In contrast to primary open angle glaucoma, preventive interventions in primary angle closure disease (PACD) can sometimes be definitive. Data from randomized, controlled trials – and where this is not available – principles grounded in known biology, biological plausibility, logic, preferred practice and personal experience have been synthesized to develop explicit clinical algorithms for management of the spectrum of PACD. The mainstay of first-line intervention is usually a laser iridotomy: a commonly necessary but sometimes insufficient manoeuvre in PACD. The crucial stepwise considerations after iridotomy are: whether the angle is open or closed; whether the IOP can be medically controlled; the extent of PAS, and the presence of visually significant cataract. Indication for subsequent interventions – which may include iridoplasty, cataract surgery, trabeculectomy or phacotrabeulectomy – are herein based on an arbitrary threshold (180 degrees) for angle opening and extent of PAS following initial treatment.