Long-term limitations and complications of trans-scleral diode laser cycloablation for refractory glaucoma

Background Trans-scleral diode laser cycloablation (cyclodiode) is effective in the short-term management of refractory glaucoma where alternative treatments are not feasible. Long-term outcomes of 5-years or more are not well-documented, particularly in relation to intraocular pressure (IOP) control, need for further procedures and complications such as hypotony and phthisis. Methods A review was undertaken of patient medical records with refractory glaucoma who underwent cyclodiode at City Eye Centre in Brisbane from 2012 to 2016. Data included sex, age, laterality, type of glaucoma, cyclodiode parameters, number of glaucoma medications, visual acuity and treatment with acetazolamide. Data were analysed using generalised linear modelling and Kaplan-Meier analysis. Results A total of 54 eyes in 54 patients (29 M:25F) with a mean age of 66 years (range 15-85 years) with a minimum of 5 years follow up were included. The mean number of burns was 23.3 (range 12-40) over 180-270 degrees, mean power per burn was 1967 mW (range 1500-2000 mW), with a mean duration of 1981 ms (1500-2000 ms). The mean pre-treatment IOP was 31.5 mmHg (range 17-56 mmHg) and mean IOP 5 years post-treatment was 16.1 mmHg (2-42 mmHg). The mean number of pre-treatment medications was 3.6 (range 1-6) and 2.7 (range 0-5) 5 years post treatment, including 5 (8.3%) on oral acetazolamide. Complications of cyclodiode were seen in 6 (11.1%) patients, including 3 (5.0%) cases of hypotony, and 2 (3.3%) phthisis. Conclusion Cyclodiode is often utilised for end-stage glaucoma when the IOP is uncontrolled on medical treatment and drainage surgery is not indicated, resulting in long-term reduction of IOP and the number of medications, including acetazolamide. Hypotony and phthisis can be significant complications.