Abstract
Purpose:
To evaluate the suprachoroidal space after CyPass (CP) implantation in patients with uncontrolled POAG.
Methods:
Prospective observational study. Inclusion criteria: Patients with POAG who were candidates for glaucoma surgery (uncontrolled IOP on medical therapy). 24 eyes of 24 consecutive patients were included and underwent ab interno CP implantation. The CP (Transcend medical, CA) is a 6.25 mm long tube with a through lumen (outer diameter: 0.51 mm) 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 at 2 and 6 months and one year postop. Hourly scans of the angle and the pars plana were taken, radial and transversal scans of the area where the CP was implanted were also performed. We evaluated the presence of suprachoroidal fluid (hypoechogenic space between the choroid and sclera) and peri-CP fluid (hypoechogenic space between the CP and the surrounding tissue) with radial scans and the pars plana indentation by the CP (transversal scan). 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:
Baseline IOP: 20.9 SD 5.7. Mean number of topical drugs: 2.33 SD 0.7. Mean IOP at one month (all patients untreated): 15.4 SD 4.2. Mean IOP at six months: 14.95 SD 3.3. Mean number of drugs: 0.7 SD 0.9.Mean IOP at one year: 17,6 SD 3.4. Mean number of drugs: 1.1 SD 1.0. UBM detected fluid in the suprachoroidal space in 100% of the patients at two months (5 in four quadrants and all the other in the quadrant where the CP was implanted). At six months 54% (5 in four quadrants, 8 in one) and 33% at one year (only one patient had liquid in four quadrants). 100% had fluid around the CP at two months and 91,6% at six months. At one year only 13% had peri-CP fluid. Pars plana indentation was found in 6 patients in all exams. However transversal scans of the distal end of the CP could not be obtained in 3 patients.
Conclusions:
UBM allowed us to detect peri-CP and suprachoroidal fluid short- term after CP implantation. The displacement of the dispositive or the scarring of the suprachoroidal space may be reasons for explaining lower effect of Cypass over time in some patients.
Keywords: 568 intraocular pressure •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
465 clinical (human) or epidemiologic studies: systems/equipment/techniques