·AIM:To investigate if pilocarpine can effectively prevent the acute increase of intraocular pressure(IOP)in brown eyes after Nd∶YAG laser iridectomy.·METHODS:Totally 48 cases 58 eyes with primary angle-closure glaucoma were divided into treatment and control groups,which were matched by age and sex.One drop of pilocarpine was applied into the conjunctival sac at one hour before laser iridectomy and immediately after laser iridectomy in treatment group,whereas one drop of antibiotic as placebo was applied in control group at the same time.IOP,pupil diameter were measured at 0.5,1.0,1.5,2.0,3.5 hours after laser iridectomy.·RESULTS:The maximum increase of IOP after laser iridectomy was 0.62±0.67kPa and 1.13±0.87kPa in treatment and control group respectively,there was a significant difference(P=0.03).The obvious decrease of IOP occurred at 0.5,1.0 and 1.5 hours after laser iridectomy in treatment group.No ocular and systemic side effects were found in treatment group,except pupil diameter was obviously larger in treatment group than that in control group.·CONCLUSION:20g/L pilocarpine can effectively prevent the acute increase of IOP in brown eyes after Nd∶YAG laser iridectomy.·