Prevention of stromal ulceration in the alkali-burned rabbit cornea by glued-on contact lens. Evidence for the role of polymorphonuclear leukocytes in collagen degradation.

Stromal ulceration of the alkali-burned rabbit cornea was found to be associated invariably with phagocytically active polymorphonuclear leukocytes (PMNs). A glued-on methylmethacrylate lens applied to corneas soon after burning, however, prevented re-epithelialization and also prevented PMN infiltration of the stroma and stromal ulceration. Subsequent partial detachment or complete removal of the lens resulted in epithelial resurfacing of the stroma, PMN infiltration, and stromal ulceration. Glued-on lenses applied to already ulcerating corneas arrested further ulceration by prohibiting additional PMN infiltration. Either surface debridement or glued-on methylmethacrylate rings also prevented re-epithelialization and ulceration in stromas not infiltrated by PMNs, but neither treatment was sufficient to prevent ulceration in corneas already containing numerous PMNs. The data suggest the possibility that the epithelium stimulates infiltration of the stroma by PMNs which then participate in stromal matrix degradation. Although no claim is made that only PMNs mediate matrix destruction in corneal ulceration, the efficacy of the lens would seem to be due to exclusion of the epithelium and the consequent prevention of stromal infiltration by PMNs.