Single versus Double Preserflo MicroShunt Implantation in Glaucoma Patients: A Retrospective Cohort Study

Introduction The aim of this study is to describe and evaluate double Preserflo MicroShunt implantation as a modified micro-invasive glaucoma surgery technique and to retrospectively compare the outcomes in a cohort of glaucoma patients with single or double implantation.Materials and Methods A retrospective data analysis of 57 glaucoma patients who consecutively underwent Preserflo implantation was performed. Medical records were examined for patients' demographics, glaucoma type, intraocular pressure (IOP), medication, complications and re-interventions. Two groups with single (n=29) or double (n=28) implantation were formed and the outcomes were compared. In cases of two-stage double implantation (n=17), the course of the initial and the second implantation were compared.ResultsMean preoperative IOP was significantly higher in the double compared to the single implantation group (29.4 +/- 10.0mmHg; 21.7 +/- 8.2mmHg; P=0.003). Postoperatively, IOP was significantly lower in the double implantation group at various time-points (day 1, week 1, months 3 and 6; all P<0.021). In the subgroup with two-stage procedures, mean preoperative IOP was 24.5 +/- 8.5mmHg and 29.8 +/- 10.1mmHg, respectively; P=0.128). While immediately postoperatively, mean IOP-lowering was clinically significant and similar following both procedures, thelonger sustainable effect was observed after the second procedure (month 12: 25.5 +/- 7.5mmHg; 12.4 +/- 4.8mmHg; P=0.001). No serious complications were observedDiscussion/Conclusion Double Preserflo implantation appears safe and efficient for lowering IOP in glaucoma patients. Our preliminary findings suggest that double is superior to single implantation in terms of IOP-lowering and the need for additional topical medication. Patients with insufficient IOP-lowering following single implantation may benefit from a second implantation. Further research is warranted to evaluate double implantation as a first-line, one-stage procedure.