[Measurement of pupillary diameter in diabetic and non-diabetic patients: a case-control study]

To study the effect of type 2 diabetes on pupil diameter.

We carried out a case-control study at the Douala Obstetrics, Gynecology and Pediatric Hospital over a 5-month period. The cases were type 2 diabetic patients, and the controls were non-diabetic patients paired for age and gender. We studied the correlation between the duration of diabetes, fasting blood sugar and the horizontal pupil diameter.

We included 35 patients in each group. The mean age was 56.6±10.01 years. Both groups included 17 males and 18 females. The mean duration of diabetes was 2.72±4.31 years, and the mean fasting blood sugar was 2.02±0.69g/L. The mean pupil diameter was similar in the two groups. On the right side, it was 4.75±0.73mm for controls and 4.52±0.69mm for cases (P=0.179). On the left side, it was 4.70±0.68mm and 4.42±0.73mm respectively for each group (P=0.101). The duration of diabetes was correlated to pupil diameter in the right eye (r=-0.43; P=0.01) and left eye (r=-0.45; P<0.01). No additional risk was found to be associated with diabetes for right pupil diameters (OR=0.79; P=0.33), or for left ones (OR=0.76; P=0.24).

Pupil diameter is similar in diabetic and non-diabetic patients. However, the duration of diabetes appears to affect pupil diameter.