Assessment of pupillary light reflex latency and darkness adapted pupil size in control subjects and in diabetic patients with and without cardiovascular autonomic neuropathy.

Increased pupillary light reflex latencies were found more often than a reduced darkness pupil size in diabetic patients with and without abnormal cardiovascular reflexes. This finding suggests that parasympathetic pupillary dysfunction precedes sympathetic pupillary denervation in diabetic autonomic neuropathy.