[The autonomic pupillary dysfunction in type II diabetes mellitus].

OBJECTIVE

To evaluate the pupillary disorder associated with autonomic neuropathy of type II diabetes mellitus by investigating pupil diameters under mesopic, photopic and pharmacologically dilated conditions.

METHODS

Forty of type II diabetic patients were divided into two groups based on the results of fundus fluorescein angiography, one group was the subclinic diabetic retinopathy and another was the NPDR (nonproliferative diabetic retinopathy), 20 age-matched healthy subjects were selected as control. High-resolution images of the pupil in 60 subjects were taken using an infrared-sensitive camera under mesopic, photopic and pharmacologically dilated conditions, respectively. From the images, the pupil diameters, constriction ratio and dilatation ratio were analyzed using Photoshop, Acdsee, and Imagetools software.

RESULTS

The mean pupil diameter of tested subjects in mesopic control, subclinic and the NPDR were (6.02 +/- 0.48), (5.87 +/- 0.99), (4.95 +/- 1.12)mm, respectively. The mean photopic pupil diameter in three groups were (3.40 +/- 0.33), (3.37 +/- 0.31), (3.25 +/- 0.47) mm, respectively, where the mean pharmacologically dilated pupil diameter in three groups were (7.37 +/- 0.59), (6.91 +/- 1.00), (5.49 +/- 1.24) mm, respectively. The mean constriction ratio of these three groups were (43 +/- 7)%, (41 +/- 10)%, (32 +/- 14)%, respectively. The mean dilatation ratio of these three groups were (23 +/- 8)%, (19 +/- 13)%, (11 +/- 5)%, respectively. There were statistically significant differences among three groups in dark adapted pupil diameter, dilated pupil diameter, constriction ratio and dilatation ratio (P < 0.05).

CONCLUSIONS

Autonomic pupillary dysfunction occurs early in type II diabetic patients. Pupillary diameters under mesopic and pharmacologically dilated conditions, and other pupil changes such as constriction ratio and dilatation ratio can be the reliable sign to evaluate autonomic neuropathy of type II diabetes mellitus.