Case. A flat anterior chamber is observed on postoperative day (POD) 1 (A). On POD 121, a well-formed filtration bleb is seen (B); synechial formation to the shunt obstructs the axial port (C, arrow) but not the relief port (C, arrowhead). On POD 274, synechiae obstruct both the axial (D, arrow) and relief ports (D, arrowhead). The obstruction opens after neodymium:yttrium-aluminium-garnet laser therapy (E, arrow and arrowhead), leaving synechiae around the shunt (E, red arrowhead). The cystic bleb is reformed and maintained up to POD 333 (F).