Audible pops during cyclodiode procedures.

PURPOSE: This study was conducted to determine the incidence of intraocular uveal microexplosions ("pops") during contact diode laser transscleral cyclophotocoagulation (cyclodiode) and to analyze the influence of pop occurrence on results and postoperative complications.

METHODS: Cyclodiode treatment (1.5-2 W x 2 seconds over 270 degrees) was performed in 43 consecutive patients (43 eyes) with uncontrolled glaucoma who had not undergone previous ciliary ablation. Mean duration of follow-up evaluation was 12.7 months (range, 9-18 months). These eyes included 31 seeing eyes, in which intraocular pressure (IOP) reduction was indicated to preserve visual acuity (therapeutic group) and 12 blind eyes, in which IOP reduction was advisable to relieve pain (palliative group). Success was defined as a final IOP > or = 5 mmHg and < or = 21 mmHg in seeing eyes, and as the resolution of pain in blind eyes. Potential factors evaluated for intraoperative pop occurrence included patient age, gender, iris color, glaucoma diagnosis, preoperative IOP, and number of previous surgical procedures used to treat glaucoma.

RESULTS: In the group receiving therapeutic treatment, mean +/- standard deviation (SD) IOP was 41.8 +/- 12.7 mmHg before surgery and 19.2 +/- 8.3 mmHg after surgery; the success rate in this group was 83.9%. In the group receiving palliative treatment, mean IOP was 55.4 +/- 13.7 mmHg before surgery and 21.1 +/- 13.4 mmHg after surgery; success rate was 83.3% in this group. Intraoperative microdisruptions occurred in 48.8% of the cases during the first laser application; 67.5% of these occurred in the superior half of the eye. No significant difference in rate of intraoperative pop was observed between patients after one cyclodiode session and those eyes that underwent additional sessions. Mean baseline IOP was significantly higher in patients with intraoperative occurrence of pops. An audible pop was more common in the group undergoing palliative treatment. Intraoperative occurrence of pops was associated with a greater severity of postoperative iridocyclitis. All patients with postoperative hyphema also had pops during surgery. No significant difference in the success rate was found between patients in whom intraoperative pops did and did not occur.

CONCLUSION: Choroidal vaporization is significantly more common in patients with higher baseline IOP. Occurrence of pops also is associated with more severe postoperative inflammation and with a greater risk of postoperative hyphema.