Sympathetic denervation of the iris dilator in noninsulin-dependent diabetes

Twenty-three subjects with noninsulin-dependent diabetes mellitus (NIDDM) and 23 age- and sex-matched controls were tested for sympathetic denervation of the iris dilator by comparing the mydriatic effect of the combination of 1% phenylephrine and 1% tropicamide with that of 1% tropicamide alone. Most of the diabetic subjects had no clinical signs of severe diabetic complications. Nine diabetics and two controls showed sympathetic denervation, defined as a 1 mm or greater dilation due the addition of 1% phenylephrine. One of those two controls had a recent history of vascular headache. The diabetics with pupillary neuropathy had higher glycosylated hemoglobin percentages and a history of higher fasting blood sugars (FBS's) than the diabetics with normal pupils. Our results show that pupillary neuropathy can develop in persons with diabetes, often before the other complications of diabetes become manifest.