By Igor Westra M.D.
I am often asked what the vitreous is, what it does and why we remove it. The gel in that fills the eye is called the vitreous. Its purpose is to help the eye form during prenatal development. Afterwards it is supposed to stay clear. But after 18 years on the planet the gel starts to liquify just like that bowl of jello that has been in the refrigerator too long. The vitreous gel is surrounded by a thin membrane that forms a sac. Eventually the bag of gel becomes a bag of fluid much like a water balloon. At some point the bag breaks and the fluid rushes out. During this time the patient experiences floaters which are the pieces of the vitreous bag. The patient can also experience flashes if the bag pulls on the retinal tissue. These normally subside within a month or two. Problems occur when the bag gets stuck on the retina and tears it. The retina has the strength of wet tissue paper. Once there is a tear or hole in the retina there is a very high likelihood that the retina detaches which untreated leads to blindness. When patients have symptoms of flashes and floaters it is crucial to get the retina evaluated to rule out tears or detachment.
If the retinal tear is not repaired and the retina detaches then the next step often is surgery at the hospital. Vitrectomy surgery is the removal of the vitreous and its sac. This is replaced with a man made fluid initially and then this is replaced with a gas bubble or an oil bubble.These push against the retina and hold it in place to allow it to heal much like a cast on a broken bone.
The vitreous can also cause problems before it breaks up in diabetic patients. Abnormal blood vessels grow into the vitreous from the diabetic eye and the gel facilitates this process. Removing the vitreous makes it more difficult for the blood vessels to grow and cause blindness. If there is bleeding in the eye, it clouds up the vitreous and vitrectomy surgery is done to clear the vision.
Another curious problem caused by the vitreous is a macular hole. The macula is the center of vision, the part that does the fine seeing. In some people the vitreous is too sticky and gets stuck on the macula and then tears a hole there. This used to lead to very poor vision until it was discovered that removing the vitreous and filling the eye with gas or oil can allow most of the hole to heal. The very center is damaged but the vision is often quite good.
Vitrectomyis a very versatile, vision saving surgery usually done as outpatient surgery. Vitreous surgery has been around for about forty years and has become increasingly safe and effective. Often no sutures are required and most patients have little discomfort. As with many treatments, the key to success is timely intervention.