A vitrectomy is a surgical procedure to remove the vitreous humour inside the eye. A vitrectomy may be required if there is a bleed in the jelly or after complications in cataract surgery or in certain conditions affecting the retina. Once the jelly is removed, any retinal surgery will be performed. The eye is then filled with saline or temporary silicone oil. A gas bubble may also be inserted to help flatten the retina. If oil or gas is used, you will be advised to position your head in a particular way. This should be maintained for around 1 to 3 weeks as instructed by your Doctor.