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What is posterior capsular opacification (PCO)?

posterior capsular opacification

What is PCO?

Posterior capsular opacification (PCO) is the clouding of the posterior lens capsule in which an IOL is implanted. It is the most common complication of cataract surgery. About one in five people develop PCO within one year after cataract surgery. About one-third develop PCO after five years. 

How is a PCO different from a cataract?

A cataract is the clouding of the natural lens

A cataract occurs when the natural lens of the eye becomes cloudy. When the cataract begins to interfere with activities of daily life, cataract surgery is performed.

During cataract surgery, the hazy, natural lens is removed and a clear, artificial lens called an intraocular lens (IOL) is implanted. This IOL is placed inside the lens capsule that held the original, natural lens.  

A PCO is the clouding of the posterior lens capsule surrounding the IOL

After cataract surgery, it is not possible to develop another cataract. This is because the IOL is made of an artificial, synthetic material. 

Months to years after cataract surgery, a cloudy membrane will sometimes form in the posterior (back) part of the lens capsule that holds the IOL. This is the result of lens cells left behind in the lens capsule after the surgery. 

What are the symptoms of PCO?

The symptoms of PCO and cataracts are similar. This is because both conditions make it difficult for light to pass through the lens to the retina.

Some of these symptoms include:

Why is PCO called a "secondary cataract"?

Although this condition is sometimes called a "secondary cataract," it is not a cataract. 

The IOL has not become cloudy. The capsule that surrounds the IOL has become cloudy.

It can be distressing to experience symptoms so similar to cataracts after cataract surgery.

This is why it is important to understand that PCO is not actually the return of a cataract. PCO can be treated during a brief visit to your doctor’s office. It does not require additional cataract surgery.

What is the treatment for PCO?

PCO usually develops slowly, much like a cataract. If the decrease in vision starts affecting your daily life, your eye doctor may recommend a procedure called YAG laser capsulotomy.

This procedure directs a laser beam at the posterior part of the lens capsule that cuts away the cloudy tissue, restoring clear vision. The procedure requires eye dilation, but it does not require an incision and is brief and painless. 

After a few hours of observation to ensure that your eye’s pressure is normal and stable, you will be able to go home. You may notice some floaters for a few days after the procedure, but they will decrease over time.

The risks of this procedure are low. Although complications are uncommon, they can include: 

How do I know if I need treatment for PCO?

PCO usually develops slowly, much like a cataract. If your vision begins to decrease after cataract surgery, let your doctor know. Your cataract surgeon can determine if YAG laser capsulotomy is the appropriate treatment for you.

Posterior capsule opacification. Experimental Eye Research. February 2009.

A systematic overview of the incidence of posterior capsule opacification. Ophthalmology. July 1998.

Posterior capsular opacification: A problem reduced but not yet eradicated. Archives of Ophthalmology. April 2009.

An overview of Nd:YAG laser capsulotomy. Medical Hypothesis Discovery and Innovation in Ophthalmology. June 2014.

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