Diabetic autonomic neuropathy is a condition that can occur in both type 1 and type 2 diabetics, compromising the autonomic nerves that control the gastrointestinal system, the heart and other vital organs. Among other things, it can cause arrhythmias, fainting, incontinence and an increased risk of bacterial infections. Thanks to a device being developed in Taiwan, however, it may soon be possible to detect the condition earlier, thus limiting its effects.

Ordinarily, doctors look for diabetic autonomic neuropathy by tracking changes in a patient's digestive speed, heart rate and blood pressure. According to a team of scientists at National Chiao-Tung University and National Taiwan University Hospital, this approach often doesn't catch the condition until considerable damage to nerves and organs has already occurred.

Their system instead uses a small wearable device that hangs on a pair of eyeglasses, and which monitors changes in the size of the patient's pupils over a period of half an hour in a doctor's office. Known as a pupillometer, it stimulates the pupil by shining four colored lights into it (white, red, green, and blue), and then analyzes the light that's reflected back from the eye.

Using this technique, it measures 10 parameters relating to pupil diameter and response time. Five of those parameters are tellingly affected by diabetic autonomic neuropathy, due to the fact that the pupil's circular and radial muscles react in response to signals sent by the parasympathetic and sympathetic divisions of the autonomic nervous system, respectively.

A pupillometer testing setup, with the device on the left and an eye model on the right

"Compared to the existing diagnostic techniques, the pupillometer is a more reliable, effective, portable and inexpensive solution for diagnosing diabetic autonomic neuropathy in its early stages," said project leader Mang Ou-Yang, of National Chiao-Tung University.

The device is currently still in prototype form. It is hoped that once clinical trials are complete, it could be commercially available by the end of the decade.

A paper on the research was published yesterday in the journal Applied Optics.

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