Irrigating solutions for intraocular purposes were evaluated for their possible damaging effects on the corneal endothelial cell structure and function. Rabbit corneal endothelium was perfused in vitro with Tis-u-Sol, Travenol Ringer's Solution, or Travenol Sodium Chloride. The irrigating solutions caused an immediate corneal swelling of 67 mum per hour +/- 5 (mean +/- standard error), which was not modified by a previous stabilization perfusion with glutathione-bicarbonate Ringer's (GBR). In contrast, the Plasma-lyte-148 solution which is used in the phacoemulsification procedure, did not cause corneal swelling for more than twenty minutes, and for more than sixty minutes if the cornea was perfused after a GBR stabilization. After more than sixty minutes of corneal swelling, endothelial intercellular junction separations appeared. This breakdown was present with the tested irrigating solutions except for Travenol Ringer's Solution, which contained calcium. Plasma-lyte was also evaluated in conjunction with the surgical phacoemulsification procedure. The complete procedure or just irrigation with ultrasound did not cause endothelial cell damage similar to a prolonged in vitro irrigation. Instead, endothelial cells were traumatically damaged in varying degrees by the surgical manipulations.