Long-term outcomes of the PAUL Glaucoma Implant Versus Ahmed Glaucoma Valve

Background/aims To compare long-term outcomes of the Ahmed Glaucoma Valve (AGV) and PAUL Glaucoma Implant (PGI) over a minimum of 3 years. Methods This retrospective comparative study included 146 eyes (82 AGV, 64 PGI) who underwent PGI surgery at the University Hospital Bonn and AGV surgery at the University Hospital LMU Munich, Germany. Surgical success was defined according to four intraocular pressure (IOP) thresholds (≤21, ≤18, ≤15, ≤12 mm Hg). Results PGI achieved significantly higher complete success across all IOP thresholds (IOP ≤18 mm Hg: 42.9% vs 26.8%, p=0.043; IOP ≤12 mm Hg: 27.0% vs 7.3%, p=0.001). Qualified success differed significantly only at the strictest threshold (IOP≤12 mm Hg: 42.9% vs 18.3%, p=0.001). PGI showed consistently lower mean IOP from 10 days to 48 months; at 48 months, IOP was 11.0±4.35 mm Hg versus 13.08±3.75 mm Hg in AGV (p=0.010). PGI eyes required fewer medications from 6 months onwards (12 months: 0.40±0.86 vs 1.16±1.17, p<0.001). Secondary glaucoma surgery was numerically less frequent with PGI (9.4% vs 15.9%), although the difference was not statistically significant (p=0.128). Complication rates were similar (p=0.73), although tube erosions occurred more frequently in PGI eyes (10.9% vs 2.4%). Multivariable analysis confirmed independently lower postoperative IOP with PGI (β = –2.78, p=0.001) and higher success probabilities across multiple criteria. Conclusions Both devices provided durable long-term IOP reduction, but PGI demonstrated lower IOP, higher medication-independent success and fewer secondary glaucoma surgeries.