Clinical Outcomes And Associated Complications Of Trans-Scleral Diode Laser Cyclophotocoagulation In Intractable Glaucoma – 10 Years Retrospective Study

To evaluate the long-term effectiveness and safety of trans-scleral diode cyclophotocoagulation (CPC) in treating intractable glaucoma in a tertiary referral centre. We assessed intraocular pressure (IOP) reduction, retreatment rates, medication dependency, and long-term stability over an extended follow-up period. Given the high proportion of neovascular glaucoma (NVG) cases, we also explored whether patient demographics, particularly age and ethnicity, influenced treatment outcomes and the likelihood of requiring retreatment.

A retrospective study conducted at King’s College Hospital NHS Foundation Trust, London, analysing 465 eyes from 420 patients who underwent CPC for advanced glaucoma refractory to conventional treatments between 2013 and 2023.

Success was defined as >20% IOP reduction with the same/fewer medications and IOP from 6–18 mmHg at last follow-up. Failure was not meeting either success criterion at two consecutive visits or requiring further CPC or glaucoma surgery. Intractable glaucoma was defined as unresponsive to maximum medication or prior surgery. The study included POAG (30%), NVG (45.68%), and secondary glaucoma (24.32%). Hypotony was IOP ≤5 mmHg.

Mean follow-up was 32.4 months [0.2–120]. Kaplan-Meier survival analysis modelled long-term success, and logistic regression assessed failure predictors (age, ethnicity, prior treatments). Statistical methods included paired t-tests for IOP reduction, Mann–Whitney, and Kruskal–Wallis tests for distribution differences.

Mean baseline IOP was 35.8 mmHg (95% CI: 34.4–37.1) and 15.4 mmHg (95% CI: 12.6–18.2) at last visit (P < 0.001). Mean energy per eye was 116.9 J. Success achieved in 30.1% of eyes. 69.9% failed. Retreatment/ further surgery was required in 6.9% and 8.2% of cases. Of 465 eyes, 75.3% had 1 CPC (24.3% success). Repeat CPC cases had 5.8% success. Retreated patients were younger (63.6 vs. 68.3 yrs, P < 0.05) and more often Afro-Caribbean (16.1%). Success rates after further CPC were 23.9% (2 CPC), 21.9% (3 CPC), and 16.7% (4 CPC). Medication reduced from 4.4 to 2.6 (P < 0.001). Mean VA reduced from 1.6 to 2.5 logMAR. 1.5% of patients lost light perception. Complications included hypotony (6.3%), macular oedema (0.22%) and uveitis (3.01%).

CPC is an effective intervention for intractable glaucoma, achieving clinically significant IOP reduction over a 10-year period. The success rate at the last available follow-up was 30.11%, highlighting CPC’s role in reducing IOP while maintaining pharmacologic control. Kaplan-Meier analysis confirmed the long-term

stability of IOP reduction. Patients with NVG or Afro-Caribbean ethnicity were more likely to require additional procedures, while younger age was a significant predictor of retreatment. Medication burden significantly reduced post-treatment, reflecting the efficacy of CPC. These findings emphasize the need for individualised treatment strategies, particularly in high-risk ethnic and diagnostic subgroups.