Hydrogel contact lens-induced Pseudomonas keratitis in a rabbit model.

Unused soft contact lenses (SCL) containing 38.6% water (polymacon) and 70% water (lidofilcon A) were exposed to Pseudomonas aeruginosa (10(8) CFU/ml) for 60 min and washed. The contaminated lenses were used on rabbit eyes under the following conditions: for 1 h on a scratched corneal epithelium (16 eyes, four infected), for 24 h on normal cornea (eight eyes, none infected), and for 7 days on normal cornea (eight eyes, three bacterial infections and two noninfected epithelial defects). A control group of rabbits used an uncontaminated lens for 7 days (eight eyes, four noninfected epithelial defects). The control group and groups that wore contaminated lenses for 24 h and 7 days underwent tarsorrhaphy to keep the contact lens in place. In addition, three drops of the bacterial suspension were instilled in eyes with normal corneal epithelium (eight eyes, none infected) and scratched corneal epithelium (16 eyes, 13 infected). Results suggest that Pseudomonas-contaminated SCL give rise to keratitis only on an injured corneal epithelium and that a bacterial suspension is more pathogenic to the rabbit cornea than is a similar amount of bacteria on an SCL.