Some aspects of waterloadings in rabbits.

The effect of various amounts of waterload and the differences caused by oral and parenteral administration of fluids on the intraocular pressure (IOP), pupil diameter and blood osmolality were investigated. Trained rabbits were given loadings of fluids by different routes. An oral waterload of 100 ml/kg bodyweight gave an elevation of the IOP of about 12 mm Hg. Smaller amounts give a less pronounced IOP elevation. Intraperitoneal administration does not seem to increase IOP markedly. Rapid infusion of glucose 5% 15 ml/kg produces a transient and modest increase of the IOP. The mechanisms by which oral waterloading increases the IOP are discussed.