Posterior Capsule Opacification, AKA “Secondary Cataract”

Posterior Capsule Opacification – “Secondary Cataract”

Cataract surgery is a common procedure done to improve vision for most people. While the procedure is generally safe, it is normal for some patients to develop complications. At first, patients can experience blurry vision a few days after cataract removal. During this period, the eyes heal and adjust to the artificial lens inserted during cataract surgery.

However, if your vision starts becoming cloudy several months or years after the surgery, chances are posterior capsule opacification is to blame.

What is Posterior Capsule Opacification?

Also known as secondary cataracts, posterior capsule opacification is a common post-op complication of cataract surgeries. Ophthalmologists remove and replace the natural clouded lens with an artificial lens during the surgery. The eye surgeon should ensure that the integrity of the lens capsule, a transparent membrane supporting the lens, isn’t affected.

The lens capsule remains intact in most patients after the surgery. However, some patients develop posterior capsule opacification, where there is residual growth of epithelial cells on the back of the lens capsule. Such cellular growth opacifies the capsule and makes it hazy. This prevents light from traveling through the central visual axis of the eye.

Signs and Symptoms of Posterior Capsule Opacification

The symptoms of posterior capsule opacification resemble those of cataracts. These symptoms occur months or years after cataract extraction. They include:

  • Decreased vision
  • Blurred vision
  • Increasing light sensitivity
  • Halos around light
  • Difficulty reading
  • Impaired contrast sensitivity
  • Double vision

If PCO affects the visual axis, patients present with the following signs:

  • Elschnig’s pearls – this is common in pearl-type posterior capsule opacification. Here, clusters of lens epithelial cells present as clear, round pearls that retro-illuminate. They can decrease your visual acuity if they collect along the visual axis.
  • Soemmerring rings – here, rings composed of cortical fibers and residual lens epithelial cells form between the edge of the remaining anterior capsule and posterior capsule. In most cases, the rings are too peripheral and cannot cause significant visual symptoms. However, severe accumulation can cause glare and loss of vision.
  • Capsular wrinkling – as mentioned, capsular opacification forms from the remaining viable lens epithelial cells after the removal of the cortex and nucleus during cataract surgery. Capsular contraction or wrinkling of the capsule is exacerbated by metaplasia and the conversion of lens epithelial cells into myofibroblasts.

Epidemiology and Risk Factors

Posterior capsule opacification (PCO) occurs in between 20 and 50% of cataract surgery patients within five years after the procedure. While PCO incidence has declined recently, no definitive proof can verify the decline. Also, these could be cases of later onset. Generally, young patients, particularly infants and children, have high incidence rates of developing PCO.

Some risk factors of posterior capsule opacification include:

  • Previous history of intraocular inflammation
  • The age of the patient
  • Small-sized capsulorhexis
  • Poorly done intraoperative cortical cleaning
  • Pseudoexfoliation syndrome
  • Capsular fixation of lens implant
  • Design of lens implant
  • Modification of lens surface
  • Intraocular silicone oil

Conditions such as uveitis, diabetes, retinitis pigmentosa, and myotonic dystrophy

Diagnosis and Treatment of Posterior Capsule Opacification

Diminished visual acuity and the development of blurry vision in patients who have undergone cataract surgery should prompt your ophthalmologist to suspect PCO. Clinical diagnosis of PCO is based on patient history and slit-lamp eye examination. Severe posterior capsule opacification enough to cause visual disturbance in teens and old adults is treated with YAG laser capsulotomy.

PCO is rarely treated with surgical capsulotomy. Laser capsulotomy is a painless procedure that treats PCO by penetrating the cloudy capsular tissue. The resultant opening restores vision by allowing light beams to travel through the eye.

Laser treatment takes a maximum of five minutes. Like other procedures, your ophthalmologist will start by numbing the eye for comfort before performing the procedure. Most patients require laser treatment only once. Recovering from the procedure is manageable, as it has minimal post-op discomfort. You can also resume normal activity, and vision improves within 24 hours.

Young children who cannot undergo YAG capsulotomy can be treated with capsulectomy or pars plana vitrectomy. More immunological and pharmacological PCO treatment remedies are currently being investigated.

Complications of YAG Laser Capsulotomy

Even though YAG laser capsulotomy is non-invasive and quick, it has a few risks. Besides, this procedure is not available in most developing countries. Complications following capsulotomy are minimal but include:

  • Retinal detachment
  • Cystoid macular edema
  • IOL damage
  • Iris hemorrhage
  • Iritis
  • Corneal endothelial cell loss
  • Exacerbated endophthalmitis
  • Increased intraocular pressure
  • Corneal edema

Though rare, patients can develop re-opacification, necessitating another laser treatment.


While YAG capsulotomy can treat PCO effectively, the cost and potential complications of this treatment make PCO prevention important. Several studies have attempted various interventions that can delay or prevent the formation of lens epithelial cells. These preventive measures include better pharmacological options and intraocular lens design and material.

Like actual cataracts, posterior capsule opacification can cause progressive vision loss. If cloudy vision starts affecting your daily activities, you should seek medical assistance from your ophthalmologist.

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