The effect of 1% apraclonidine on intraocular pressure after cataract surgery

To measure the effect of 1% apraclonidine hydrochloride eyedrops on intraocular pressure (IOP) after cataract surgery. The effects of two different dosage regimens, once before surgery or once before and after surgery, were studied.

Patients scheduled for extracapsular cataract extraction and artificial lens implantation were randomly assigned to three groups: group A had a placebo treatment (n = 18), group B had one drop of 1% apraclonidine 1 hour before surgery (n = 16), and group C had one drop of 1% apraclonidine 1 hour before surgery and 1 drop at the end of surgery (n = 17). Two percent hydroxy-propyl-methyl-cellulose was used as the viscoelastic substance. The preoperative IOP and the IOP 6 hours postoperatively in each patient were compared. The paired Student's t test was used to compare IOP before and after surgery. The study design was a randomly assigned, double-masked controlled clinical trial.

In group A (placebo) and group B (apraclonidine before surgery), there was a significant increase in IOP (mean IOP increase 11.2 +/- 9.9 mm Hg SD, range -4 to 32, P = .00017, and 9.4 +/- 7.4 mm Hg SD, range -3 to 24, P = .00014, respectively). In group C (apraclonidine 1 hour before and immediately after surgery), the increase in IOP was not significant (mean IOP increase 5.1 +/- 11.5 mm Hg SD, range -10 to 28, P = .084). A postoperative IOP of more than 40 mm Hg applanation tension was reached by two patients in group A, one patient in group B, and two patients in group C.

Although 1% apraclonidine eye-drops instilled 1 hour before and immediately after extracapsular cataract extraction with artificial lens implantation may help prevent a statistically significant increase in IOP after the operation, 2 of the 17 patients still had IOPs greater than 40 mm Hg 6 hours postoperatively. Apraclonidine applied only before surgery did not prevent a statistically significant increase in IOP.