Rather than being a single solid sphere, the eye is actually composed of several chambers. The largest of these chambers houses the vitreous humor or vitreous gel. The vitreous humor is normally a clear liquid that gives the eye its shape and structural support. Occasionally it becomes necessary to remove the vitreous humor for various reasons in a procedure known as a vitrectomy. While a vitrectomy is never entered into lightly, in some patients it is an important step in restoring the gift of sight.
Light that enters through the pupil at the front of the eye is bent through the natural lens and focused on the retina in the back of the eye. As light makes its way to the retina, it naturally passes through the aqueous humor in the front and the vitreous humor in the back of the eye. The vitreous gel, as it is sometimes called, is in physical contact with the retina. A vitrectomy involves removing that vitreous gel for one of a number of reasons.
Occasionally the retina may detach from the back of the eye or start to loosen, which can cause immediate and permanent blindness if not corrected surgically. In chronic conditions such as diabetes and high blood pressure, the retina can be destroyed over time and even hemorrhage. As blood enters the eye itself the vitreous humor, which is normally clear, can become cloudy or murky. Any light passing through the vitreous gel is impeded and visual acuity decreases. When patients need retinal surgery, a vitrectomy must be performed in order to remove the vitreous gel and allow surgeons direct access to the back of eye. In cases in which the vitreous gel is too cloudy to permit normal vision, a vitrectomy may be done to restore sight.
During a vitrectomy an eye surgeon, usually one who has specialized in retinal surgery, will make small incisions in the chamber that holds the vitreous gel and draw the fluid out under suction. After the retina has been reattached, a substance will be placed inside that chamber to replace the vitreous gel. This substance is usually a silicone based oil or even an air-gas mixture that restores the shape and structure to the eye without interfering with the path of light as it moves through the eye.
As mentioned before, the procedure is not chosen without careful consideration. In the case of bleeding into the vitreous gel, many surgeons will wait several months to a year to see if the fluid clears on its own rather than performing a vitrectomy. This is because the procedure has a relatively high rate of complication. While successful vitrectomy and subsequent securing of the retina can restore sight almost immediately, vitrectomy can lead to more bleeding into the space, increased pressure within the eye, infection inside the eye, and even further retinal detachment. Another challenging and difficult to treat consequence of a vitrectomy is that as the eye heals, new blood vessels form in the eye, which can block light and interfere with vision.
If you have a sudden loss of vision, trauma to the eye, or a slow clouding of your vision, it is important to see an eye doctor without delay. In the case of retinal detachment, your primary eye doctor can refer you to someone that has specialized in diseases and surgery of the retina and who is fully qualified to perform a vitrectomy.