Transscleral cyclophotocoagulation is not usually considered as the first line surgical therapy for glaucoma. However, it still remains an important tool for lowering intraocular pressure in certain patients. It is quick and easy to perform and acts through an alternative physiological approach compared to filtration surgery. As the ciliary body is not directly visible, an empirical distance from the limbus is often used for placement of the laser probe; however, the anatomical structures can be highly variable. Diaphanoscopy provides a very simple and effective way to visualize the ciliary body before or parallel to the cyclophotocoagulation. It helps to direct the laser beam more precisely to the ciliary body and to prevent a false anterior placement of the beams, that carries a great risk of side effects. This article provides an overview on the concept of diaphanoscopy for cyclophotocoagulation.