A Simple Diagnostic Test for Pupillary Abnormality in Diabetic Autonomic Neuropathy

Abstract
A simple portable pupillometer using Polaroid photography has been developed for use in the diagnosis of diabetic autonomic neuropathy. The pupil diameter per cent (PD%), defined as the percentage of iris diameter to which pupil diameter had dilated in darkness, was measured from the instant colour prints. An age‐related normal range was constructed from measurements in 163 healthy subjects in whom PD% declined linearly by 3% per decade. The PD% was measured in 15 patients with automatic neuropathy and 12 were identified with abnormally low values indicating a failure of sympathetically mediated dilatation. Results were consistent with the standard television pupillometric technique and had the same high repeatability with a coefficient of variation of 3.2%.