Apical nodular subepithelial corneal scar after retreatment in hyperopic photorefractive keratectomy

To report a complication, apical nodular subepithelial corneal scar, that c an occur after hyperopic photorefractive keratectomy (PRK) retreatment. Setting: Istanbul University Eye Research Center, istanbul, Turkey. Methods: Twelve eyes of 6 patients with apical nodular subepithelial cornea l scar were retrospectively studied. Mean age of the 5 men and 1 woman was 30.2 years +/- 5.4 (SD). All eyes had hyperopic PRK retreatment for regress ion 9.5 +/- 1.44 months after primary hyperopic PRK. Mean spherical equival ent refraction of the residual hyperopia before retreatment was +4.67 +/- 0 .81 diopters (D). All patients had a corneal haze grade of less than 1+. Hy peropic PRK retreatment was performed with a 193 nm excimer laser (Chiron T echnolas Keracor 116). Results: Apical nodular subepithelial corneal scars developed within the fi rst month of hyperopic PRK retreatment and progressed until the third month in 12 eyes of 6 patients. The lesion was round and symmetrical in both eye s, smaller than 2.0 mm, and located during the mean 40.66 +/- 2.46 month fo llow-up, the lesion did not change in size or density. Mean spherical equiv alent refraction after retreatment was 2.88 +/- 0.88 D (range +1.50 to +4.0 0 D) at 1 month and +4.36 +/- 1.83 D at last follow-up. Refraction was unme asurable in 3 eyes. Five eyes lost 1 line of best spectacle-corrected visua l acuity and 7 eyes, 2 or more lines. The surface regularity indexes were h igher than 2.00 in all the eyes. Conclusion: Hyperopic PRK retreatment may cause the sight-threatening compl ication of apical nodular subepithelial corneal scar. This complication beh aves unlike corneal haze and does not resolve spontaneously over time. J Ca taract Refract Surg 2000; 26:352-357 (C) 2000 ASCRS and ESCRS.