A comparison of two energy levels for noncontact transscleral neodymium-YAG cyclophotocoagulation.

In a prospective, clinical trial, 89 patients undergoing transscleral neodymium-YAG cyclophotocoagulation for intractable glaucoma were randomized to approximately 4 or 8 J of laser energy per application and followed up for an average of 1 year. The only statistically significant difference between the two groups was early anterior chamber reaction, which was more severe among those receiving 8 J. There was a trend toward better intraocular pressure control in the 8-J group, compared with the 4-J group, with 33 (75%) of 44 patients and 27 (60%) of 45 patients, respectively, requiring no further surgical intervention during the follow-up period. Among those patients not requiring further surgery, there was no significant difference in final visual acuities between the two groups. These findings suggest that within the range of 4 to 8 J, transscleral neodymium-YAG cyclophotocoagulation at the higher energy level may have some advantage with regard to intraocular pressure reduction without an increased risk of visual loss, compared with the same treatment at the lower energy level.