OBJECTIVE To evaluate the effect of noncontact transscleral Nd:YAG cyclophotocoagulation for refractory glaucoma after penetrating keratoplasty on intraocular pressure, visual acuity, and graft status. METHODS We reviewed the records of all patients treated at the Duke University Eye Center between 1988 and 1993 who had noncontact transscleral Nd:YAG cyclophotocoagulation for uncontrolled glaucoma associated with penetrating keratoplasty. RESULTS One eye each of 39 patients was included in the study. At final follow-up, ranging from three to 63 months (mean, 27 +/- 18 months), the average decrease in intraocular pressure was 15 mm Hg (P = .001). Thirty-one patients (77%) had a final intraocular pressure between 7 and 21 mm Hg. The number of medications was reduced by an average of 1.4 (P = .0001). Five patients (13%) showed an improvement in best-corrected visual acuity at final follow-up; 12 (31%) maintained stable acuity, and 22 (56%) demonstrated a- deterioration in acuity. Of 25 patients with clear grafts before cyclophotocoagulation, 11 (44%) had graft decompensation. CONCLUSIONS Noncontact transscleral Nd:YAG cyclophotocoagulation is effective in lowering intraocular pressure in eyes with refractory glaucoma and associated penetrating keratoplasty, although loss of visual acuity and graft decompensation remain important concerns. Further study is needed of other cyclophotocoagulation protocols and alternative treatments for this patient population.