PreserFlo® Microshunt post Pars Plana Vitrectomy: a case report

PURPOSE: Refractory secondary glaucoma following pars plana vitrectomy with heavy silicone oil (Densiron) tamponade represents a significant surgical challenge due to gravity-dependent oil accumulation in the inferior angle. The PreserFlo® MicroShunt is a minimally invasive subconjunctival drainage device composed of highly biocompatible poly-styrene-block-isobutylene-block-styrene (SIBS), featuring a 70 µm lumen designed to regulate aqueous humor outflow with reduced surgical trauma compared to traditional drainage valves. METHODS: We report the case of an 80-year-old male with refractory ocular hypertension peaking at 36 mmHg in the left eye following vitrectomy for retinal detachment managed with Densiron, where gonioscopy confirmed significant oil microemulsions predominantly saturating the inferior angle. Surgical intervention was performed via an ab externo approach with superonasal implantation of the MicroShunt and intraoperative application of mitomycin C. RESULTS: At the six-month follow-up, the intraocular pressure stabilized at 18 mmHg with a functional filtering bleb and stable visual field parameters. CONCLUSION: This case underscores the strategic importance of superior quadrant placement in eyes with heavy oil tamponade, which establishes a drainage pathway physically distant from the primary site of oil accumulation to prevent potential obstruction of the 70 µm device lumen. Our findings support the PreserFlo® MicroShunt as a viable, less invasive alternative for achieving stable intraocular pressure control in complex vitrectomized eyes.