Surgically induced miosis (SIM) frequently occurs during extracapsular cataract extraction (ECCE). A randomized clinical trial was performed to evaluate the effect of 3 nonsteroidal antiinflammatory drugs Indomethacin 1%, Diclofenac 0.1% and Flurbiprofen 0.03%, administered topically before ECCE, on the maintenance of mydriasis during surgery. The patients were grouped based on the type of NSAID given preoperatively in addition to the standard mydriatic agents: 46 patients in group A (Indomethacin), 40 patients in B (Diclofenac), 44 patients in C (Flurbiprofen) and 34 patients formed control group D (no NSAID was instilled). Horizontal pupillary diameter measurements were taken, using a caliper, immediately prior to surgery (step 0), after capsulotomy (step I), after expression of the lens nucleus (step II) and after irrigation-aspiration of the cortical remnants (step III). Differences in pupillary diameter between step 0 and the different surgical steps were used as indices of pupillary constrictions observed in the 4 groups. A significantly less pupillary constriction was found in groups A and C than in D between steps 0 and II (p = 0.01) and in groups A and C than in B and D between steps 0 and III (p = 0.001). Our results show that Indomethacin 1% and Flurbiprofen 0.03%, compared to Diclofenac 0.1% and no NSAID regime, are significantly more effective in maintaining mydriasis during cataract surgery.