Long-term results of phototherapeutic keratectomy for corneal map-dot-fingerprint dystrophy (Cogan-Guerry)

Purpose: Patients with corneal map-dot-fingerprint dystrophy suffer typically from recurrent corneal erosion, disturbed vision, or both. The purpose of this study was to assess the morphologic and functional long-term results of minimal invasive subepithelial phototherapeutic keratectomy (PTK) for corneal map-dot-fingerprint dystrophy. Methods: Of a total of 390 PTKs performed between October 1994 and January 2004, 15 PTKs on 15 eyes of 11 patients were included in this single-center study All patients had symptoms of recurrent corneal erosion; in 12 eyes, reduced visual acuity was observed. The median duration of complaints was 18 months. Using 193-nm excimer laser (MEL 60/70; Carl Zeiss-Meditec), a manually guided spot profile was applied in 7 cases (pulse energy, 12 mJ; repetition rate, 2/s or 3/s; 189-425 pulses). In 8 cases, a scanning slit mode was chosen (intended ablation, 1 mu m/scan; repetition rate, 20/s; 150-483 pulses). In each case, a broad deepithelialization of the Bowman layer was followed by application of defocused overlapping laser pulses. Results: Complete epithelial closure was achieved after an average of 3.5 +/- 0.6 days (median, 3 days). The mean follow-up was 4.8 +/- 3.0 years, with a maximum of 9.3 years. Best corrected visual acuity increased from 0.7 +/- 0.26 preoperatively to 0.9 +/- 0.16 postoperatively. The keratometric central power remained constant (preoperatively, 43.0 +/- 1.6 D; postoperatively, 42.6 +/- 1.0 D). The average keratometric astigmatism remained constant (1.3 +/- 0.9 D, preoperatively; 1.0 +/- 0.5 D, postoperatively). In the early postoperative stage, subtle superficial corneal opacities ("haze") were observed in 6 eyes (40%), being completely reversible during the follow-up in 5 cases. No recurrence of corneal erosion was observed during the follow-up. Asymptomatic dystrophic signs in the midperiphery became visible in 2 eyes 3 and 5 years after PTK. Conclusion: For corneal map-dot-fingerprint dystrophy, PTK using an excimer laser with low pulse energy and low number of pulses can be considered an effective and minimal invasive treatment modality to achieve a fast and durable epithelial closure, to prevent recurrent corneal erosions, and to increase visual acuity in most patients.