pH changes of the tear fluid in the conjunctival sac during postoperative inflammation of the human eye.

Conjunctival fluid pH was measured pre- and post-operatively in 16 patients suffering from senile cataract. We found a significant increase (P less than 0.05) from 7.26 +/- 0.23 (mean +/- SD) on the day before operation to 7.50 +/- 0.23 (mean +/- SD) on the first post-operative day in the conjunctival fluid of the treated eye. Thereafter a gradual decrease towards pre-operative level was observed. These changes were not observed in the healthy fellow eye (P greater than 0.05). No significant pre-operative difference was shown between the two eyes. It is reasonable to assume that the composition of the transudate/exudate from the conjunctival vessels might be responsible for the changes observed.