Contact lens-induced peripheral ulcers with extended wear of disposable hydrogel lenses: Histopathologic observations on the nature and type of corneal infiltrate

Purpose. Contact lens-induced peripheral ulcer (CLPU), a sudden-onset adver se event observed with extended wear of hydrogel lenses, is characterized b y a single, small, circular, focal anterior stromal infiltrate in the corne al periphery or mid-periphery. The condition is always associated with a si gnificant overlying epithelial loss and resolves in a scar. The aim was to determine, by using histopathologic techniques, the nature and type of the corneal infiltrate of these events. Methods. Three CLPUs observed in three patients using disposable hydrogel lenses on an extended-wear schedule were examined. The eye was topically anesthetized, and a corneal section includ ing all of the infiltrate was taken. A small triangular piece of conjunctiv a immediately adjacent to the infiltrate was sectioned. The tissue was imme diately fixed, processed, stained using hematoxylin and eosin and periodic acid-Schiff stains, and examined by using light microscopy. Results. The di ameter of these three corneal infiltrates varied from 0.3 to 0.6 mm. Histop athology of the corneal sections revealed a focal epithelial loss correspon ding to the infiltrated stroma in all three patients. The adjacent epitheli um was thinned. Bowman's layer was intact in two patients and had a localiz ed area of loss in the remaining patient. The anterior stroma was densely i nfiltrated with polymorphonuclear leukocytes and had focal areas of necrosi s. The infiltration was most dense in the region immediately underlying Bow man's layer. No other infiltrative cell type was seen in any of the section s. Histopathology of the conjunctiva revealed features consistent with norm al conjunctival tissue. Conclusions. On histopathology of CLPU, distinctive features (i.e., focal corneal epithelial loss, an intact Bowman's membrane , and a localized infiltration of the anterior stroma with polymorphonuclea r leukocytes) were seen. These features suggest that the event is an acute inflammatory process and probably noninfective in nature.