Laser-Assisted Opening of Gold Micro Shunt’s Windows in Glaucoma: Efficacy and Safety

Abstract

Objective: To determine the intraocular pressure-lowering effect and safety of opening the Gold Micro Shunt Plus’ (GMS+) windows with a titanium-sapphire laser. Design: Retrospective case series. Participants: The charts of 5 patients were reviewed. Diagnoses included primary open-angle glaucoma (n=3), aphakic glaucoma (n=1) and neovascular glaucoma (n=1). There were 4 males and 1 female, aged between 56 and 81 (mean age 70±11). They had undergone a mean of 2±1.6 surgeries (range: 0-4) before GMS implantation. Methods: IOP and number of glaucoma medications were recorded before and after the implantation of the GMS in 5 patients, as well as before and after the opening of the GMS’ windows with a titanium-sapphire (Ti-Sap) laser. Patients were assessed for complications arising from implanting the GMS and opening its windows. Follow-up lasted 17 to 42 months. Results: The GMS+ had 8 closed windows and one open flow port upon implantation. Four of these windows were opened in all five patients. Mean IOP before GMS implantation was 29.9±8.5 mmHg and it was 18.6±6.5 mmHg after implantation. Hence, implantation of the GMS was associated with an average decrease in IOP of 11.3±4.2 mmHg or 37.0% (p=0.076). The mean IOP before window-opening was 24.9±5.8 mmHg and after window opening, it was 17.6±5.7 mmHg. The IOP thus dropped 7.3±4.6 mmHg or 29.3% (p=0.055) on average after opening the GMS’ windows. The windows were opened an average 6.4±4.5 months after GMS implantation. IOP at follow-ups remained lower than pre-GMS levels in all patients. The IOP reduction post window opening lasted throughout follow-up, i.e. from 17 to 42 months (average 30±10 months). The number of glaucoma drops for each patient did not decrease after opening the GMS’ windows. One patient developed transitory cystoid macular edema after GMS implantation that resolved with a course of NSAID drops. No complications arose from the opening of the GMS’ windows. Conclusions: In our small case series, opening the GMS’ windows was safe and was associated with a substantial and sustained reduction in IOP.