This patient with recurrent erosion syndrome and a history of anterior stromal puncture followed by subsequent PTK presents with 20/300 UDVA, 3+ central corneal haze, and a hyperopic refraction. Haze rarely develops after PTK for recurrent erosion syndrome because the ablations are superficial (5 to 7 μm) unless reepithelialization after the treatment was extended because of factors such as dry eye. The refraction and pachymetry before PTK are not given.
Assuming they were the same as in the fellow eye, it appears that the ablation was 40 to 50 μm, which is consistent with a postoperative 4.00 diopter (D) hyperopic shift in the right eye and corneal topography findings of a well-centered ablation. Review of the patient's treatment records would be helpful.
Because the patient had previous anterior stromal puncture and subepithelial corneal scarring, activated keratocytes were likely present, increasing the risk for postoperative haze. To manage this case, I would discuss the situation with the patient and emphasize that haze reduction rather than the refractive outcome would be the goal. Also, I would emphasize that the corneal haze may recur. I would optimize the anterior ocular surface with lubricants, temporary plugs, and topical cyclosporine (if required) before treatment to ensure rapid reepithelialization of the cornea. Next, I would perform a superficial keratectomy to remove the central 9.0 mm of corneal epithelium and irregularly elevated scar tissue. After superficial keratectomy, I would treat 50% to 65% of the refraction and apply MMC 0.02% for 60 seconds. The 60-second application is based on a literature review (not published) I performed last year of MMC treatment in eyes with pathologic corneal haze. In many cases with pathologic corneal haze after excimer laser treatment there is corneal flattening, resulting in a hyperopic shift; however, the data given here suggest that the patient received a deep PTK ablation. I never treat the full correction; my limit is 50% to 65% of the refraction because scar removal can greatly affect the refractive outcome. Another reason for the reduced treatment is the MMC application; however, the amount of treatment reduction varies by surgeon.
At the end of the procedure, I would place an extended-wear contact lens to facilitate corneal epithelialization; the contact lens would be worn until the corneal surface is fully reepithelialized. A slow steroid taper (over 2 to 3 months) would be prescribed to modulate haze formation in the postoperative period; I would also ask the patient to take oral vitamin C (500 mg 2 times a day 1 week before the procedure and for 2 weeks after) and use sunglasses to protect against ultraviolet light. Topical cyclosporine would be continued in the postoperative period.