Most vitreous and epiretinal membrane operations can be done perfectly comfortably under a local anaesthetic. That is a numbing injections around the eye.

Occasionally, this is supplemented with some sedation, which is given into a vein. In other cases, patients who are not happy about having the operation done, or who would find it difficult to lie flat on their back for a period of an hour, are put to sleep and have the surgery done under a general anaesthetic.