Vitrectomy and membranectomy

Tuesday, November 10th, 2009 at 1:40 pm Post in Eye Diseases

In most cases, a surgery is particularly for one certain eye disease. Vitreoretinal eye surgery (vitrectomy) is an exception that it can restore, preserve and enhance vision for many eye conditions such as certain types of age-related macular degeneration, diabetic retinopathy, diabetic vitreous hemorrhage, macular hole, retina detachment, epiretinal membrane, CMV retinitis, proliferative vitreoretinopathy, endophthalmitis, intraocular foreign body removal etc…

Only a general ophthalmologist who specializes in the medical and surgical management of vitreoretinal disorders is entitled to perform a vitreoretinal surgery. Other ophthalmologist sub-specialists and optometrists usually refer patients who need a vitreoretinal surgery to a specialist mentioned above. During the procedure, the surgeon will remove the vitreous humor and clear the inner chambers in the eye. Since vision distortion and vision loss are caused by the shadows casted by the foreign matter in the vitreous humor, the procedure replaces natural vitreous humor with injected saline liquid.

After making a general anesthesia, the surgeon makes three tiny incisions in the eye to create openings for three instruments’ insertion: light pipe, infusion port and vitrector. These three incisions are located behind the iris but in front of the retina. Light pipe is used as a microscopic, high-intensity flashlight, and infusion port uses a saline solution to maintain normal IOP. The vitrector is just the cutting device that removes vitreous humor.

After a vitreoretinal surgery, you are likely to take antibiotic and anti-inflammatory eye drops during the following several weeks. Potential complications such as bleeding, infection, cataract progression and retinal detachment are rare. Vitrectomy has a very high success rate, so that most patients after a vitrectomy can receive a significant vision improvement. But the final visual outcome can be clear after quite a few weeks.

Also known as macular pucker and cellophane retinopathy, epiretinal membrane (ERM) involves growth of a membrane across the retina, which interferes with central vision by distorting the central retina. ERM is usually associated with other disorders such as previous retinal detachment, uveitis, retinal tears, BRVO and CRVO. People with a clear ERM should receive an epiretinal membrane peeling procedure (membranectomy).

After a vitrectomy, the vitreoretinal surgeon grasps and peels away the membrane from the retina with an extremely fine forceps and diamond-dusted instruments. And sutures may be used to close the incision. The recurrent rate of an ERM is 10% and 80% to 90% patients after a membranectomy will experience visual improvement. Potential complications of membranectomy are almost the same as that of a vitrectomy.

Proliferative vitreoretinopathy (PVR) is the growth of cellular membranes within the vitreous cavity and on the front and back surfaces of the retina. PVR is always associated with a retinal hole or break and exerts traction on the retina, probably leading to a second retinal detachment. These contracting membranes of PVR can cause severe visual distortion and require a PVR surgery, which involves a pars plana vitrectomy and a membrane peeling procedure. The vitrectomy is used to remove the vitreous humor and the membranectomy strips away the contracting membranes on the retinal surface. An additional buckling procedure can be performed to help repair the damaged area and a laser treatment may be needed to help close retinal breaks. Visual recovery after a PVR surgery may take many months.