Factors responsible for retinal attachment include structural factors such as the integrity of the retina and the interdigitation of receptor cells with the retinal pigment epithelium combined with dynamic factors which include the movement of water from the vitreous to the choroid under the influence of colloid osmotic pressure in the presence of an intact posterior blood-ocular barrier. In successful retinal detachment surgery an intact cortical vitreous is important. Retinal detachments can be subdivided into simple or complex according to the degree of vitreous abnormality present. Complex detachments demand vitreous surgery and the use of vitreous substitutes. Silicone oil may have a dual role in the eye, tamponade of retinal breaks and waterproofing of the retina with which it is in contact, so reducing transretinal water movement and lightening the load on the mechanisms responsible for retinal reattachment.