Pars plana vitrectomy is a surgical procedure which is performed in the operating room. It may be performed under twilight (monitored anesthesia care) or general anesthesia.
The retina specialist places 3 small ports that are less than 1mm in size through the white of the eye and into the vitreous cavity. Fluid is infused into the vitreous cavity while the surgeon uses a vitrectomy probe to carefully removes the vitreous. The surgeon meticulously visualizes and separates the network of scar tissue into smaller segments. The smaller segments are separated from the vitreous (gel) and carefully removed. Laser is applied carefully throughout the retina to decrease the risk of new blood vessels developing. The scar tissue is typically very adherent to the retina, and retinal tears may form when removing the tissue. Retinal tears are lasered and the eye may then be filled up with either absorbable gas or silicone oil. No gas or oil is required if there are no retinal tears.
The eye is then patched and a shield is placed on the eye. The patient may be asked to maintain a specific position for approximately 7 days if there is a retinal tear. The surgery is not typically very painful. Tylenol is all that is usually needed for pain.
More about gas and silicone oil.
The purpose is to allow the gas or oil to move into a position that it covers the retinal tears, and prevents fluid from collecting underneath it while the retinal laser takes effect.
There are two different types of self-absorbing gas: SF6 and C3F8. SF6 typically lasts approximately 2 weeks and C3F8 approximately 6-8 weeks. Patients will notice a clear area at the top of their visual field which represents the area of retina not covered by the gas bubble. This area will become larger over time until the gas bubble no longer covers the area of central vision. At this point, the central vision will slowly become clearer. This process will occur until the gas bubble resolves completely. The central vision is typically decreased or distorted if it was affected by the retinal detachment. This typically improves slowly over a period of several months.
It is not possible to see through the gas bubble. The gas bubble will resolve over a period of several weeks. The central vision will become clearer (if pre-operatively involved by the retinal detachment) over several weeks to months. If the central vision is not involved, the primary visual improvement will be an improvement in the peripheral vision whch was previously affected by the retinal detachment.
Patients may not travel to high altitudes or fly when they have a gas bubble in the eye. The gas bubble expands rapidly in high altitudes causing high eye pressure and blindness.
Silicone oil is a great choice for patients who need a longer acting agent to prevent retinal re-detachment. It is not self-absorbing and may be removed safely at a later date. It is difficult to see through silicone oil and the vision is typically limited with the silicone oil in the vitreous cavity. The vision typically improves with removal of the silicone oil, but may be limited due to underlying damage from the pre-existing diabetic changes.