Vitrectomy

Vitrectomy is a surgery to remove some or all of the vitreous humor from the eye. Anterior vitrectomy entails removing small portions of the vitreous from the front structures of the eye - often because these are tangled in an intraocular lens or other structures. Pars plana vitrectomy is a general term for a group of operations accomplished in the deeper part of the eye, all of which involve removing some or all of the vitreous - the eye's clear internal jelly.

Pars plana vitrectomy

Originated by Robert Machemer [Machemer R. "The development of pars plana vitrectomy: a personal account." "Graefes Arch Clin Exp Ophthalmol." 1995 Aug;233(8):453-68. PMID 8537019.] and facilitated by Thomas M. Aaberg, Sr in late 1969 and early 1970, the original purpose of vitrectomy was to remove clouded vitreous - usually containing blood.The success of these first procedures led to the development of techniques and instruments to remove clouding and also to peel scar tissue off the light sensitive lining of the eye - the retina - membranectomy, to provide space for materials injected in the eye to reattach the retina such as gases or liquid silicone, and to increase the efficacy of other surgical steps such as scleral buckle.

An explosion of new instruments and surgical strategies through the 1970s and 1980s was spearheaded by surgeon/engineer Steve Charles, M.D. [Wang CC, Charles S. "Microsurgical instrumentation for vitrectomy: Part II." "J Clin Eng." 1984 Jan-Mar;9(1):63-71. PMID 10265855.] More recent advances have included smaller and more refined instruments for use in the eye, the injection of various medications at the time of surgery to manipulate a detached retina into its proper position and mark the location of tissue layers to allow their removal, and for long term protection against scar tissue formation.

Additional surgical steps

Additional surgical steps involved as part of modern vitrectomy surgeries may include:

Membranectomy - removal of layers of unhealthy tissue from the retina with minute instruments such as forceps (tiny grasping tools), picks (miniature hooks), and visco-discection (separating layers or tissue with jets of fluid.)

Fluid-gas exchange - injection of gas into the eye such as sulfur hexafluoride or perfluoropropane to hold the retina in place or temporarily seal off holes in the retina. These gases disappear spontaneously once they have accomplished their purpose.

Silicone oil injection - filling of the eye with liquid silicone to hold the retina in place.

Photocoagulation - laser treatment to seal off holes in the retina or to shrink unhealthy, damaging blood vessels which grow in some diseases such as diabetes.

Scleral buckling - placement of a support positioned like a belt around the walls of the eyeball to maintain the retina in a proper, attached position.

Lensectomy - removal of the lens in the eye when it is cloudy (cataract) or if it is attached to scar tissue.

Indications

Conditions which can benefit from vitrectomy include:

Vitreous floaters - deposits of various size, shape, consistency, refractive index, and motility within the eye's normally transparent vitreous humour which can obstruct vision. Here pars plana vitrectomy has been shown to relieve symptoms [Roth M, Trittibach P, Koerner F, Sarra G. " [Pars plana vitrectomy for idiopathic vitreous floaters.] " "Klin Monatsbl Augenheilkd." 2005 Sep;222(9):728-32. PMID 16175483.] , however, because of possible side effects it is only used in severe cases.

Retinal detachment - a blinding condition where the lining of the eye peels loose and floats freely within the interior of the eye. Steps to reattach the retina may include vitrectomy to clear the inner jelly, scleral buckling to create a support for the reattached retina, membranectomy to remove scar tissue, injection of dense liquids to smooth the retina into place, photocoagulation to bond the retina back against the wall of the eye, and injection of a gas or silicone oil to secure the retina in place as it heals.

Macular pucker - formation of a patch of unhealthy tissue in the central retina (the macula) distorting vision. Also called Epiretinal membrane. After vitrectomy to remove the vitreous gel, membranectomy is undertaken to peel away the tissue.

Diabetic retinopathy - may damage sight by either a non-proliferative or proliferative retinopathy. The proliferative type is characterized by formation of new unhealthy, freely bleeding blood vessels within the eye (called vitreal hemorrhage) and/or causing thick fibrous scar tissue to grow on the retina, detaching it. Often diabetic retinopathy is treated in early stages with a laser in the physician's office to prevent these problems. When bleeding or retinal detachment occur, vitrectomy is employed to clear the blood, membranectomy removes scar tissue, and injection of gas or silicon with scleral buckle may be needed to return sight. Diabetics should have an eye exam yearly.

Macular holes - the normal shrinking of the vitreous with aging can occasionally tear the central retina causing a macular hole with a blind spot blocking sight.

Vitreous hemorrhage - bleeding in the eye from injuries, retinal tears, subarachnoidal bleedings (as Terson syndrome),or blocked blood vessels. Once blood is removed, photocoagulation with a laser can shrink unhealthy blood vessels or seal retinal holes.

Complications of vitrectomy

Along with the usual complications of surgery, such as infections, vitrectomy can result in retinal detachment. A more common complication is high intraocular pressure, bleeding in the eye, and cataract, which is the most frequent complication of vitrectomy surgery. Many patients will develop a cataract within the first few years after surgery. [cite journal |author=Benson WE, Brown GC, Tasman W, McNamara JA |title=Complications of vitrectomy for non-clearing vitreous hemorrhage in diabetic patients |journal=Ophthalmic surgery |volume=19 |issue=12 |pages=862–4 |year=1988 |pmid=3231410 |doi=]

Recovery after vitrectomy

Patients use eye drops for several weeks or longer to allow the surface of the eye to heal. In some cases heavy lifting is avoided for a few weeks. A gas bubble may be placed inside the eye to keep the retina in place. If a gas bubble is used, sometimes a certain head positioning has to be maintained, such as face down or sleeping on the right or left side. It is very important to follow the physician’s specific instructions. The gas bubble will dissolve over time, but this takes several weeks. Do not fly while the gas bubble is still present. Problems such as return of the original condition, bleeding or infection from the surgery may require additional treatment or can result in blindness.

Vision after vitrectomy

The return of eyesight after vitrectomy depends on the underlying condition which prompted the need for surgery. If the eye is healthy but filled with blood, then vitrectomy can result in return of 20/20 eyesight. With more serious problems, such as a retina which has detached several times, final sight may be only sufficient to see to safely walk (ambulatory vision) or less.

Cultural references

In 1996, Spalding Gray (June 5, 1941 – ca. January 10, 2004), an American actor, screenwriter and playwright,released "Gray's Anatomy", a film monologue describing his experiences dealing with a macular pucker and his decision to undergo surgery.

References

ee also

*Eye surgery