Case Report: Interstitial Keratitis in a Patient With Past History of Corneal Collagen Cross-Linking for Post-LASIK Keratectasia and Scleral Lens Wear

Introduction A 48-year-old female patient wearing scleral contact lenses presented with a 4-month history of blurred left vision 13 years after collagen cross-linking (CXL) for post-LASIK keratectasia. Slit-lamp examination demonstrated multiple midstromal fine refractile deposits in the nasal and temporal paracentral left cornea, without stromal inflammation, epithelial defect, or anterior chamber reaction. A penetrating keratoplasty was performed to improve vision, which remained clear at 5 months’ follow-up. Case Report Histopathology of the corneal donor button demonstrated interstitial keratitis: A stromal infiltrate of lymphocytes, scattered foamy macrophages, and activated keratocytes. There were no crystals. Two prior corneal biopsies for microbial and histological assessments were unremarkable. Blood test results for systemic conditions associated with interstitial keratitis, crystal, or protein deposition were negative. There was no improvement with an empirical trial of frequent topical fluorometholone acetate 0.1% (Flarex). With 6 months of abstinence from scleral lens wear, the deposits became less dense; however, after resumption of scleral contact lens wear, new refractile deposits reappeared. The donor cornea remained clear at 5 months’ postoperative follow-up. Conclusion This case of interstitial keratitis is unique because of the absence of a clear infectious etiology. Wear of scleral contact lenses was the most likely cause. Previous LASIK and cross-linking may have played a role; however, both were many years before this presentation. The role of omalizumab, an anti-immunoglobulin E therapy, remains unknown.