Wearable medical devices for the early detection of illness

A group of researchers in Taiwan has developed a new optical technology that may be able to detect an early complication of diabetes sooner, when it is more easily treated. If the device proves safe and effective in clinical trials, it may pave the way for the early detection and more effective treatment of diabetic autonomic neuropathy, which is common among people with Type 1 and Type 2 diabetes.

The condition progressively affects the autonomic nerves controlling vital organs such as the heart and gastrointestinal system. This can lead to fainting, incontinence, nausea, heart arrhythmias, an increased risk of bacterial infection, and similar problems.

The technology is a small, wearable device – called a pupillometer – that hangs on a pair of eyeglasses and weighs 78g, slightly heavier than Google Glass. Developed by a team at National Taiwan University Hospital, Hsin Chu branch, and National Chiao-Tung University, the device is designed to be worn for a half hour in the doctor’s office, during which time it would monitor a patient’s pupils. By carefully measuring parameters associated with the pupils, doctors may then be able to detect early signs of diabetic autonomic neuropathy.

Currently the condition is often not detected until moderate nerve damage and organ dysfunction are present.

Traditionally, doctors rely on observing changes in digestive speed, heart rate, and blood pressure to detect diabetic autonomic neuropathy, but this limits their ability to make an early diagnosis, says Mang Ou-Yang, who led the research with colleagues at National Chiao-Tung University. Now they have shown that monitoring the pupils of people with diabetes may be a better approach.

“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,” Ou-Yang explains.

The pupil is useful for detecting the diabetes complication due to the neurological conditions caused by the disease. As with many organs, the eyes and pupil are dually innervated, receiving signals from both the parasympathetic and sympathetic divisions of the autonomic nervous system. These divisions control the pupil’s circular and radial muscles, respectively.

The pupillometer emits four colored lights to stimulate the pupil. A beam splitter attached to the device then filters the visible light reflected from the eye to the device’s camera, which processes the images to analyze the pupil’s size.

The device measures 10 parameters related to pupil diameter and response time. Of those 10, the researchers found that five parameters were significantly different in people with diabetic autonomic neuropathy.

Ou-Yang says the pupillometer could be available by the end of the decade if clinical trials are successful.

Future research for Ou-Yang and his lab includes scaling down the size of the device, expanding the device’s capabilities to observe two pupils simultaneously, and collecting more experimental results from diabetic patients.

The Optical Society
www.osa.org