Guinea Pig Models of Acute Keratitis Responses

Purpose: Contact lens acute red eye (CLARE) and infiltrative keratitis (IK) are inflammatory responses of the eye associated with extended wear of soft contact lenses and are associated with bacterial colonization of contact lenses. Development of animal models to study these conditions is of importance in confirming risk factors and developing preventative strategies.

Methods: Silicone hydrogel contact lenses contaminated with a human CLARE isolate of Pseudomonas aeruginosa at inocula ranging from 1 x 10 to 6 x 10 colony-forming units (CFUs) for 15 minutes, 1 hour, or 24 hours were worn by guinea pigs for times up to 48 hours in 3 models designed to simulate contamination during wear and contact lens care regimens. Eyes were examined by slit-lamp biomicroscopy and histology to evaluate ocular responses and inflammation.

Results: Three different models for the effects of bacterial contamination on the etiology of CLARE/IK were developed and tested in the guinea pig eye. Bacterial contamination of contact lenses was confirmed to be a major risk factor for the development of CLARE/IK and a dose response shown. The pathological features of CLARE/IK in the guinea pig were virtually identical to those observed in human eyes.

Conclusion: The models characterized here provide a useful tool for development of interventional and therapeutic strategies for these important ocular inflammatory conditions.