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Vitreous Surgery
Vitreous surgery is a relatively new type of microsurgery developed in recent years which now enables eye surgeons to treat patients with diseases of the retina and vitreous. Patients who, until the advent of this type of surgery, might have been considered hopelessly blind. This pamphlet has been prepared to provide a basic understanding of vitreous surgery, the indications for surgery, and the kinds of things a patient undergoing this treatment can expect.
The vitreous is a watery gel that fills the eye from the lens back to the retina. It is 99% fluid but contains tiny fibers that are attached to the retina and optic nerve. These fibers can usually only be seen with a microscope. The normal vitreous is totally clear and allows the light from the front of the eye to reach the retina undisturbed.
The retina is a thin layer of nerve tissue that lines the back of the eye. It receives light signals coming in from the front of the eye and sends them on to the brain so that vision can occur. The small specialized area of the retina called the macula is responsible for all the fine visual tasks (ie. reading vision). The rest of the retina provides peripheral (side) and night vision.
Indications for Vitreous Surgery
When the normally clear vitreous gel becomes mixed with blood or scar tissue, the incoming light can no longer reach the retina and vision is often markedly decreased. There are a number of eye diseases which can cause bleeding into the vitreous; the most common is diabetes. Another common condition is a blocked retinal blood vessel. In both of these conditions, new, fragile blood vessels develop or proliferate on the surface of the retina or optic nerve and grow into the vitreous gel. These abnormal blood vessels often break and bleed into the vitreous (vitreous hemorrhage) blocking out the incoming light and severely decreasing vision. When bleeding is minimal the eye can usually reasorb the blood and the vision will usually clear. At other times, however, the blood may not clear or scar tissue may form in the area of new blood vessels and old blood. As the scar tissue shrinks it may pull the retina loose causing more distortion and visual loss, which is known as a traction retinal detachment.
A third cause of vitreous hemorrhage is a retinal tear and detachment. In this condition the fibers in the vitreous gel pull on the retina tearing a hole which allows the watery gel to percolate behind the retina and lift it off the back of the eye.
This is sometimes accompanied by torn blood vessels and bleeding or the formation of strands of scar tissue forming in the vitreous or on the surface of the retina which exerts a pulling force on the retina. When scar tissue has formed, routine eye surgery for a torn or detached (loose) retina is usually not enough and more specialized vitreous surgery is required. The vitreous is removed as well as the scar tissue which has formed in front and sometimes behind the retina. In some patients without any other eye problems, a thin layer of scar tissue forms on the retina in the center vision area. This "membrane" distorts and blurs the reading vision. With vitreous surgery this membrane can be peeled off the retina.
There are rare occasions when, after cataract surgery, an infection develops inside the eye. This condition, called endophthalmitis, can have devastating consequences. Before vitrectomy surgery many of these eyes were lost. Today, a vitrectomy can be performed and antibiotics placed directly inside the eye offering a much better chance of preserving vision.
Still another less common indication for vitreous surgery is a severe injury to the eye, either through blunt trauma or a penetrating injury such as a metal foreign body.
In general, the purpose of vitreous surgery is to remove the abnormal vitreous as well as any scar tissue that may be present. This allows incoming light to reach the retina undisturbed and the retina to assume its normal position if it has been pulled up or torn loose.
Treatment
The first step in treating patients with vitreous and retinal diseases is a thorough eye examination. If the vitreous jelly is opaque, specialized tests such as an ultrasound may be necessary to evaluate the status of the eye and the retina's potential to function. If, after this examination, the surgeon feels the eye has a possibility of regaining useful vision, vitreous and retinal surgery can be performed.
Working under a microscope, tiny instruments are introduced into the eye through openings made to the side of the clear cornea. The instruments pass behind the iris (colored portion of the eye) and the lens, into the vitreous cavity.
The cloudy vitreous is removed and replaced with a special clear saline solution. In addition, scar tissue is cut and removed in an attempt to relieve the pulling on the retina. Laser and other special techniques are often used at the time of surgery. Magnets on the tip of a probe can be used to remove metallic foreign bodies. Air or special gasses may be used to keep the retina in place until healing takes place. A cataract, if present, can be removed; although often this will be left for removal at a later time when a plastic intraocular lens can be inserted. A retinal detachment, if present, is treated at the same time by draining out the fluid from under the retina and securing a band around the eye called a scleral buckle to help support the torn retina during the healing stages.
What to Expect
Some of even the most complicated vitrectomy surgeries are carried out as day (outpatient) surgeries. A general physical checkup is often required and perhaps a chest x-ray, electrocardiogram, blood and urine tests. The purpose of these tests is to alert the doctors to potential health problems.
The anesthesia is usually local for eye surgery. Local anesthetic is given with an injection of a numbing solution behind the eye and the patient is drowsy but awake during the surgery. Little or no pain is experienced as sedation is given prior to the injection. On occasion general anesthesia is required and with this the patient is asleep during the entire operation. The surgery will take from one to four hours.
Following surgery you will be moved to the recovery room where specialists will monitor your vital signs. There is usually little or no pain following the surgery. Medication will be ordered for pain when necessary. Many patients may be able to go home the same day of surgery, while others may stay in the hospital one or more days. After surgery, the eye will be patched for one or two days and drops will be administered four times during the day. The eye may feel scratchy due to the tiny sutures used during surgery. Those patients who have had air or gas injections into the eye during the vitrectomy, will be asked to maintain a fixed head position for a number of days until the air or gas has been absorbed by the body. No airplane travel is allowed until all the air or gas is absorbed. However, in just about all cases patients will be able to be up and out of bed the day after surgery.
The vision will probably remain blurred for weeks to months. This is normal and it may take a number of months before the vision stabilizes. You will be encouraged to begin using the eye shortly after surgery, however, it will tire quickly. Reading, writing and watching TV are acceptable but the eye will need rest frequently. You should NOT touch or rub your eye. If this should be too uncomfortable merely replace the eye patch for a short period of time.
Returning Home
When you leave the hospital you will be given eye drops and told how to use them. Prescriptions for antibiotic pills and pain medication will also be given. An appointment will be made for you to return to our office for postoperative follow-up. The routine you followed in the hospital will be followed also when you return home. You can resume washing your hair in the shower about two weeks after surgery; sometimes earlier if a patch is worn and care is taken not to soak the patch. You may gradually resume normal activities at the direction of your surgeon. In general, you may resume desk work when reading is comfortable but strenuous physical labor must be delayed.
