Secondary Angle Closure Glaucoma

Secondary angle closure glaucoma is a very heterogeneous subtype of glaucoma with a variety of possible causes leading to a blockade of the regular aqueous humour flow or outflow. A distinction is made between secondary pupillary block, angle closure with "pulling" or angle closure with "pushing" mechanisms. For each of these three subgroups, there are different causes, which in turn require individual therapy. Treatment of the underlying cause should always take priority whenever possible. Reduction of the intraocular pressure is often a symptomatic therapy with surgical, pressure lowering procedures showing a limited success rate in many forms of secondary angle closure glaucoma. This article intends to provide an overview of the different causes of secondary angle closure, diagnostic approaches and targeted therapies of exemplary causes of each subgroup.From the group of secondary pupillary block, mechanical causes, iris bombe, and intraoperative air or oil input are addressed, from the group of "pulling" causes, angle neovascularization, post-inflammatory angle changes, and iridocorneal endothelial syndrome and for the group of "pushing" mechanisms, gas endotamponade, retroiridal neoplasms and aqueous misdirection syndrome.While secondary angle closure is one of the most challenging glaucoma subgroups for treatment it is crucial to know the different subgroups and their development to choose the right treatment.