Ahmed glaucoma valve implantation, as the main treatment option for refractory glaucoma, can control intraocular pressure (IOP) to a large extent. And its efficacy and prognosis are superior to those of conventional filtration surgery. IOP is well-controlled in the early postoperative stages. However, long-term fibrosis of encapsulated bleb inhibits fluid exchange and causes elevated IOP, leading to surgical failure. Therefore, treating fibrosis of encapsulated bleb can improve the long-term success rate after glaucoma valve implantation, which is also a research hotspot. Currently, the main clinical interventions are preoperative prophylaxis and postoperative secondary operations for fiber wrapping, but its long-term efficacy is not satisfactory. This article reviews the occurrence, histopathology and molecular mechanism of fibrous encapsulation, treatment in a clinical setting, cutting-edge research progress, and exploration on material modification of Ahmed glaucoma valve.