Diode laser transscleral cyclophotocoagulation for the treatment of refractory glaucoma after penetrating keratoplasty

Purpose: To evaluate the effect and safety of diode laser transscleral cyclophotocoagulation ( TSCPC) in eyes with refractory glaucoma after penetrating keratoplasty (PK). Methods: Diode laser TSCPC was performed on 32 eyes of 32 patients with secondary glaucoma after penetrating keratoplasty. The mean follow-up period was 11.4 +/- 3.8 months (range, 6-20 months). The intraocular pressure (IOP), number of glaucoma medications, graft status, side effects, and complications of the procedure were all recorded during the follow-up period. The treatment was considered successful if after one cyclodiode treatment the IOP could be reduced to or below 22 mmHg with or without medication. The success rate of the diode laser treatment was analyzed by the Kaplan-Meier survival analysis method during the 6th and 12th months of the follow-up period and the end of the study. The decrease in drug requirement after laser treatment was analyzed by the Wilcoxon nonparametric test. Statistical significance was set at p < 0.05. Results: During the follow-up period, diode laser TSCPC reduced the IOP significantly. Our cumulative success rate was 56 % at the end of the study. Cyclodiode treatment resulted in an IOP less than 22 mmHg in 97 % of the eyes on the 6th month and 72 % of the eyes on the 12th month with or without medication. The total retreatment rate of the study was 44 %. More than one treatment was necessary, 8 times in the 1st month, 9 times in the 3rd month, 5 times in the 6th month and 3 times in the 12th month. The average number of antiglaucomatous drugs used was 2.8 before surgery and 1.2 after the 12th month follow-up period (p < 0.05). No eyes with graft failure after treatment were present. Visual acuity improved ( > 2 Snellen lines of acuity) in two eyes and remained the same in the others. No serious side effects such as phthisis bulbi or hypotonia were observed. Conclusions: Diode laser TSCPC appears to be a safe and effective procedure for the treatment of uncontrolled glaucoma secondary to penetrating keratoplasty.