Nd:YAG Laser for Ahmed Tube Shunt Blockage in Patients Implanted with Boston Type I Keratoprosthesis.

INTRODUCTION: The purpose of this study was to describe the results using the Nd:YAG laser to reopen blocked glaucoma tube shunts in three ocular chemical burn patients with Boston keratoprostesis type I (KPro) implantation.

METHODS: The medical records of the three patients at Zhongshan Ophthalmic Centre were reviewed.

RESULTS: Patient 1, who had glaucoma secondary to KPro implantation, had undergone Ahmed glaucoma valve (AGV) implantation to control an elevated intraocular pressure (IOP). One day after surgery, the tube was observed to be embedded in the residual lens capsule. The capsule was opened by one 1.5 mJ laser pulse, with a subsequent drop in the IOP. In patient 2, the AGV and KPro had been implanted simultaneously. One month after surgery, the IOP increased to 35 mmHg, estimated by palpation, and a vitreous gel was seen blocking the tube. A Nd:YAG laser pulse was used to open the occluded tube. In patient 3, the tube was blocked by iris tissue; Nd:YAG laser treatment opened the tube.

CONCLUSIONS: The cases described here indicate that Nd:YAG laser treatment seems to be a valuable option for opening an occluded AGV tube in patients with KPro implantation. The correct location of the tube tip, visualized through the KPro optic, is essential for laser treatment.