Endoscope guided glaucoma surgery
Introduction: The basic principles of glaucoma surgery are 1) reduction of aqueous humor formation in the ciliary body or 2) improvement of aqueous humor outflow through the trabecular meshwork. Both anatomic sites, ciliary body and trabecular meshwork, can be directly visualized using an endoscope system.
Method: A reduction of aqueous humor formation can be achieved by endoscopic cyclophotocoagulation. An improvement of aqueous humor outflow can be obtained by endoscopic laser goniotomy. Endoscopic cyclophotocoagulation is performed with a thermal diode laser. The total diameter of the probe carrying the endoscope and the laser fibre is about 1 mm. Usually a pars plana approach is recommended, sometimes, an approach via the anterior chamber is used. Endoscopic laser goniotomy is performed with a photoablative Erbium:YAG laser, normally via a small corneal incision.
Results: Endoscopic cyclophotocoagulation allows a very precise localising and dosing of the laser beam. Our own experience with this procedure, as well as the data given in the literature, show that it leads to a marked intraocular pressure reduction even in "worst cases". Endoscopic laser goniotomy stands out for very rare complications and the potential of treating difficult cases (i. e. pemphigoid, opaque corneae). It also leads to a marked intraocular pressure reduction.
Conclusions: Endoscopic cyclophotocoagulation as well as endoscopic laser goniotomy represent a new class of glaucoma surgery. Long term results are still missing. The intermediate results now available (1 - 2 years follow-up) are encouraging.
University eye hospital, Killianstr. 5, D-79106 Freiburg