Deposits of topical norfloxacin in the treatment of bacterial keratitis

Abstract

Purpose. Fluoroquinolone solutions are widely used in therapy of bacterial keratitis. These drugs are safe, and their ocular side effects are mild and not serious in nature. The most frequent untoward effect associated with ciprofloxacin therapy has been a white crystalline deposit. This deposit has not been reported after using the other commercially available quinolones, ofloxacin and norfloxacin. Methods. We present three cases of norfloxacin deposits after treatment of bacterial keratitis. Results. In the three cases, the norfloxacin was substituted for another antibiotic effective against the bacteria, and the precipitate spontaneously resolved in all cases within a few days with no untoward ocular effect. Conclusion. Crystalline corneal deposits can develop during topical norfloxacin therapy. The exact factors contributing to the formation are unknown, although the differences in the tear pH/solubility could be involved. Clinicians should be aware of this ocular side effect.