal cells begin to die, often the first event in diseases like glaucoma and diabetic retinopathy," study co-author Howard Petty, a biophysicist and expert in imaging with the university's Kellogg Eye Center, said in a prepared statement. "Cell death can be observed microscopically, but not as yet through any current imaging methods. We believe this study is a big step forward, toward creating a diagnostic tool that can characterize disease long before symptoms or visible signs appear."
Many severe eye diseases do not show early symptoms before they begin to diminish vision. Using this device to test a patient is noninvasive and takes less than six minutes, according to the study.
In the study, Petty and fellow researcher Victor M. Elner used the instrument to measure the degree to which a subtle visual condition affected six women. The women had been recently diagnosed with pseudotumor cerebri (PTC), a condition that mimics a brain tumor and often causes increased pressure on the optic nerve that can lead to vision loss.
Because each woman's disease was in a very early stage, the researchers could evaluate how accurately the instrument would detect vision loss as compared to several standard tests used to evaluate vision. In each case, their imaging instrument provided results that were equal to and often superior to the standard tests.
The researchers also found that FA data more accurately described the degree of disease in each patient's eye as compared to the standard vision tests. The patients with PTC had FA values that averaged 60 percent greater in the eye that was more severely affected, the study said. By contrast, an age-matched control group had no significant difference in FA values between their healthy eyes.
"Early treatment for eye disease is so important, and this study suggests that FA activity is a very good indicator of eye disease," Elner, an ophthalmologist and a pathologist, said in a prepared statement. "Cardiologists have long used blood pressure testing to head off heart disease. We believe that FA testing will likewise be a helpful diagnostic tool for eye doctors looking to prevent blindness."
Elner and Petty have patented the device and are investigating its use as a screening device in diabetes and major eye diseases.
The National Eye Institute has more about eye diseases and disorders.
Posted: February 2008
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