Thirty healthy patients were studied to evaluate the effect of muscle relaxants on intra-ocular pressure (IOP) during anesthesia. The patients were divided intro three groups-succinrlcholine group(Img/k7,n=10) , pancu-ronium group(0.08mg/kg,n=10), and vecuronium group(0, Img/kg,n=10) according to the muscle relaxants used. All patients were premedicated with robinul 0.2mg and lorazepam 4mg one hour before surgery. Tracheal intubation was fellowed by thiopental sodium 5mg/ kg and muscle relaxant. Anesthesia was maintained with O2-N2O-enflurane and respiration and was controlled by anesthetic ventilator (Dameca). The lOP was measured hy Schotz tonometer, before induction of anesthesia, at 75~100% depression of twitch height on train of-four after injection of muscle relaxant, and at 1,3, 5, 10, minutes after intubation respectively. Heart rate, mean arterial pressure, and end-tidal CO2 tensions were also measured simultaneously. The results were as follows ; 1) At 75~100% depression of twitch height, IOP wart elevated significantly in succinylc-holine group but reduced significantly in both pancuronium and vecuronium groups as Compared With pre induction value. 2) IOP was elevated in all groups after 1 minute of intubation, there were no statistical significance in pancuronium or vecuronium group as compared with pre induction value. After 3 minutes of intubation, IOP was reduced in all groups in proportion to the depth of anesthesia. 3) Cardiovascular changes in vecuronium group were less than those in succinrlcholine or pancuronium group. In conclusion vecuronium, with less cardiovascular changes, may be indicated for anest-hesia of open eye injury compare other muscle relaxants.