Background: Staged keratotomy surgery, or "enhancement surgery," may allow a more predictable outcome, but also subjects the patient to additional surgical risks.
Methods: A 39-year-old man underwent astigmatic keratotomy for myopic astigmatism, followed by 12 enhancement procedures for residual astigmatism.
Results: These procedures effectively resulted in a double hexagonal keratotomy. The patient's best spectacle-corrected acuity deteriorated to counting fingers. Clinically, a conically-shaped protrusion of the central cornea, Munson's sign, diffuse subepithelial scarring, and central corneal thinning were noted. Penetrating keratoplasty was performed. Histopathologic examination showed central thinning, epithelial edema, disruption of Bowman's layer, marked stromal scarring, and focal areas of endothelial attenuation--findings consistent with keratoconus.
Conclusion: This case illustrates that multiple keratotomy procedures may result in corneal ectasia in apparently normal eyes and suggests that hexagonal keratotomy may be more likely to cause iatrogenic keratoconus.