This is the removal of the vitreous jelly with a special cutter (vitrector). It is often done in cases of vitreous haemorrhage or retinal detachment.
In patients with diabetes, a vitrectomy is often coupled with endolaser of the ischaemic retina, in the hope of reversing or preventing neovascularisation.
In the treatment of retinal detachment, vitrectomy is accompanied by cryotherapy (freeze/thaw cycles) to seal the retinal breaks and allow flattening of the detached retina. Expansile gas is often left inside the eye to help push the retina flat. The gas is reabsorbed over several weeks. Initially, the patient cannot see through the gas, but vision returns once the gas disappears and the eye fills with clear transudate.
The vitrectomy procedure itself may cause a retinal detachment.