ABSTRACT
The intra ocular pressure in both eyes of 23 patients undergoing open heart surgery, was measured by Schiotz indentation tonometer before, during and after the surgery until it returned to the pre operative levels. It was observed that a marked and rapid drop of the IOP occurs during the operation time, reaching its minimum during the cardio-pulmonary by-pass [[PB] period, then it gradually rises to its normal pre operative levels in 69.5% of cases [16 out of 23] at the end of the first post operative day, in 91% of cases [21 out of 23] at the end of the second post operative day and in all cases [100% of cases] at the end of the third post operative day. The possible explanations for such changes were discussed in view of the anaesthetic agents, techniques and associated hemodynamic parameters