When Do Your Eyes Need a Vitrectomy or Membrane Peel?
The procedure can improve vision by removing growths from the retina
En español | After I had a retinal tear repaired, I returned to my retina specialist for a follow-up visit, where I told him that I'd noticed some visual distortion and blurred vision, including a diminished ability to recognize faces — so much so I'd wondered if I might be suffering from face blindness (a condition known as prosopagnosia).
He pointed to a spot on the OCT (ocular coherence tomography) scan of my eye, and said, “See this dip? That is causing your vision distortion in that eye.”
He told me I had an “epiretinal membrane pucker” — also called cellophane maculopathy or macular pucker — which is a puckering on the retina caused by a fibrous membrane developing over its center, the macula, then contracting. This can impair your vision.
How the problem develops
Your retina is that very thin layer of light-sensitive nerve tissue that lines the back of your eye and covers the gel (vitreous) inside your eyeball. The retina's job is to focus images coming through the front of your eye and convert them into electrical impulses that are then transmitted by your optic nerve to your brain, allowing you to see.
It's very common for an epiretinal membrane (ERM) to develop, especially as we age, says Carl Awh, a retina specialist and president of the American Society of Retina Specialists (ASRS). “In most eyes that membrane is so thin and so clear that it has no impact on vision,” he notes.
But in a small percentage of eyes, over time, this membrane can thicken and then contract, distorting vision. While this can be caused by scarring from the laser repair of a retinal tear, it is “more likely the scarring from the tear itself,” Awh says. Or it may simply be due to the aging process. Or it may be “idiopathic,” meaning its origin is unknown. Studies have shown that 2 percent of patients over 50, and 20 percent of patients over 75, have some degree of ERMs, according to the ASRS. Women and men are affected equally, and in 10 to 20 percent of cases both eyes have some degree of ERMs. Most, however, don't need treatment.
Rarer causes of ERMs can be diabetes, venous occlusive disease, trauma after ocular surgery or inflammation inside the eye.
What you will most likely notice, says Timothy Murray, a retina specialist and past president of ASRS, is a distortion in your vision, sensitivity to light, blurry vision, and/or loss of fine details while reading, and a diminished ability to recognize faces — all of which I experienced.
To check for this, he suggests closing one eye, and noting if things look out of whack. Do things like telephone poles or window blinds deviate from a straight line? Is the vision in the open eye noticeably blurry? Check the vision of one eye against that of the other.
When to seek help
After an initial growth period, ERMs may become fairly stable, Awh notes, and your doctor can simply monitor them to make sure they don't get worse.
In rare cases, ERMs spontaneously release from the retina, relaxing the “pucker,” and normal vision returns.
But if your vision becomes significantly affected, it may be time to consider surgery — a vitrectomy — to remove the ERM. And the sooner, the better because chances for a good result on a new pucker are much better than on one that has existed for some time.
With your eyes dilated, an OCT imaging device is used to produce a very clear cross-section picture of the ERM. (Sometimes additional testing, like fluorescein angiography, is used to determine if other underlying retinal problems have caused the ERM.)
Experts note that there aren't any medications, like eye drops or nutritional supplements, that will improve ERMs or make them disappear. Surgery is the only remedy.
This surgery is usually done in an outpatient surgical center by a retina specialist. In most cases, the procedure in done under local monitored anesthesia, while you are awake. Some local anesthesia will be administered around the eye to numb it.
Using extremely small-gauged instruments and special magnification to perform this very delicate surgery, the retina specialist starts by making three microscopic incisions in the white of the eye to access the gel, or vitreous, cavity behind the eye's lens and in front of the retina. The three incisions, or ports, Murray explains, allow the retina specialist to: (1) put saline solution into the eye to keep it inflated during surgery; (2) insert a light pipe into the eye; and (3) allow the doctor to introduce micro forceps, which will be used to gently “peel” or remove the ERM. These incisions, Awh notes, are so small they are usually self-sealing and don't require sutures.
With the newest techniques and instruments, Murray says, the retinal specialist can now delicately remove a second layer, too, the internal limiting membrane (ILM), beneath the ERM, in patients who have a more advanced ERM. This, he says, prevents the ERM from recurring.
Total surgery time is usually less than one hour.
A side benefit of the vitrectomy is that when the gel inside the eye is removed and replaced with saline solution, any existing floaters and debris are also eliminated. Within 24 hours, Awh points out, the body replaces the saline solution with its own fluid.
After the surgery, a patch is placed over the eye, and the patient returns the following day for its removal and an initial exam. The white of the eye will be red for about a week.
Vision recovery, Awh says, is slow. “The vision on day one is typically a little worse than when the patient arrives. It takes most patients a few days to get back to their baseline vision.” Most patients see an improvement within three months, and it usually takes a year for maximum vision improvement.
More precisely, Awh says, “There isn't great data for vision improvement because many aspects of vision are subjective, such as decreased distortion. Most studies measure improvement in visual acuity (for example, what line on the eye chart a patient can read). I think it's safe to say that 80 to 90 percent of patients will ultimately have improved vision. Those who don't improve typically maintain stable vision, which is a better outcome than the progressive decline in vision that accompanies some macular ERMs.”
Risks and complications
Experts describe the risk factors for the vitrectomy as small, but caution that the surgery does increase cataract progression for patients who still have their natural lens. “Many patients will need cataract surgery within a year,” Awh adds.
About 1 in 100 patients develop a retinal detachment, which will need to be repaired. And 1 in 2,000 patients get an infection in the eye, which can be treated with antibiotics.
Finding a retina specialist
• Consult the American Society of Retina Specialists website, asrs.org. Click the “Find a Retina Specialist” at the top left to locate a doctor in your area.
• Ask the right questions. It's always important to feel confident in the retina specialist you select; and it is always a good practice to get a second opinion. And ask the specialist:
- How many vitrectomies have you performed?
- How many complications have your patients experienced?
- How often do your patients suffer eye infections as a result of the surgery?
• Don't schedule your surgery unless you are satisfied with the answers.