Abstract
PURPOSE: The Paul Glaucoma Implant (PGI) is a novel non-valved glaucoma drainage device designed to lower intraocular pressure (IOP) in patients with refractory glaucoma. This systematic review aims to evaluate the current evidence on safety, efficacy, and emerging applications of PGI implantation. METHODS: A systematic literature search was conducted following PRISMA guidelines across PubMed/Medline, Embase, Cochrane, Google Scholar, and Web of Science databases up to April 2025. Quality assessment was performed using the NIH Quality Assessment Tool for Before-After Studies. Data on patient demographics, surgical techniques, IOP outcomes, success rates, and complications were extracted and analyzed. RESULTS: Eighteen studies (946 eyes) met the inclusion criteria. The PGI consistently demonstrated significant IOP reduction across various studies and glaucoma subtypes. Mean IOP reductions ranged from 14.8 mmHg to 19.1 mmHg, depending on follow-up duration and patient characteristics. Complete success rates ranged from 38.4% to 75%, while qualified success rates were consistently high, reaching up to 93.2%. The PGI's unique design, featuring a smaller inner tube diameter (0.127 mm), is thought to contribute to a lower risk of hypotony compared to other non-valved implants. Three comparative studies with other GDDs reported similar success rates with potentially fewer early complications. Quality assessment revealed moderate-to-good quality evidence, with limitations including short follow-up periods and predominance of uncontrolled studies. CONCLUSIONS: The PGI is emerging as a safe and effective surgical option for treating refractory glaucoma. Its smaller tube diameter and large surface area endplate contribute to efficient IOP control with a potentially lower risk of hypotony.