Vitreous surgery, vitrectomy, is a surgical procedure where the jelly-like material within the eye is removed. Its removal is not 100%, due to its structure in relation to the retina near the front part of the eye, and also due to the presence of the natural lens within the eye.
The removal of the vitreous is necessary in order to approach the back of the eye to repair macular holes and macular puckers, resolve vitreo-macular traction syndrome, and remove sub-macular blood. Vitrectomies are also used to clear blood in the eye and other vitreous opacities, and certain types of retinal detachments, especially those detachments associated with scar tissue formation. It is also necessary in many cases involving intraocular foreign bodies and eye trauma.
How are Vitrectomies Performed?
In order to perform a vitrectomy, three to four small stab incisions, sclerotomies, are made into the eye through a save zone approximately 3-4 mm away from the colored part of the eye. These small openings may be kept open with small cannulas and are the entry sites for the several instruments which are placed into the eye in order to perform the surgery. The first opening is used to infuse fluid into the eye. If this were not done the eye would collapse as vitreous is removed from within the eye. The other 2 or 3 openings are for a light source and working instruments. One of the instruments is a vitrector, which cuts and aspirates the vitreous out of the eye. It can do the same for scar tissue and any other soft material, which may be in the eye and require removal. Other instruments include tissue manipulators, aspirators, injectors, diathermy/cautery devices, scissors and forceps.
Using the vitrector, the vitreous is removed, and with the other instruments scar tissue is dissected off the retina and removed. Large foreign bodies are removed with forceps though enlarged sclerotomies.
In the past it was routinely necessary to close the sclerotomies with sutures, but instrumentation has become more refined resulting in very small sclerotomies, which close spontaneously. This has also resulted in less trauma to the eye and shorter recovery time.
What Complications Can Occur With Vitrectomy Eye Surgery?
Like all surgery, there is a potential for unexpected bleeding or infection. With regard to the eye, the bleeding can occur in different locations and different degrees of severity. Hemorrhages on the surface of the retina are controlled by increasing the infusion pressure and/or with diathermy/cautery. Hemorrhaging under the retina is much more ominous and may require heroic measures to salvage the eye. Infections are initially treated prophylactically with antibiotics around the eye, but intraocular post vitrectomy infections require injections of antibiotics into the eye, and occasionally, repeat vitrectomy.
Specific to the eye, there is the potential for a retinal detachment, an exacerbation scar tissue formation, increase in eye pressure, and inadvertent retina damage. Each of these problems is handled as they occur in the manner appropriate to the problem.
The complications mentioned above are the major ones which may result in significant loss of vision. Although the complication rate for vitrectomies is less than a 5%, compared to cataract surgery, which is less than .01%, this is high by a factor of 500. Considering that without vitreous surgery, most eyes would be lost, this success rate is very favorable.