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Posterior Capsular Opacification: A Complication of Cataract Surgery

Posterior capsular opacification affects around 50 percent of patients who have had cataract surgery. If left untreated, it could lead to impaired vision and even blindness. 

The good news is that while PCO can be a bothersome condition, it can be effectively treated.

What Is PCO?

Posterior capsular opacification (PCO), also known as a secondary cataract, is a complication of cataract surgery. 

Naturally, your eye’s lens is clear, but after a cataract forms, it becomes cloudy, causing vision to be impaired. The natural lens is removed with cataract surgery, but the posterior capsule remains to keep the artificial lens in place.

PCO occurs when cells in the posterior capsule cluster and multiply, causing cloudiness and impairment in vision.

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What Exactly Causes PCO?

Posterior capsular opacification, or PCO, is a condition where the crystalline lens capsule becomes cloudy and opaque. It is one of the most common complications of cataract surgery.

When a person has cataract surgery, they have their natural lens removed and replaced with an artificial intraocular lens (IOL). The IOL is designed to correct vision problems caused by cataracts and help patients see clearly again. Unfortunately, many factors can cause PCO after cataract surgery.

The main reason why PCO occurs after cataract surgery is that cells that remain over the back of your capsule can grow together to form a membrane. This causes the capsule to thicken and become slightly opaque (cloudy), which decreases light transmission.

These deposits can reduce vision quality and make it harder for you to see clearly at night or in low-light conditions. It can also increase glare from bright lights like sunlight or street lamps while driving.

The condition can occur at any point after cataract surgery, but it most often happens within three months of the procedure.

What Are the Symptoms of PCO?

The symptoms of posterior capsular opacification are usually mild and include the following:

  • Difficulty recognizing colors
  • Sensitivity to lights
  • Blurry vision, especially when driving at night or in low-light conditions
  • Cloudy spots in your vision, especially when looking at lights
  • Double vision
  • Inability to focus

If you experience these symptoms after undergoing cataract surgery, consult your ophthalmologist immediately.

How Common Is PCO?

The American Academy of Ophthalmology estimates that over 1 million people undergo cataract surgery annually in the United States. It’s a safe and effective procedure for restoring vision for many people with impaired eyesight. However, it does have risks, one of which is PCO.

Some studies show that posterior capsular opacification occurs in up to 20 to 50 percent of patients who have had cataract surgery within two to five years following surgery.

Risk Factors

While it is not uncommon for PCO to develop after cataract surgery, some risk factors can make it more likely to occur. These include the following:

Younger age is a significant risk factor for PCO. However, all individuals who have undergone cataract surgery are at risk for developing this condition.

How Is PCO Diagnosed?

Diagnosing PCO requires a physical examination by an eye doctor or ophthalmologist. The doctor will examine your eyes with a slit lamp, which provides very bright illumination that helps them see more detail than they would with regular lighting. 

They will look for cloudiness on the back surface of your eye’s lens and check for any signs of infection around your eye.

How Is Posterior Capsule Opacification Treated?

Posterior capsular opacification can be treated with laser ablation, where an ophthalmologist uses a yttrium aluminum garnet laser to remove the cloudy material in your lens capsule. 

A posterior capsulotomy is a procedure performed on an outpatient basis that takes less than 15 minutes to complete. When both eyes are affected by PCO, it is possible to treat them on the same day. 

The procedure is quick, safe, and effective. You’ll be able to see clearly again shortly following the surgery.

Results to Expect After Posterior Capsulotomy

While it’s impossible to predict exactly how your vision will improve after a posterior capsulotomy, most people can expect to see an improvement in their near vision.

Most patients will experience an immediate improvement in their vision following treatment. However, the extent of that improvement and how quickly it occurs depend on the severity of cataracts and your overall eye health.

Some patients may experience mild eye pain or irritation for several days after the procedure, but this typically resolves within a few days.

If you are experiencing any discomfort or blurry vision after surgery, you should contact your doctor immediately.

How to Prevent PCO

Although Nd: YAG laser capsulotomy can effectively treat PCO, the procedure is expensive and comes with a risk of complications.

Many studies have attempted to identify interventions that delay or inhibit the formation of PCO. These interventions include the following

IOL Design & Material

The square, truncated optic edge IOL design has shown to have a decreased risk for posterior capsule opacity (PCO) compared to the soft round IOL design.

Scientists believe that the mechanical barrier provided by the optic edge prevents LEC growth over the posterior capsule. Research has not yet determined whether the design of individual loops in IOLs affects the development of PCO.

Surgical Techniques 

Several surgical techniques have been studied to reduce the frequency of PCO, including these:

  • Hydrodissection-enhanced cortical clean-up
  • Broad adhesion of the IOL to the posterior capsule
  • Cortical cleanup with aspiration, irrigation, and polishing of the capsule
  • In-the-bag capsular fixation of the optic and haptic

Pharmacological Approaches 

Researchers are trying to develop drugs that can affect the regeneration of remaining LECs without harming other tissues in the eye.

Anti-inflammatories, antimetabolites, immunological agents, and hypo-osmolar drugs are some of the drugs used.

Can PCO Come Back?

If you’re diagnosed with PCO, your ophthalmologist will likely recommend having it treated with YAG laser surgery. This procedure has been proven effective in permanently correcting vision problems caused by PCO and should last a lifetime after treatment has been completed successfully. 

When to See a Doctor

If you notice any changes in your vision after cataract surgery, it’s important to see your doctor as soon as possible. Posterior capsular opacification can be treated with either non-surgical or surgical methods, but the earlier it’s found, the easier it will be for your doctor to treat it.


  1. Factors Affecting Posterior Capsule Opacification in the Development of Intraocular Lens Materials. (June 2021). Pharmaceutics.

  2. Posterior Capsule Opacification. (January 2022). American Academy of Ophthalmology.

  3. IOL Implants: Lens Replacement After Cataracts. (April 2021). American Academy of Ophthalmology.

  4. Cataract Surgery: Risks, Recovery, Costs. (July 2022). American Academy of Ophthalmology.

  5. Myotonic Dystrophy (DM). The Muscular Dystrophy Association.

  6. Retinitis Pigmentosa. (March 2022). National Eye Institute.

  7. What Is Uveitis? (November 2021). National Eye Institute

  8. What Is a Posterior Capsulotomy? (September 2022). American Academy of Ophthalmology.

  9. Comparison of Different IOLs in Secondary Cataract Assessment. (March 2012). Investigative Ophthalmology & Visual Science.

Last Updated January 10, 2023

Note: This page should not serve as a substitute for professional medical advice from a doctor or specialist. Please review our about page for more information.

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