Cataract surgery and pupil size in patients with diabetes mellitus

Constriction of the pupil during phacoemulsification and intraocular lens (IOL) implantation in patients with diabetes mellitus was studied.

Before surgery a combination of 0.75% cyclopentolate and 2.5% phenylephrine was applied topically to the eyes of 32 patients with diabetes mellitus and 25 age-matched controls. Epinephrine was mixed with buffered saline solution and used during the surgery. The surgical procedure included capsulorhexis, phacoemulsification in the posterior chamber and implantation into the capsular bag of a heparine surface-modified poly(methyl metacrylate) IOL with an optic diameter of 5.0 mm. The durations of phacoemulsification and the whole surgical procedure were recorded. Measurements of the horizontal pupillary diameter were taken before surgery, after phacoemulsification and at the end of the surgery.

There was no significant difference in pupil size between controls and the diabetic group before the operation. Surgically induced miosis after phacoemulsification and at the end of operation were significantly more pronounced in the diabetic group than in controls (p < 0.05) (p < 0.05). Phacoemulsification and the entire surgical procedure took significantly longer time when performed in the diabetic eyes (p < 0.05) (p < 0.05).

We conclude from these data that constriction of the pupil during cataract surgery is more pronounced in diabetic eyes as compared to controls.