'Fluorescent' cells give early warning for eye diseaseFebruary 25, 2008A device that measures metabolic stress could help eye doctors diagnose disease before symptoms appear Ann Arbor, MI-Scientists 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 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: 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 Elner's 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 though 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." The women in the study were newly diagnosed with PTC and had not yet received treatment. According to standard tests they had good visual acuity, and their visual field tests indicated either subtle abnormalities or none at all. Visual field testing, used to measure the area seen by the eye, is a standard tool for evaluating eye diseases such as glaucoma. After the standard vision tests were administered, the researchers measured FA values for the six women and the age-matched control group. All of the patients with PTC had higher FA values in the eye that was more severely affected. In fact, FA values averaged 60% greater in the more affected eye of these women. By contrast, the control group had no significant difference in FA values between their healthy eyes. The researchers also found that FA data more accurately described the different degree of disease in each eye for a given patient, as compared to the standard vision tests. Elner, who is an ophthalmologist and a pathologist, says that the ability to detect subtle distinctions is important. "Early treatment for eye disease is so important, and this study suggests that FA activity is a very good indicator of eye disease," he says. "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 through the U-M Office of Technology Transfer. They are investigating its use as a screening device in diabetes and other major eye diseases. University of Michigan Health System |
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| Related Eye Disease Current Events and Eye Disease News Articles Cataract surgery helps AMD patients; steroid improves DME; online eye health forum This month's Ophthalmology, the journal of the American Academy of Ophthalmology (Academy) reports on a national study that finds cataract surgery is likely to benefit patients with age-related macular degeneration (AMD) at all stages of the disease, on a clinical trial showing that the steroid triamcinolone may be effective in advanced diabetic macular edema (DME) patients when standard treatment fails, and on the public's use of two Academy-sponsored online eye health forums. Experimental treatments restore partial vision to blind people Two experimental treatments, a retinal prosthesis and fetal tissue transplant, restored some vision to people with blinding eye diseases. The findings, presented at Neuroscience 2009, the annual meeting of the Society for Neuroscience and the world's largest source of emerging news on brain science and health, may lead to new treatments for the blind. Cancer drug is no different in effectiveness as gold standard treatment for macular degeneration Investigators from Boston University School of Medicine (BUSM) and the VA Boston Healthcare System have shown, at 6 months in a small group of patients, that there is no difference in efficacy between Bevacizumab (Avastin) and Ranibizumab (Lucentis) for the treatment of age-related macular degeneration (AMD). Toronto researchers discover novel circulation in human eye, new glaucoma treatment target Researchers at the University of Toronto, St. Michael's Hospital and Sunnybrook Health Sciences Centre have discovered a previously unidentified form of circulation within the human eye which may provide important new insights into glaucoma, a leading cause of blindness. International conference on endothelin One of the most intriguing developments in recent medical science is the discovery of the human chemical endothelin (ET). JDRF-funded studies show regular CGM use increases diabetes control for all age groups The latest data from groundbreaking human clinical trials of the effectiveness of continuous glucose monitors (CGM) show that the primary determinant of improvements in achieving better diabetes control is regular use of monitors - six days per week or more - rather than the age of patients, and that benefits continue well past the time when people with type 1 diabetes begin using the devices - including experiencing fewer low blood sugar emergencies. Elevated arginase levels contribute to vascular eye disease such as diabetic retinopathy Elevated levels of the enzyme arginase contribute to vascular eye damage and Medical College of Georgia researchers say therapies to normalize its levels could halt progression of potentially blinding diseases such as diabetic retinopathy. Anti-growth factor drugs raise hope and concern for treatment of children's eye diseases A new class of antibody drugs may provide a powerful new tool for the treatment of eye diseases in children, but specialists need to be alert for the possibility of serious side effects, according to an editorial in the August Journal of AAPOS (American Association for Pediatric Ophthalmology and Strabismus), published by Elsevier. Natural Compound Stops Diabetic Retinopathy Researchers at the University of Oklahoma Health Sciences Center have found a way to use a natural compound to stop one of the leading causes of blindness in the United States. U finds treatment that significantly slows progression of eye damage in persons with type 1 diabetes University of Minnesota Medical School researcher Michael Mauer, M.D., has found a treatment that significantly slows the progression of eye injury in people with type 1 diabetes, a common complication caused by this disease. More Eye Disease Current Events and Eye Disease News Articles |
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