PHOTOTHERAPEUTIC KERATECTOMY FOR GRANULAR AND LATTICE CORNEAL DYSTROPHIES AT 1.5 TO 4 YEARS

BACKGROUND: The capability of the 193-nm excimer laser to ablate the c ornea and to remove opacities and various other corneal diseases in a procedure called phototherapeutic keratectomy (PTK) has been demonstra ted, In this study we evaluated the long-term results of PTK for treat ment of granular and lattice corneal dystrophies. METHODS: Four eyes w ith granular or lattice corneal dystrophy were treated with a mean fol lowup of 47.8 months (range, 36 to 58 months). Focal ablations of the central cornea with an ablation zone of 5.5 to 6.0 mm were performed, Ablation depth was 110 mu m in three eyes and 140 mu m in one eye. RES ULTS: Removal of corneal opacities allowed for improvement in correcte d visual acuity in all patients. Mean corneal thickness in the area of pathology decreased from 0.583 mm before surgery to 0.449 mm after su rgery. Spherical equivalent of the manifest refraction measurements in creased by a mean of +5.09 D. There were no major complications, but a ll patients developed slight haze, There was a hyperopic shift in thre e eyes. CONCLUSION: Our long-term results suggest that PTK is a safe a nd effective alternative to penetrating and lamellar keratoplasty in p atients with granular or lattice corneal dystrophies.