The vitreous gel may also be removed if blood in the vitreous gel (vitreous hemorrhage) does not clear on its own. After a vitrectomy, the vitreous is replaced as the eye secretes aqueous and nutritive fluids.The vitreous, which makes up approximately two thirds of the eye's volume, is a normally clear, gel-like substance that fills the middle of the eye.It may be done when there is a retinal detachment, since removing the vitreous gel gives your eye doctor (ophthalmologist) better access to the back of the eye.

The procedure may be performed to clear blood and debris from the eye, to remove scar tissue, or to alleviate traction on the retina. Blood, inflammatory cells, debris, and scar tissue obscure light as it passes through the eye to the retina, resulting in blurred vision. The vitreous is also removed if it is pulling or tugging the retina from its normal position.

Procedure:

A special operating microscope and special lenses that provide a clear image of the rear portion of the eye is used for the surgery. Small instruments are inserted into the eye which cuts the vitreous gel, and suctions it out. After removing the vitreous gel, the surgeon may treat the retina with a laser (photocoagulation), cut or remove fibrous or scar tissue from the retina, flatten areas where the retina has become detached or repair tears or holes in the retina or macula. The length of the surgery depends on whether additional procedures are required and the overall health of the eye.

A Fiber optic light source is used to illuminate and visualise the inside the eye during surgery. The surgeon would often use an infusion line to maintain the eye'x shape during surgery.Silicone oil or a gas (perfluropropane) is injected into the eye to replace the vitreous gel and restore normal pressure in the eye towards the end of the surgery.

Vitrectomy is always done by an eye doctor who has special training in treating problems of the retina.

The most common eye conditions that benefit from vitrectomy include:

• Retinal detachment - a blinding condition where the lining of the eye peels loose and floats freely within the interior of the eye.
• Diabetic retinopathy - may damage sight by either a non-proliferative or proliferative retinopathy.
• Macular holes - the normal shrinking of the vitreous with aging can occasionally tear the central retina causing a macular hole with a blind spot blocking sight.
• Vitreous hemorrhage - Bleeding in the eye from injuries, retinal tears, subarachnoidal bleedings (as Terson syndrome),or blocked blood vessels. The following techniques may be used to treat the retina along with Vitrectomy.
• Laser is sometimes used to stop tiny retinal vessels from bleeding inside the eye
• A small gas bubble may be placed inside the eye to help seal a macular hole.
• After reattachment surgery, the eye may be filled with silicone oil to keep the retina in position.

Vitrectomy has been shown to greatly improve visual acuity in many people who have severe vitreous hemorrhage that has not cleared on its own. A vitrectomy can decrease the risk of severe bleeding in people who have begun to have bleeding into the vitreous gel. It can also reduce the risk of severe bleeding in people with growth of abnormal blood vessels in the iris.

Surgery can restore some vision lost as a result of traction retinal detachment and may help prevent further detachment. But the results tend to be better when the detachment has not affected the center of the retina (macula) and the central vision it provides.

A tear or hole of the retina that leads to a peripheral retinal detachment causes the loss peripheral vision. This situation will progress to a full retinal detachment and loss of all vision if the problem is not repaired. The surgical repair of a retinal detachment is usually successful in reattaching the retina. Scleral buckling is the standard treatment for detached retinas. The surgery is done in anoperating room under general or local anesthesia. The surgeon identifies the holes or tears either through the operating microscope. The hole or tear is then sealed, either with diathermy, a cryoprobe, or a laser. This resulting scar tissue formed around the retinal tear keep it permanently sealed, so that fluid no longer can pass through and behind the retina. A scleral buckle, which is made of silicone, plastic, or sponge, is then sewn to the outer wall of the eye (the sclera). The buckle is like a tight cinch or belt around the eye. This application compresses the eye so that the hole or tear in the retina is pushed against the outer scleral wall of the eye, which has been indented by the buckle. The buckle may be left in place permanently. It usually is not visible because the buckle is located half way around the back of the eye and is covered by the conjunctiva.