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July 1992

Unsuccessful Excimer Laser Phototherapeutic KeratectomyClinicopathologic Correlation

Author Affiliations

From the Doheny Eye Institute and the Departments of Ophthalmology (Drs J. McDonnell and P. McDonnell and Ms Garbus) and Pathology (Dr J. McDonnell), University of Southern California School of Medicine, Los Angeles. The authors and their family members have no financial or proprietary interest in any of the materials or methods described in this study.

Arch Ophthalmol. 1992;110(7):977-979. doi:10.1001/archopht.1992.01080190083034

• A 46-year-old man underwent phototherapeutic keratectomy with a 193-nm excimer laser in an attempt to remove a superficial corneal scar that had been present for 36 years. The scar proved to be resistant to ablation with the laser, while relatively normal stroma was easily ablated. Histopathologic examination of the corneal button removed 3 months after excimer laser surgery revealed absence of Bowman's membrane in the area of ablation, superficial stromal disorganization and scarring, raised nodules of collagenous tissue extending into the epithelium, and no calcification within the lesion. Ultrastructural examination was remarkable for irregularly oriented collagen fibers within the scar. The resistance of this lesion to excimer laser ablation appears to have been the consequence of marked differences in rates of ablation between normal stroma and the very longstanding scar.