Design and analysis of wearable pupillometer for autonomic neuropathy of diabetic patients

Abstract

Diabetes is a familiar disease in modern society. In the early stage of diabetes, symptoms are unobvious, but they usually induce diabetic autonomic neuropathy or, worse, cardiovascular autonomic neuropathy. Pupillometers are effective instruments for observing human pupils. This article presents a novel wearable pupillometer design, without external light artifacts, and an embedded algorithm with blinking elimination, which investigates autonomic neuropathy through recording pupil dynamics triggered by an external sensitive invisible light source. The pupillometer is experimented on 36 healthy subjects and 10 diabetic patients under four different colors (white, red, green, and blue) as well as two different light intensities: 50 and 500 mcd. Ten parameters derived from pupil diameter, pupil response time, and pupil response speed will be evaluated for the healthy subjects and diabetic patients. The results show that three in four parameters related to pupil diameters, one in four related to light intensities, and one in two related to pupil response speed could have significant differences (p<0.05) between healthy subjects and diabetic patients. These parameters obtain over 85% sensitivity, 83% specificity, and 88% accuracy. The pupillometer is proven reliable, effective, portable, and inexpensive for diagnosing diabetes in an early stage.

Relation of Pupil Size and retinal diseases

“…There was a significant smaller pupil size at scotopic and mesopic illumination conditions at the DM-group in comparison to AMD, RVO and the control group. This is consistent with previous studies [4,7,8].…”

“…The Parasympathetic and sympathetic pupillary dysfunction appears to be a common feature of autonomic impairment in diabetes mellitus [3] and is evidenced by diminished amplitude reflexes and significant smaller pupil diameter [1]. Furthermore, Ko et al, showed that the pupillary diameter is related to poor metabolic control, long diabetes duration, and also to other indices of microvascular diseases in patients with diabetes [4].…”

“…Therefore an early detection is essential to enable appropriate interventional therapy and management [5]. The pupillometer is proven reliable and effective for diagnosing diabetes in an early stage [4].…”

Effect of neuropathy on pupillary response measured with infrared static pupillography in type 2 diabetes mellitus patients

“…The American Diabetes Association recommends that neuropathy screening is performed every five years after diagnosis in Type 1 Diabetes Mellitus patients, and every year after diagnosis in Type 2 Diabetes Mellitus [5]. Therefore, it is not often expected to be affected by pupillary responses even in the absence of polyneuropathy in a population with an average of 4 years of diabetes.…”

Efficient organic photomemory with photography-ready programming speed

“…Recent advances in organic electronics have proven their significance and competence in optoelectronic applications 1 2 3 4 5 6 . In particular, organic photosensors have been regarded promising due to their numerous potential applications in image sensing 7 8 9 , optoelectronic communication 3 4 5 6 , and health care monitoring 10 11 12 13 . They have been developed with various structures and operating mechanisms 14 such as photoconductors 15 16 , photodiodes 17 18 19 , phototransistors 20 21 22 , and photomemories.…”