Autonomic Neuropathy and the Pathogenesis of Glaucoma in Diabetes Mellitus

In order to determine whether ocular hypertension and glaucoma may be a complication of autonomic neuropathy in diabetes mellitus, 30 asymptomatic diabetic patient volunteers were studied. A correlation was sought between reduced anterior chamber depth which is thought to predispose to the development of glaucoma, and two markers of autonomic dysfunction, loss of sinus arrhythmia and reduced diameter of dark adapted pupils. A significant correlation was found between reduced chamber depth and pupil diameter arrhythmia (r = 0.36, p = 0.025) and between chamber depth and pupil diameter (r = 0.45, p = 0.006). As expected, there was also a significant correlation between sinus arrhythmia and pupil diameter (r = 0.68, p less than 0.001). The correlation between pupil diameter and sinus arrhythmia, and between pupil diameter and chamber depth was preserved after the data were adjusted for age (r = 0.54, p less than 0.001 and r = 0.35, p = 0.03, respectively), while that between sinus arrhythmia and chamber depth was lost (r = 0.23, NS). No association was found between intraocular pressure and either marker of autonomic dysfunction, but intraocular pressure was not abnormal (less than 22 mmHg) in any individual case. These data suggest that autonomic denervation of the eye in diabetes may be associated with alteration of anterior chamber depth.