Use of neodymium: YAG laser to open an occluded molteno tube

A patient with refractory glaucoma secondary to trauma and repeat penetrating keratoplasty had Molteno implant surgery to control elevated intraocular pressure. Six weeks after surgery intraocular pressure rose abruptly, and a fibrinous membrane was seen covering and occluding the tip of the Molteno tube. The Q-switched neodymium (Nd):YAG laser was used successfully to open the membrane, with subsequent renewal of aqueous flow and control of intraocular pressure. Bevel-up cutting of the tube tip facilitates Nd:YAG laser opening of such an obstruction. We describe this use of the Nd:YAG laser and recommend bevel-up trimming of implant tubes in aqueous implant surgery.