Halothane anesthesia and aqueous humor dynamics in laboratory animals.

Halothane anesthesia decreased intraocular pressure (IOP) by approximately 4 mm Hg in both normal rabbits and monkeys. The administration of nitrous oxide or 100% oxygen had no effect on IOP. Although PO2 and PCO2 increased following halothane administration in rabbits, similar blood changes occurred without IOP reduction in control rabbits receiving 100% oxygen. Outflow facility in both species as measured by tonography remained unchanged by halothane administration. Aqueous humor flow as estimated by tonography decreased by about 39% in rabbits and 31% in monkeys. Posterior chamber aqueous humor ascorbate was significantly elevated 90 min after halothane administration in rabbits. The ratio of the aqueous humor flow coefficient to diffusion coefficient for ascorbate (kfa/kdpa) was reduced approximately 47% following the administration of halothane. Halothane did not alter the in vitro accumulation of 131I-hippuran or 86Rb by rabbit ciliary body--iris preparations.