It’s a frequent refrain from people who have undergone surgery to remove cataracts from their eyes…“Best thing I’ve ever done for myself!”…“Best money I’ve ever spent!” That’s because after years of struggling to see and with their vision having grown worse and worse, they’re now free of the cloudy, blurry, discolored visual effects caused by the thickening and stiffening of their natural lenses that occurred as they aged. In fact, for many people, it’s even better than that…After nearly a lifetime of wearing glasses or contacts from conditions such as astigmatism or presbyopia, their cataract surgery has left them with perfect or near-perfect vision and they are glasses-free for the first time in decades.
If you’ve heard such stories and have a cataract or two, you might be thinking, “Where do I sign up?” especially if you’ve also heard that the surgery is quick and painless, with a short recovery time. However, you may have also heard some talk about cataracts coming back. “If they come back anyway,” you may be wondering, “is cataract surgery worth the time, money, and discomfort after all?”
To better understand whether a person can really get cataracts after they’ve had surgery, it’s helpful to understand a little about what cataract surgery is and isn’t. People are often under the impression that, as we age, the eye’s natural lens develops some kind of film over it that gets progressively thicker and more difficult to see through clearly, and that that’s what a cataract is. They surmise that cataract surgery—often referred to as “having your cataract removed”—consists of cleaning off or clearing away that film that’s been blocking vision so that the person can see again, and that the film can build up on the lens again sometime down the road. This is incorrect.
The cataract is not a buildup on the lens, but rather a clouding of the lens itself once it reaches a certain deteriorated state. Throughout our lifetimes, our lenses continue to accumulate new cells on their perimeters, like rings on a tree. But a tree widens in diameter as this happens, and a lens does not. It remains at the same diameter, and the older cells get packed toward the center, with the lens’s protein fibers thickening and warping as this happens. That is what causes the distortion of vision associated with cataracts.
Therefore, once a cataract has developed far enough to make daily living difficult, the only way to treat it is to remove the lens altogether and replace it with a synthetic one called an intraocular lens (IOL). All cataract surgeries do this same thing in some fashion.
Once you have an artificial lens in your eye, you no longer need to worry about its fibers thickening and becoming distorted, because your new IOL will not grow new cells the way that your original, natural lens did. The entire process by which your cataract initially formed is thus rendered moot. So why, then, do people talk about cataracts returning after surgery?
When people talk about cataracts “coming back,” they’re referring to the development of something called a secondary cataract. The process by which secondary cataracts develop is completely different from what causes primary cataracts.
Here’s how it works. The eye’s natural lens is not located in the front of the eye but rather behind the cornea and pupil. As light rays pass through the lens, the lens flexes to bring an image into focus. The light then travels deeper into the eye to the retina, where the image is converted into visual data that travels to the brain along the ocular nerve. The lens resides within a “capsule” or thick membrane called the posterior lens capsule, which the surgeon must cut into to take the lens out and replace it with an IOL.
Sometimes, unfortunately, trouble develops when epithelial lens cells remain behind in the posterior lens capsule after surgery. Epithelial cells are not the same as the fibers that constitute the main body of the lens that is removed by the surgeon. They have a number of important functions, including lens growth and development, protecting the lens from damage, and transporting fluids. The fibrous body of the lens is surrounded by a thin layer of these epithelial cells.
Epithelial cells that remain behind in the posterior lens capsule after surgery might proliferate to the point where they form a cluster between the IOL and the retina. Now when light penetrates the IOL, it becomes partially blocked or distorted by the clump of epithelial cells before it reaches the retina. This usually takes years to develop, but in some cases it happens within months of surgery to treat primary cataracts. The condition is known as posterior capsule opacification or, more commonly, secondary cataract. It may occur in up to 20% of cataract-surgery patients.
The symptoms of a secondary cataract are very much like those of a primary cataract, which is why people often feel like their cataract has “come back.” They might start to see glares or halos around lights, discoloration, and blurred or hazy images. They might go back to having trouble seeing objects up close or far away.
Fortunately, secondary cataracts are eminently treatable, so if someone begins to experience cataract symptoms following surgery, they should immediately make an eye appointment so their doctor can take a look. Getting rid of a secondary cataract is even easier than surgery for a primary cataract. The physician uses a laser to bore a tiny hole in the center of the posterior capsule, breaking up the secondary cataract (that is, the clump of epithelial cells). This provides a clear path for light to travel from the lens to the retina. This only takes a few minutes and is painless. Afterward, vision is restored and the person may immediately resume normal activities.
You may now be wondering, “Yes, but how many times can you get a secondary cataract?” Normally, it only happens once per eye. It’s possible for someone to develop posterior capsule opacification twice in the same eye, but it’s so rare that the cases get written up in medical journals when it happens.
