Vitrectomy surgery also has a role in retinal detachment repair. This technique removes the vitreous gel and any scar tissue from the eye. After the retina reattachment, a gas bubble fills the vitreous cavity to help hold the retina in position. The bubble generally lasts in the eye for several weeks and is gradually absorbed by the body. A silicone oil bubble is an alternative to an oil bubble in more complex cases. Once the retinal tissues are stable, a second surgery removes the silicone oil because it does not dissolve on its own.