Increased corneal scarring after phototherapeutic keratectomy in Fuchs' corneal dystrophy.

PURPOSE: A 63-year-old female with Fuchs' endothelial corneal dystrophy, stromal edema and subepithelial scarring was inappropriately treated with phototherapeutic keratectomy, leading to a central focal circular corneal scar and decreased visual acuity that required penetrating keratoplasty. METHOD: The host corneal button was bisected and fixed in 10% formaldehyde and in glutaraldehyde immediately after its removal. RESULTS: Light microscopy demonstrated a central area of absent Bowman's layer with a thin layer of subepithelial fibrosis, stromal corneal edema, and thickened Descemet's membrane. CONCLUSION: Correct estimation of differential ablation rates of tissue and shallow, repeated ablations followed by slit-lamp microscopy and/or videokeratography help prevent over-treatment.