• In an experimental model of Pseudomonas keratitis produced by a gentamicin sulfate-resistant, tobramycin sulfate-sensitive strain of P aeruginosa, the results of two treatment regimens—(1) with gentamicin and tobramycin alone and (2) with gentamicin, tobramycin, and a steroid—were evaluated. All of the animals exhibited ultimately the same amount of corneal inflammation and corneal scarring. In the group receiving the antibioticsteroid combination, the corneal lesions healed more slowly.