LASIK Laser Eye Surgery Articles from
San Francisco Vision Specialist Dr. Gary Kawesch

Therapeutic LASIK: A Case Report
Gary M. Kawesch, MD - Exclusive to EyeWorld

Phototherapeutic keratectomy is a valuable technique for treating corneal opacities, but its usefulness is limited to the anterior cornea. Traditionally, deeper scars have required lamellar or penetrating keratoplasty. I recently had an interesting case. A 26-year-old patient underwent hyperopic automated lamellar keratoplasty in September 1994, by another surgeon. His preoperative refraction was +4 +1.25 x60 right eye and +3.5 +3 x107 left eye, with best-corrected acuity of 20/20 in each eye. Surgery in the left eye was uneventful, but in the right eye the surgeon created a free cap, inadvertently replaced it inside-out (epithelium against stromal bed) and sutured it in place. Four days later, the surgeon realized his error when the free cap would not epithelialize well; he took the patient back to the operating room, removed the cap and replaced it properly. I first saw the patient for a second-opinion consultation several days after this second surgery. I noted extensive epithelial ingrowth, and recommended immediate removal, which was performed without incident.

After 6 months, the patient had uncorrected vision of 20/60 in the right eye, and with a refraction of +2 +3.75 x75, corrected only to 20/50. A dense haze was noted in the interface, and keratometric mires were distorted. The patient underwent a traditional surface excimer PTK in July 1995 at the Jules Stein Eye Institute, University of California, Los Angeles, but had no improvement in best-corrected vision. A trial of a rigid gas-permeable contact lens provided vision of only 20/50. Pinhole acuity was no better. The patient understood his only traditional option to rehabilitate vision would be lamellar or penetrating keratoplasty. I discussed with the patient a unique, but completely unproven, technique to improve his vision. If it failed, keratoplasty could still be performed. The proposed procedure was an intrastromal PTK. A deep keratectomy would be performed using the Chiron Automated Corneal Shaper, creating a flap to access the plane of scarring. An excimer laser, using PTK mode with a beam diameter of cleared 5 mm, would then be used to ablate the stromal bed and the undersurface of the flap.

I performed this procedure in April 1996 with a 400-,um plate and a 5.6-mm lens, setting the keratome stop to leave a very small hinge. Eleven microns of tissue were ablated from the bed and 7 um from the flap's undersurface. The flap was replaced without sutures. Five days postop, he was 20/2' uncorrected, refracting to 20/20 with +1.25 +1 x120. Two months postop, he was 20/30+, refracting 20/25 with +1.5 sphere. Postoperative slit lamp photographs reveal a clearing of much of the central, deep haze.

Iatrogenic keratoconus secondary to a deep lamellar cut, or hyperopic shift secondary to laser photoablation, are concerns with this approach, but a good result will save the patient from needing a much more invasive technique.

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