Purpose: To evaluate risk factors associated with hypotony after transscleral diode cyclophotocoagulation (TCP) in East Asian patients with intractable glaucoma.
Methods: Clinical data from 90 eyes of 90 patients who underwent TCP for various indications at Singapore National Eye Centre between 2005 and 2007 were retrospectively reviewed. Baseline intraocular pressure (IOP) was compared with postoperative IOP at 1 month, 3 to 6 months, and 1 year. Mean total energy per session was calculated in Joules and retreatment rates were recorded. Change in visual acuity and number of medications were recorded at 1-year follow-up. Success was defined as percentage of patients achieving an IOP of 5 to 21 mm Hg with or without medications. Hypotony was defined as IOP <5 at the end of 1-year follow-up period. Factors, such as underlying diagnosis, total energy used, age, earlier operations, and retreatment rates, which may influence the development of hypotony were analyzed using univariate analysis.
Results: Success was achieved in 54.0% of patients. Mean total energy used was 83.3±31.7 J. Mean pretreatment IOP was 41.8±12.9 mm Hg, which reduced to 20.7±12.1 mm Hg (P<0.001) at 1 month and 17.8±12.9 mm Hg (P<0.001) at 1 year. Sixteen (39.0%) patients developed hypotony. Univariate analysis showed that neovascular glaucoma patients have a significantly increased risk for developing hypotony post TCP (odds ratio=9.17, 95%; confidence interval=1.85-45.36).
Conclusion: Underlying diagnosis of neovascular glaucoma is a significant risk factor for hypotony post TCP.