Manjool Shah, MD, and Steven R. Sarkisian Jr., MD, walk through the complications they faced after the implantation of the XEN Gel Stent (Allergan). Drs. Shah and Sarkisian discuss in detail the different risks presented in ab interno and ab externo cases—such as leaks, erosions, occlusions or obstructions—approaches to avoid these risks, and how to develop your surgical skills following complications.