This is an authoritative review of a controversial and difficult clinical area. The authors have experience of over 350 cases and provide a well-structured review of the classification and management of orbital vascular malformations. They emphasise the need to understand the haemodynamic characteristics of each lesion, which will largely determine not only its clinical behaviour but also the way it is managed. The merits of the different methods available to assess these lesions are described, and the authors stress the importance of dynamic imaging to detect distensible venous lesions, including Valsalva-augmented venous phase CT angiography (a technique described in depth in an accompanying article in the same issue). They then detail the clinical characteristics and imaging findings of the various malformations based on their haemodynamic properties and histology, from high flow arterial lesions to low flow venous and lymphatic malformations, including the mixed and complex variants. Helpful management strategies are provided, with some useful tips gained from their extensive experience, e.g. occasionally some lymphaticovenous malformations may mimic a cavernous haemangioma, but during surgery are found to have an adherent ‘stuck’ tail which would warrant a different, more cautious surgical removal. The limitations of traditional surgical techniques are described, along with newer interventions including intra-lesional sclerotherapy or glueing, either perioperatively with simultaneous excision or via endovascular and percutaneous image-guided approaches.