Some aspects of ocular function after precurarization.

Small doses of nondepolarizing relaxants are often recommended as prior medication to suxamethonium in order to avoid or attenuate the side effects elicited by the latter drug. After D-tubocurarine (0.05 mg/kg b.w. and 0.075 mg/kg b.w.) in unmedicated volunteers, a dose-dependent recession of the monocular near point of accomodation was recorded. This recession, which parallelled the decrease in grip strength, was 4 cm and 9 cm, respectively. The same doses evoked an exophoria of 14 and 17 prism diopters, respectively. Intraocular pressure was significantly lowered by D-tubocurarine 0.05 mg/kg b.w., from 2.01 kPa (15.1 mmHg) to 1.64 kPa (12.3 mmHg), and by pancuronium 0.015 mg/kg b.w. from 1.90 kPa (14.3 mmHg) to 1.44 kPa (10.8 mmHg). The decreases lasted for 7 min. Gallamine 0.3 mg/kg b.w. also decreased intraocular pressure, but to a lesser degree, and with statistical significance only during the fourth minute after administration. Relaxation of extraocular muscles may change the slightly ovoid shape of the eyeball into a more spherical one, thereby inducing a fall in intraocular pressure and a recession of the near point of accommodation.