What is a Pars Plana Vitrectomy?
Inside the main body of the eye, behind the iris and in front of the retina, is the vitreous gel. It is composed of collagen fibers and other molecules suspended in water to form a clear gel that is adherent to the retina. Abnormalities of the interface between the retina and vitreous cause of many different retinal pathologies that require the removal of the vitreous with a procedure called vitrectomy. To access the posterior segment of the eye and remove the vitreous, small incisions must be made in the wall of the eye. These incisions are positioned in the space behind the iris and in front of the retina in the area of the Pars Plana; this is why the surgery is termed Pars Plana Vitrectomy (PPV).
How is a Pars Plana Vitrectomy performed?
Since the vitreous is a gel with a structure and not just a liquid, the vitreous must be cut and not just aspirated or sucked out to minimize damage to the retina; this cutting is the key to vitrectomy surgery. Beginning in the 1970’s, machines were created to cut the vitreous gel and remove it. Technological advances have improved the surgical techniques and equipment, allowing for smaller incisions and faster vitreous cutting. Now, modern vitrectomy machines allow 23 or 25 gauge instruments using incisions as small as 0.5mm and cutting as fast as 5,000 cuts/minute to 7,500 cuts/minute.
Surgery is performed in the operating room under sterile conditions
The surgery is performed in the operating room under sterile conditions. The procedure starts with using a large microscope to look through the pupil with special focusing lenses that provide a detailed and magnified view. Three incisions are made and through one a fluid infusion is placed, the second a light to provide illumination, and the third a vitreous cutter or other surgical instrument. Carefully, the vitreous is removed from the center of the eye and the posterior vitreous is separated from the retina. The base of the vitreous is closely shaved to remove all vitreous gel possible. As the gel is being removed, the volume in the eye is replaced with a specially prepared, nutrient rich, pH balanced solution. Depending on the surgery, the eye may remain filled with this solution and it will be slowly absorbed and replaced with the eye’s natural fluid. Other surgeries may require all fluid in the eye be removed and a special gas bubble placed to support the retina.
What are the risks with Pars Plana Vitrectomy?
The greatest risk with any incisional surgery is the risk of infection, in the eye this is known as endophthalmitis. Endophthalmitis is a very serious condition that can lead to severe ocular damage and blindness. Great care is taken when performing eye surgery to minimize this risk and is why these procedures are performed under sterile conditions in the operating room. The eye is cleaned with betadine to kill surface bacteria and antibiotics are used both during surgery and after surgery. New surgical techniques with small incisions have greatly decreased the risk of infection.
Additional risks with surgery include tissue damage that may result in retinal detachment, scarring of the retina, elevated eye pressure (glaucoma). While all possible measures are taken to reduce these risks as much as possible they can never be zero. It is very important to weigh the risks with the benefits from the surgery when making the decision for surgery.
As a consequence of removing the vitreous, cataract formation is accelerated. While all people will develop a cataract as a normal process of aging, having vitrectomy surgery makes the cloudiness to the eye’s lens happen quicker. Cataracts are a treatable condition but do require a surgery to remove the lens and replace it with a clear lens implant.
Why do I need to be face down after surgery?
Depending on the type of surgery, the eye may be filled with gas or silicone oil to hold the retina in place while healing. To keep these vitreous substitutes holding the retina, the eye needs to be position facing down allowing the gas or oil to float up to maintain contact with the retina. Different procedures require different lengths of time in the face down position. Intraocular gas will resorb and be replaced by the eye’s natural fluid. Special formulations are prepared that will resorb at different rates, giving support for differing periods of time. Silicone oil does not resorb and will maintain its support until it is removed.
What is the recovery time? When can I go back to work?
Pars plana vitrectomy is a major surgery for the eye and care must be taken during recovery to provide a good environment for the eye and retina to heal. It is important to avoid any water in the eye for the first week after surgery to allow the incisions to heal and limited physical activity is necessary for 1 month after surgery to give the incisions in the eye time to strengthen. The most important factor is the presence of gas or oil to support the retina and time away from work should be taken as long as is necessary to maintain positioning. Additionally, while gas is in the eye the vision will be very blurred as light cannot pass through the gas which will make working difficult and driving dangerous.