The effects of atracurium on intraocular pressure (IOP) were compared with those of pancuronium in 20 patients less than 45 years-of-age requiring surgery for trauma of one eye. After a standard premedication and the application of topical analgesia to the upper airway, anaesthesia was induced with thiopentone i.v. and the trachea was intubated without the use of neuromuscular blockade. Following 20 min of steady state anaesthesia during which measurements of IOP, arterial pressure, heart rate, FIO2, FE'CO2 and CVP were recorded, one group of patients received atracurium 0.45 mg kg-1 and the other pancuronium 0.1 mg kg-1. The observations were repeated for a further 15 min before surgery commenced. Neither atracurium nor pancuronium produced any change in IOP. Atracurium was associated with greater cardiovascular stability than pancuronium.