Ann Arbor, MIScientists at the University of Michigan have shown that their new metabolic imaging instrument can accurately detect eye disease at a very early stage. Such a device would be vision-saving because many severe eye diseases do not exhibit early warning signals before they begin to diminish vision. The testing is noninvasive and takes less than 6 minutes to administer to a patient.
In a recent study, two researchers from the U-M Kellogg Eye Center used the instrument to measure the degree to which a subtle visual condition affected six women. Victor M. Elner, M.D., Ph.D., and Howard R. Petty, Ph.D., report their findings in the February issue of Archives of Ophthalmology. 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 womans 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: visual fields, visual acuity, and pupillary light response. In each case the imaging instrument provided results that were equal to and often superior to the standard tests.
The study grew out of Petty and Elners observation that metabolic stress at the onset of disease causes certain proteins to become fluorescent. To measure the intensity of this flavoprotein autofluorescence (FA), they designed a unique imaging system equipped with state-of-the art cameras, filters, and electronic switching, together with customized imaging software and a computer interface.
Petty, a biophysicist and expert in imaging, explains why FA data is a good predictor of disease. Autofluorescence occurs when retinal cells begin to die, often the first event in diseases like glaucoma and diabetic retinopathy, he says. Cell death can be observed microscopically, but not as yet t
|Contact: Betsy Nisbet|
University of Michigan Health System