Ultrasound Biomicroscopy Findings After Implantation of Gold Glaucoma Shunts for Glaucoma

Abstract

Purpose: : To evaluate the suprachoroidal space after Gold Glaucoma Shunt (GGS) implantation in patients with uncontrolled POAG.

Methods: : Prospective observational study. Inclusion criteria: Patients with POAG who were candidates for glaucoma aqueous shunt surgery after failed surgical glaucoma interventions. 14 eyes of 14 consecutive patients were included and underwent GGS implantation The Gold-Glaucoma-Shunt (SOLX-Corp) is a fine gold valveless flat drainage device (6mm long, 3mm wide. Interior channels diameter: 50 µm) designed to communicate between the anterior chamber and the supraciliary space allowing the aqueous to reach the suprachoroidal space. UBM exams (UBM 840; Zeiss-Humphrey) were performed preoperatively and 1 and 6 months postop. Hourly scans of the angle and the pars plana were taken, radial and transversal scans of the area where the GGS was implanted were also performed. We evaluated the presence of suprachoroidal fluid (hypoechogenic space between the choroid and sclera) and peri-GGS fluid (hypoechogenic space between the GGS and the surrounding tissue). Study visits included measurements of IOP, however the UBM examiner has blinded to the IOP. Non parametric test were used to compare continuous variables, the Chi-square test was used to compare categorical variables.

Results: : Preoperatively UBM did not detect fluid in the suprachoroidal space in any eye. Baseline IOP: 21.7 SD 4.02. Mean number of topical drugs: 2.64 SD 0.6 (Systemic acetazolamide: 3/14 eyes). Mean IOP at one month (all patients untreated): 18 SD 5.5. Mean IOP at six months:19.07 SD 3.6. Mean number of drugs: 0.9 SD 0.9. UBM detected fluid in the suprachoroidal space in 71.4% of the patients at one month and 42.86% at six months. 100% had fluid around the GGS at one month and 64.28% at six months. The peri-GGS fluid could be seen as a slit-like hypoechogenic space around the GGS or/and as a intrascleral lake in the scleral incision area above the GGS. IOP was significantly lower in the patients with fluid in the suprachoridal space.

Conclusions: : UBM allowed us to detect peri-GGS and suprachoroidal fluid after GGS implantation. Long-term longitudinal studies are needed to confirm these findings and analyse the changes over time.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • clinical (human) or epidemiologic studies: systems/equipment/techniques • intraocular pressure