Early detection: Researchers recognize diabetic foot on the eye
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| diabetic-foot |
The diabetic foot leads to around 40,000 amputations per year. With a new method, ophthalmologists can detect the onset of the nerve at an early stage. Now researchers hope for a breakthrough with new drugs.
Deafness, tingling, pain, sensitivity to touch - the symptoms of creeping nerve breakdown, neuropathy, are manifold. They usually start in the toes and continue to rise above the lower legs. Around 1.5 million of the six million diabetics in Germany are affected by the loss of nerve in their legs. One in twenty develops an ulcer, a weeping, poorly healing wound.
Reversible, the damages of the so-called peripheral diabetic neuropathy are not. Recognized early enough, however, their progression can be slowed by better blood glucose control. Ophthalmology now promises a new method of early detection. The eye reflects nerve damage to the entire body. On his cornea (cornea) researchers can thus determine whether the creeping nerve breakdown has already begun.
"The cornea has the densest network of nerves in the body Studies in Germany have shown that in diabetic patients with no signs of neuropathy, the nerve fiber density of the cornea is already thinned," says Rudolf Guthoff, Director of the University Eye Hospital Rostock in the run-up to the annual meeting of the German Ophthalmologic Society (DOG) from 19 to 22 September in Berlin.
The ophthalmologist and a team of scientists have developed a microscopic procedure that increases the cornea 800 times over the past decade. The nerves and changes to it are so early visible. The investigation is in comparison to previous diagnostic methods inexpensive and painless for the patients, says Guthoff. These would only receive eye drops before the microscope is briefly placed on the surface of the eye to measure the nerve fiber braid of the cornea. If fibers have died, this indicates an incipient neuropathy, the scientists found.
Where does the nerve damage begin?
Diabetologists confirm that corneal diagnostics are suitable for the early detection of diabetic foot. "In a previously unpublished study, we were able to detect an early onset in the cornea of diabetics," says Dan Ziegler, Deputy Director of the Institute for Clinical Diabetology at the German Diabetes Center in Dusseldorf.
The study involved 86 predominantly type II diabetics with a mean age of 57 years. The disease had been diagnosed two years earlier. Only eight percent of the subjects already had signs of nerve damage. "Although the patients were well-adjusted with a blood glucose long-term value of 6.8 millimoles per liter, we found a 20 percent drop in fiber," says Ziegler, "even in some who have not had any symptoms so far."
However, the study provided no clear evidence that neuropathy necessarily begins in the eye. "In 17 percent, we found nerve damage to the cornea and 18 percent of the lower legs," explains the neuro diabetologist. But these were not the same patients. According to Ziegler, the neuropathy of the small fibers can begin at different points. "In some subjects of the study, it started in the eye, in others on the leg and only in a minority in both places at the same time," he sums up the result - questioning the benefit of the corneal method for all diabetic patients.
Compared to other non-operative procedures, however, the advantage of early detection is undisputed, according to Ziegler. Conventional examinations of the sensation of pain, contact, temperature, and vibration on the legs only indicate damage to the nerves when there are already clear symptoms, ie the disease has already progressed. Diagnosis at an early stage allowed only painful and costly tissue sampling or measurement of nerve conduction velocity. However, these indicate only large fiber damage, explains the neuro diabetologist.
The question remains, what patients have from early detection? In Germany, only a few specialized university eye clinics are still available for research purposes, for example in Düsseldorf, Munich, and Homburg (Saarland). The onset of nerve damage can be a warning to the patient. In addition, the corneal examination offers the opportunity to check the effectiveness of neuropathic drugs.
"A preparation that could cure a neuropathy would be a real breakthrough," says Ziegler. In his opinion, however, it is still a "long way" until the regeneration of the nerves can be detected with the help of the new diagnostics.