What is a Pars Plana Vitrectomy?

The vitrectomy procedure was pioneered in the late 1960s and early 1970s to remove vitreous from inside of the eye. Over time, the original vitrectomy procedures were streamlined so that more procedures could be incorporated into the surgery and more conditions could be treated. If a patient needs a vitrectomy, it is important to have an understanding of what the procedure entails and what to expect.

Vitreous Description

• The vitreous fluid is the clear jelly that fills the back of the eye and presses against the retina. The vitreous is composed mostly of water; however, the vitreous itself is unable to clear itself of any type of debris that might accumulate in the eye, such as blood or substances from inflammatory processes. If enough of these materials collect in the vitreous, vision can be decreased. During a pars plana vitrectomy--named after the part of the eye the instruments are placed in-- the vitreous is removed, along with any debris.

Pars Plana Definition

• There is a reason for the name of the procedure. The pars plana is the section of the eye between the retina and the pars plicata. The retina is the multi-layer of cells in the back of the eye that sends images to the brain; the pars plicata creates the fluid in the front of the eye (aqueous humor). The pars plana has no specific use and is a safe place to place the vitrectomy instruments where there won't be any damage to any tissues.

Indications

• Some diseases that can be treated with a pars plana vitrectomy are diabetic eye disease, retinal detachments, holes in the retina and vitreous hemorrhage. Diabetic eye disease and retinal detachments can both cause vitreous hemorrhages as well. The vitreous hemorrhage is often given a chance to settle and attempt to reabsorb before surgery is scheduled. The severity of the initial disease before the pars plana surgery gives an indication as to what the level of vision will be after the surgery.

Procedure

• This procedure is usually done as an outpatient procedure. Either local or general anesthesia can be used during this procedure. At least three instruments are placed in the eye through the pars plana: one to remove the vitreous; another to inject fluid to help the eye maintain its shape while the vitreous is being removed; and one with a light source. The surgeon uses a microscope to view inside of the eye during the procedure. The eye is filled with a saline solution after all of the vitreous is removed. In some cases, the openings where the instruments were inserted are stitched shut; in others, the incisions don't need stitches and will heal on their own.

Risks

• Some of the risks of pars plana vitrectomy include infection, retinal detachment, increased eye pressure, vitreous hemorrhage and development of a cataract. Cataract is the most common adverse effect after vitrectomy procedures. Less common adverse effects include swelling of the tissue below the retina, a significant change in eyeglasses prescriptions and swelling in the center of the macula. The surgeon takes great care to avoid these outcomes and will also follow the patient closely after the procedure to manage these problems if they do arise.