Corneal immune ring (CIR) appeared in the eyes of three patients who wore their extended wear contact lenses while sleeping. CIR's have not been reported as a complication associated with the wear of soft extended wear lenses. The CIR appeared within days of an episode of ulcerative keratitis with an infiltrative component. Treatment with topical antibiotic and anti-inflammatory agents produced resolution of the corneal lesions. The clinical appearance of the lesions as well as the time frame involved suggest that the immune response that produced the CIR was triggered by bacterial endotoxin through the properdin-mediated complement pathway.