vitrectomy(redirected from enzymatic vitrectomy)
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Vitrectomy is the surgical removal of the vitreous (transparent gel that fills the eye from the iris to the retina).
The bulk of the contents of the eyeball is a clear jelly-like substance that is susceptible to several afflictions that impair vision by damaging its transparency.
- Bleeding, particularly from diabetic retinopathy
- Blood vessels growing into the vitreous, again due to diabetes.
The retina is the light-sensitive membrane that receives images and transmits them to the brain. It covers the inside of the back of the eye. On occasion the retina will fall into the vitreous, a condition called retinal detachment. This may be due to disease in the vitreous that pulls the retina inward, small tears in the retina that allow liquid to seep behind it and push it forward, or injury to the eye that simply breaks the retina loose. It may be necessary to remove the vitreous in order to replace the retina and restore vision.
Using instruments suited for microscopic surgery, the ophthalmologist (eye surgeon) penetrates the eyeball, aspirates the vitreous, and replaces it with saline. The saline replaces the vitreous at a constant pressure in order to keep the eye from collapsing. Once the saline is in place, both eyes are patched. The procedure takes two to three hours to complete.
Because this is a major operation on the eye, the surgeon will perform a very extensive evaluation of both eyes. After looking inside with a variety of lenses, a CT, MRI, or ultrasound study may be needed. Immediately prior to the vitrectomy, the pupils will be dilated.
Eye drops and antibiotics are administered, and eye rest is advised until healing is completed.
Risks associated with vitrectomy are retinal detachment, bleeding, iatrogenic (medically caused) cataracts, and endophthalmitis (inflammation of the eyeball).
Vision is restored to useful levels in two-thirds of patients.
O'Malley, Conor. "Vitreous." In General Ophthalmology, edited by Daniel Vaughan, 13th ed. Stamford: Appleton & Lange, 1993.
Computed tomography (CT scan) — Computerized method of creating images of internal organs using x rays.
Diabetic retinopathy — Disease that damages the blood vessels in the back of the eye caused by diabetes mellitus.
Endophthalmitis — Inflammation of the eyeball.
Iatrogenic — Inadvertently caused by medical treatment.
Magnetic resonance imaging (MRI) — Computer ized method of creating images of internal organs using magnetic fields.
Saline — A salt solution equivalent to that in the body—0.9% salt in water.
surgical removal of a diseased vitreous of the eye. Vitreous strands are cut with a specially designed infusion cutter that delivers a physiologic solution (e.g., Ringer's solution) to maintain intraocular pressure, and withdraws the diseased vitreous by suction. Almost half of all vitrectomies are done for the treatment of diabetic retinopathy in order to prevent blindness. It also may be done for treatment of vitreous hemorrhage due to other causes, such as penetrating injuries to the eye, hemolytic glaucoma, central vein occlusion, and some forms of retinal detachment.
Removal of the vitreous by means of an instrument that simultaneously removes vitreous by suction and cutting, and replaces it with saline or some other fluid.
[vitreous + G. ektomē, excision]
vitrectomy/vi·trec·to·my/ (vĭ-trek´tah-me) surgical extraction, usually via the pars plana, of the contents of the vitreous chamber of the eye.
n. pl. vitrecto·mies
Surgical removal of the vitreous humor from the eyeball.
Etymology: L, vitreus, glassy; Gk, ektomē, excision
a surgical procedure for removing the contents of the vitreous chamber of the eye, which are then replaced by oil, air, or a vitreous substitute.
vitrectomyOphthalmology A procedure in which the vitreous is removed to operate on the retina. See Diabetic retinopathy.
Removal of the vitreous by means of an instrument that simultaneously removes vitreous by suction and cutting and replaces it with saline or some other fluid.
[vitreous + G. ektomē, excision]
vitrectomyAn ophthalmic operation to remove part or all of the VITREOUS BODY of the eye.
Removal of the whole or a portion of the vitreous humour and replacement by saline or, more commonly, silicone oil. Indications for this surgical intervention include persistent vitreous opacities (usually as a result of unabsorbed haemorrhage), severe penetrating trauma, luxation of the lens, retention of some foreign bodies which cannot be removed with a magnet, endophthalmitis, and especially advanced diabetic eye disease such as proliferative retinopathy to prevent retinal detachment because the fibrovascular network of the retina tends otherwise to adhere to the vitreous body. See intravitreal injection.
surgical removal of a diseased vitreous of the eye.
removal of vitreous present in the anterior chamber.
pars plana vitrectomy
removal of vitreous by aspiration through a needle inserted over the pars plana ciliaris.