VITRECTOMY
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In this operation they will remove the vitreum (= vitreous of the eye) weggehaald, because there are bleeding or because the vitreum pulls on the retina. Recently the vitreum is taken away when there is to much fluid around the retina.
WHEN OCCURS A VITRECTOMY ?
VITREOUS HEMORRHAGE
When the haemorrhage doesn't clear in 6 month, a vitrectomy is recommended, because the chance that the haemorrhage will go away spontaneous is little and because blood (on long term) is toxic for the retina.
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DIABETIC MACULAR EDEMA
The macula is the centrum of the retina, that is responsible for detailed vision. In diabetes may occur that the macula becomes fluid ("edema"), because of the leak from diseased arteries. This is the main cause of poor vision in diabetic patients. One distinguishes local and disseminated edema. The local edema can be treated with laser. Also a good regulation of blood sugar, bloodpressure and cholesterol are important. Also the optimalisation of heart- and kidney function should be pursued ("diffuus"). Recently there is interest in vitreous surgery. Many factors can cause edema. The sick retina produces Het zieke netvlies produceert immers bloodvessel-growth factors. These factors cause not only vascular leakage and edema but also "new vessel formation". These growth factors are accumulated in the vitreous, like a sponge. The present growth factors influence the structure of the vitreous and cause an adhesion and traction on the retina, what attracts additional moisture. By removing the vitreous, the sponge is removed (with accumulated growth factors) and the pull on the posterior pole is gone.
INFLAMMATION OF THE RETINA AND CHOROID ("uveitis")
Inflammatory factors may also accumulate in the vitreous. Thus, the inflammation also maintain. Analogy with diabetes, it is also usefull to remove the vitreous: the sponge with the accumulated inflammatory factors will be removed. That way the retina and the uvea are less stimulated. Moreover, the tension on the posterior pole is less!
HOLES IN THE RETINA (central or big lateral holes) with silicone-oil or gas the holes can be closed. When they use oil, the oil will have to be removed later!
MEMBRANES ON THE RETINA (“pucker”) the membrane will be peeled off
HOW IS A VITRECTOMY DONE?
The operation is done under LOCAL OR GENERAL ANESTHESIA and takes 30min to a few hours. A conduit, to moisture in the eye ("infusion"), is sewed on the eye (on the front side of the eye: "pars plana"). Two extra openings allow 2 instruments in the eye. The patient has to stay a few days in the clinic!
WHAT ARE DISADVANTAGES OF A VITRECTOMY
Accelerated CATARACTFORMATION is an unavoidable consequence of this intervention. This can be operated easily after a few years.
After a vitrectomy a DETACHED retina can always happen. This is even the main complication (3 - 5% of cases). This complication usually occurs the first 4 months after the surgery and requires a new vitrectomy.