A vitrectomy is a vitreoretinal surgery that removes the jelly-like substance inside the eye called vitreous. This is done in the operating room underneath a surgical microscope while the patient is generally under local anesthesia. Small incisions are made in the eye wall, allowing the vitreous to be removed using small instruments. The incisions allow entry of fiber-optic lights to see inside the eye, and often to deliver laser treatment if necessary.
At the time of a vitrectomy, the eye is often filled with air, or a mixture of air and gas. This may be done to prevent or repair a retinal detachment, macular hole, macular pucker, or for other reasons. The gas is reabsorbed by the eye over a period of time; air typically lasts around one week, while longer acting gases may take 2 months to be reabsorbed. It is gradually replaced with the clear aqueous fluid that naturally produced by the eye.