Light and electron microscopic study of the corneal stroma during the healing process of alkali-induced ulcer

Introduction:Corneal exposure to alkali is associated with defective clarity and impaired vision. Objective:This study was designed to describe structural and ultrastructural changes in the corneal stroma following alkali-induced ulcer. Materials and methods:Ten guinea pigs were anesthetized, and alkali burn was performed by touching a 4.0-mm-diameter applicator, a piece of sterile gauze, saturated with 1mol/l sodium hydroxide on the corneas of the left eyes for 30 seconds. The right and left eyes were harvested. Corneas from the right side were used as controls. H E-stained paraffin sections were prepared, and thin elongated strips from all the corneas were processed to be examined by transmission electron microscope. Results:Two weeks after alkali burn, corneal stromal neovascularization with the appearance of postcapillary venules was the most characteristic feature. This was associated with wide stromal spaces, inflammatory cellular infiltrate, activated fibroblasts, and irregularly deposited collagen. Conclusion:Despite corneal reepithelialization, stromal changes might account for defective clarity following exposure to alkali.