Excimer laser phototherapeutic keratectomy. Surgical strategies and clinical outcomes.

PURPOSE

To assess the different strategies and analyze clinical outcomes of excimer laser phototherapeutic keratectomy (PTK) for a variety of superficial corneal disorders.

METHODS

Twenty-eight eyes of 26 patients with one of five general categories of corneal disorders were treated with a variety of PTK techniques. Patients were assessed for preoperative and postoperative corneal thickness, uncorrected and best spectacle-corrected visual acuity, refractive changes, corneal topography and astigmatism, and results of a subjective patient questionnaire. Follow-up ranged from 6 to 30 months.

RESULTS

The average number of laser pulses was 418, with a mean decrease in corneal thickness of 31 microns. Uncorrected visual acuity improved in 20 eyes and decreased in 5. Best spectacle-corrected visual acuity improved in 20 eyes and decreased in 5; two patients had two Snellen lines of best-corrected vision loss. Nineteen patients (21 eyes) noted symptomatic improvement. Corneal topography improved in 17 eyes and worsened in 1. The average refractive shift was +1.4 diopters; patients undergoing general PTK, PTK combined with mechanical superficial keratectomy, and superficial scar removal had greater degrees of hyperopic shift. Complications were rare. Two patients who did not appreciate adequate improvement in vision after PTK underwent subsequent penetrating keratoplasty.

CONCLUSIONS

A number of PTK techniques are available to treat particular corneal disorders. Planning of surgical strategy is guided by careful patient selection which will minimize optical side effects and optimize visual outcome and subjective symptomatology after the PTK procedure.