[Post-surgical treatment after non-penetrating glaucoma surgery: the goniopuncture]

Abstract

Non-penetrating glaucoma surgery was primarily developed as an alternative to the widely applied trabeculectomy. Since the anterior chamber in non-penetrating surgery is not directly opened, common postoperative complications such as hypotony are rare. The most frequently applied technique in this group is the deep sclerectomy. After having prepared a superficial scleral flap a deeper scleral flap is performed and excised unroofing Schlemm's canal. The trabecular meshwork is then peeled leaving a residual trabeculodescemet membrane. As a consequence aqueous humour diffuses via the trabeculodescemet membrane under the scleral flap and subsequently under the conjunctiva. One of the reasons for a postoperatively high IOP is seen in the resistance of the residual trabculodescemet membrane. A solution to this problem lies in its puncture, the so-called goniopuncture. Goniopunctures are done in approximately 50 % of cases after deep sclerectomy and are also applied in cases of canaloplasty and viscocanaloplasty. Usually a 1064 nm Nd : YAG laser is used. A potential risk of iris incarceration is described. Two studies have shown that an equally IOP lowering effect can be achieved by treating the trabeculodescemet membrane with a frequency-doubled 532 nm Nd : YAG laser (SLT). No complications were detected in those cases. In conclusion, goniopuncture should be considered as the first line treatment for postoperative IOP increase in cases of non-penetrating glaucoma surgery. It should therefore be preferred to a (re)start of topical treatment.