Hooked onto glasses, small optical pupillometer aims to detect diabetic autonomic neuropathy sooner

A group of Taiwanese researchers has developed a wearable optical pupillometer that can automatically detect an early complication of diabetes (autonomic neuropathy, or damage to the involuntary nervous system) sooner, when it is more easily treated.¹

Diabetic autonomic neuropathy is common among people with both Type 1 and Type 2 diabetes. The condition progressively affects the autonomic nerves controlling vital organs like the heart and gastrointestinal system. This can lead to problems like fainting, incontinence, nausea, heart arrhythmias, and an increased risk of bacterial infection.

The new technology is a small, wearable device called a pupillometer that hangs on a pair of eyeglasses and only weighs 78 grams. Developed by a team at National Chiao-Tung University and the National Taiwan University Hospital Hsinchu Branch (both in Hsinchu City) and Chang Gung University (Taoyuan County), the device is designed to be worn for a half hour or so in the doctor's office, during which time it would monitor a person's pupils. By carefully measuring five parameters associated with the pupils, doctors may then be able to detect the earliest signs of diabetic autonomic neuropathy.

Four colors, two intensities

The pupillometer, which is small enough to be mounted onto the front of a pair of glasses, works by emitting light of four colors (white, red, green, and blue) and two intensities (50 and 500 mcd) to stimulate the pupil. A beamsplitter attached to the device then filters the visible light that is 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.

Currently 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 a diagnosis early on, said 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.

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

Source: The Optical Society (OSA)

REFERENCE:

1. Mei-Lan Ko et al., Applied Optics (2014); http://dx.doi.org/10.1364/AO.53.000H27