SCANNING ELECTRON-MICROSCOPY OF THE EARLY HOST INFLAMMATORY RESPONSE IN EXPERIMENTAL PSEUDOMONAS KERATITIS AND CONTACT-LENS WEAR

Because contact lens were causes changes in tear film and corneal meta bolism and can render the cornea susceptible to bacterial invasion, we examined the role of contact lens wear in Pseudomonas aeruginosa (P. aeruginosa) keratitis and its relation to the early defense mechanism, specifically whether the acute polymorphonuclear leukocyte (PMN) resp onse is altered by contact lens wear. Thirty-three rabbit eyes were ex amined in an experimental model for P. aeruginosa keratitis. The devel opment of bacterial invasion and PMN migration into the wound was stud ied during various time intervals in either the presence or absence of a soft hydrogel contact lens (SCL). Scanning electron microscopy reve aled massive PMN accumulation in the P. aeruginosa-inoculated corneas without SCL and some, but distinctively fewer, PMNs in the bacteria-in oculated eyes with SCL. These observations demonstrate that P. aerugin osa inoculation evokes massive PMN reaction and suggests that SCL wear actually delays this early host inflammatory response. Thus, SCL wear seems to act as a barrier for the PMNs that presumably derive from th e tear film.