Test May Detect Diabetes-Related Vision Problems Early
< July 16, 2008 > -- A just-released study shows that a new vision screening device, already shown to give an early warning of eye disease, could give physicians and patients a head start on treating diabetes and its vision complications.
The instrument is able to capture images of the eye that reveal metabolic stress and tissue damage, even before the first signs and symptoms of disease appear, says a team at the University of Michigan. The technology measures a phenomenon called flavoprotein autofluorescence (FA), which is thought to be a reliable indicator of eye trouble.
The report is published in the July issue of the Archives of Ophthalmology. It shows the potential of the new tool to screen for diabetes and determine its severity.
If further testing confirms the results to date, the new instrument may be useful for screening people who are at risk of diabetes but have not been diagnosed.
There are some 24 million Americans with diabetes and 57 million more who have pre-diabetes, according to the US Centers for Disease Control and Prevention (CDC). In addition, 4.1 million people over 40 suffer from diabetic retinopathy.
Diabetic retinopathy, which can eventually lead to blindness, is a common complication of diabetes.
Checking the Retina for Disease
"The concept behind measuring FA in the retina is to determine whether there's a metabolic dysfunction in the retinal tissue," explains lead researcher Dr. Victor M. Elner, a professor in the University's Department of Ophthalmology and Visual Sciences.
"Our objective in performing this study was to determine whether we could detect abnormal metabolism in the retina of patients who otherwise would remain undiagnosed based on clinical examination alone," Dr. Elner adds.
In the study, Dr. Elner's team measured FA levels in 21 people with diabetes and compared those results with data from people who did not have the disease.
Study participants with diabetes had significantly higher levels of FA compared with those without diabetes, the researchers report. "The diabetics demonstrated consistently abnormal metabolism when compared to the control individuals without disease," Dr. Elner says.
His group also measured FA levels in patients with and without diabetic retinopathy.
"Patients with retinopathy had significantly more abnormality to their readings than patients without retinopathy," Dr. Elner reports. "This indicated that we can actually use the method to monitor the severity of the disease."
FA Testing has Benefits
The FA testing device takes a specialized photograph of the eye and is non-invasive, taking about five minutes to test both eyes
There are a number of advantages to FA testing, says Dr. Elner. "FA testing is less invasive, rapid, and gives a test result within five minutes. It complements glucose tolerance testing in that it actually tells us about tissue dysfunction in the retina, which is indicative of how the whole body is doing."
In addition, because of its rapid, noninvasive nature, the new test can be used to screen patients at risk for a variety of different diseases, Dr. Elner says. "Diabetes is the best example of that because of the prevalence of the disease in our population. But the technique is also capable of screening other diseases such as glaucoma or age-related macular degeneration," he adds.
Dr. Elner has a financial interest in this technology, and started a company with his research partner, Howard R. Petty, Ph.D., to make it commercially available.
Diabetes Not Always the Culprit in Eye Disease
The researchers note that elevated FA does not always mean that an individual has diabetes. "Because of the prevalence of diabetes in our population, individuals with abnormally high FA would be prompted to undergo glucose tolerance testing," says Dr. Elner. "If the findings were negative for diabetes, we would look for other causes of ocular tissue dysfunction."
Both Dr. Elner and Dr. Petty agree that the device has great potential as a tool for diabetes screening and management. "So much damage occurs before the disease can be detected by a doctor," comments Dr. Elner. "Early diagnosis will allow us to reduce organ damage and prevent many complications that accompany this disease."
Always consult your physician for more information.
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Eye Problems Associated with Diabetes
Diabetic eye disease refers to a group of eye problems that may occur in persons with diabetes as a complication. All can cause severe vision loss or even blindness. Diabetic eye disease can often be treated before vision loss occurs. All people with diabetes should have a dilated eye examination at least once a year.
Diabetic eye diseases include the following:
Diabetic retinopathy is the most common eye disease in persons with diabetes.
Diabetic retinopathy is a leading cause of blindness in American adults. It is caused by changes in the blood vessels of the retina. In some people with diabetic retinopathy, retinal blood vessels may swell and leak fluid, while in others, abnormal new blood vessels grow on the surface of the retina. These changes may result in vision loss or blindness.
Diabetic retinopathy cannot be completely avoided, but the risk can be greatly reduced. Better control of blood sugar level slows the onset and progression of retinopathy and reduces the need for laser surgery for severe retinopathy.
A person with an early stage of diabetic retinopathy may be asymptomatic and without pain. Vision may not change until the disease progresses.
A condition called macular edema may occur when the macula, a part of the retina, swells from the leaking fluid and causes blurred vision. When new vessels grow on the surface of the retina, they can bleed into the eye, blocking vision.
Anyone with diabetes is at risk for diabetic retinopathy. The longer a person has diabetes, the more likely he/she will develop diabetic retinopathy.
Always consult your physician for more information.
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