A cataract is a clouding of the eye’s natural lens, which sits just behind the iris and pupil. This clouding scatters the light entering the eye, leading to blurred or hazy vision and increased glare. Once a cataract forms, it progresses, and surgical removal is the only way to restore clear sight. The question that often arises after successful surgery is whether the original condition can ever reappear.
How Cataract Surgery Works
Cataract surgery removes the physical cause of the clouding. The surgeon makes a tiny incision to access the lens, which is encased in a thin, clear membrane called the lens capsule. Using a technique called phacoemulsification, an ultrasound probe breaks the clouded natural lens into small pieces, which are then suctioned out of the capsule.
The lens capsule is deliberately left intact because it provides a stable, natural pocket to hold the replacement lens. A clear, artificial lens, known as an Intraocular Lens (IOL), is folded and inserted into this empty capsule where it unfolds and remains permanently. Since the original biological material that formed the cataract is completely removed from the eye, the true cataract cannot regrow.
What Is Mistaken for a Returning Cataract?
While the original cataract cannot come back, vision loss can occur months or even years after the procedure due to a condition often called a “secondary cataract” by patients. The correct medical term for this issue is Posterior Capsule Opacification (PCO), and it is the most frequent complication following cataract surgery. PCO develops when the clear capsule supporting the new lens becomes cloudy.
During the initial surgery, some microscopic lens epithelial cells (LECs) can remain on the inside of the capsule. These cells can proliferate and migrate across the posterior, or back, portion of the lens capsule. This cellular growth causes the membrane to become thickened and opaque, much like a foggy window.
The symptoms of PCO are nearly identical to those of the original cataract, including fuzzy vision, reduced contrast sensitivity, and trouble with glare. PCO typically affects about 10% of patients, though the incidence can be higher depending on the type of IOL used or if a patient has other risk factors like diabetes. It occurs anywhere from a few months to several years after the initial operation.
Treating the Secondary Opacification
Fortunately, the clouding caused by PCO is treated with a simple, non-invasive procedure. The treatment is called a YAG laser capsulotomy, utilizing a specialized laser to create a small, clear opening in the center of the clouded posterior capsule. This opening is made directly behind the clear artificial lens, instantly restoring a clear path for light to reach the retina.
The procedure is performed on an outpatient basis and typically takes only a few minutes. The eye is numbed with drops, and no surgical incisions are required. The laser energy precisely vaporizes the cloudy tissue, and the patient may notice an immediate improvement in vision, although some temporary floaters are common as the debris settles. This treatment is generally a permanent solution because once the central tissue is cleared, the cells have no surface to grow back onto in the visual axis.