Alkali-burned eyes (45 sec, 12 mm, 4N NaOH) were subjected to topical treatment with 10% ascorbate, 20% acetylcysteine, 10% ascorbate together with 20% acetylcysteine, 10% citrate, or Adsorbotear vehicle. Only citrate-treated eyes showed a significant decrease in corneal ulcerations and perforations (17%) compared with ascorbate (88%), acetylcysteine (81%), ascorbate/acetyl-cysteine (100%), or Adsorbotear (75%). In the citrate-treated eyes there was a significantly reduced incidence of band keratopathy (17%) but an increased incidence of hyphema (100%). Both groups receiving acetylcysteine developed acellular corneal caps, the result of peripheral ulceration undermining the central cornea. Polymorphonuclear neutrophils (PMN) were substantially increased at the base of the cap in the acetylcysteine- and acetylcysteine/ascorbate-treated eyes at day 56. At the end of the experiment, citrate-treated eyes showed substantially fewer stromal PMN than any other group. These results show that topical citrate has a most favorable effect on the incidence of corneal ulceration and perforation after alkali burning.