Efficacy and Safety of Diode Laser Transscleral Cyclophotocoagulation in Patients with Glaucoma

Purpose: To evaluate the efficacy and safety of transscleral diode cyclophotocoagulation (TSCPC) at 2 years of follow up. Methods: This is a retrospective review of the records of all adult patients who underwent their first TSCPC treatment between 2014 and 2019 at Unidade Local de Sa & uacute;de de S & atilde;o Jo & atilde;o, Porto, Portugal. Data regarding intraocular pressure (IOP), best corrected visual acuity, number of IOP-lowering medications, use of oral acetazolamide, retreatments and complications during a 2-year period following TSCPC were registered. The primary outcome was overall success at 2 years, defined as IOP >= 6 and <= 21 mmHg, with at least 20% IOP reduction from baseline, with or without IOP-lowering medications (qualified and complete success, respectively), without the development of phthisis bulbi or loss of light perception due to glaucoma and no further glaucoma procedures except TSCPC retreatment. Results: Ninety-six eyes from 96 patients were included, mean age was 63 (+/- 14) years. Mean IOP at baseline was 39.1 (+/- 13.3) mmHg. Mean IOP reduction at 2 years was 18.5 (42.9%) mmHg (+/- 16.0, min -16.0, max 56.0) (p < 0.001) and a significant reduction in the number of IOP-lowering medications and use of oral acetazolamide was observed. IOP reduction at 2 years was positively correlated with baseline IOP (r=0.682; p < 0.001). Overall success (including complete and qualified) was achieved in 42 patients (43.8%), with 34 (35.4%) presenting qualified success. Neovascular glaucoma (NVG) was the predominant diagnosis (n = 30, 31.3%), with a higher mean baseline IOP of 46.3 mmHg (+/- 11.8, min 21.0, max 70.0) and a larger mean IOP reduction at 2 years of 24.7 (51.0%) mmHg (+/- 16.4, min -2.0, max 55.0). Thirteen patients (13.5%) developed persistent hypotony, eight of which converted to phthisis bulbi, of which half had NVG. Conclusion: TSCPC can be an effective IOP-lowering procedure, demonstrating a stronger effect when the preoperative IOP is highest. However, there is a wide variability in the effect (specially in eyes with NVG) and some relevant complications, including 8.3% of patients developing phthisis bulbi after 2 years of follow up.