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Cataract Surgery Complications

Cataract surgery complications are few, and cataract surgery is among the most common and most successful surgical procedures performed today.

According to the American Society of Cataract and Refractive Surgery (ASCRS), 3 million Americans undergo cataract surgery each year, with an overall success rate of 98 percent or higher.*


Also, a study of more than 200,000 Medicare beneficiaries who underwent cataract surgery between 1994 and 2006 found that 99.5 percent of patients had no severe postoperative complications and the risk of severe complications has decreased with advances in surgical tools and techniques.**

Potential cataract surgery complications include:

  • Posterior capsule opacity (PCO)
  • Intraocular lens dislocation
  • Eye inflammation
  • Light sensitivity
  • Photopsia (perceived flashes of light)
  • Macular edema (swelling of the central retina)
  • Ptosis (droopy eyelid)
  • Ocular hypertension (elevated eye pressure)

When cataract surgery complications do occur, most are minor and can be successfully treated medically or with additional surgery.

Posterior Capsule Opacity - A Common Cataract Surgery Complication

One of the most common cataract surgery complications is a posterior capsule opacity (also called posterior capsule opacification or PCO).

Posterior capsule opacity or PCO. The PCO has been removed with a YAG laser.
A procedure called a YAG laser capsulotomy can quickly restore vision following posterior capsular opacification.

Although some people call PCO a "secondary cataract," it really is not a cataract. Once a cataract is removed, it does not come back.

During cataract surgery, your surgeon will remove the cloudy natural lens of your eye (cataract) and replace it with an intraocular lens (IOL). Much of the thin clear membrane that surrounds the natural lens (called the lens capsule) is left intact during surgery and the IOL usually is implanted within it.

When the cataract is removed, your surgeon makes every attempt to maintain the integrity of the lens capsule, and normally your vision after cataract surgery should be very clear.

However, in about 20 percent of patients, the posterior portion of the capsule becomes hazy some time during cataract surgery recovery or even months later, causing PCO. Posterior capsule opacification occurs because lens epithelial cells remaining after cataract surgery have grown on the capsule.

In some cases, if the condition progresses significantly, your vision may be worse than it was before cataract surgery.

Treating Posterior Capsule Opacity

Fortunately, a YAG laser can treat posterior capsule opacity safely, effectively and painlessly. This procedure, known as YAG laser capsulotomy, often can be performed in your doctor's office.

YAG laser capsulotomy involves just a few simple steps:

  • Usually the eye is dilated before the procedure, with dilating eye drops.
  • A laser removes the hazy posterior capsule from your line of sight without making an incision or "touching" the eye.
  • Many ophthalmologists recommend anti-inflammatory eye drops following the procedure.
Yag laser procedure.
This drawing shows a YAG laser capsulotomy, where the hazy posterior capsule is removed from your line of sight, making vision clear again.
A laser capsulotomy is a relatively simple, in-office procedure that takes only a few minutes. A laser beam is directed at the cloudy capsule behind the intraocular lens (IOL) and the energy from the laser vaporizes the tissue, restoring clear vision.

The procedure takes only a few minutes and is entirely painless; nor does discomfort occur post-operatively.

You must remain still during the procedure, however. Very uncooperative patients, such as children and mentally disabled people, may require sedation.

Following a YAG laser capsulotomy, you may resume normal activities immediately. You may experience some floaters afterward. These will likely resolve within a few weeks.

Most people can expect their vision to improve within a day. As with any eye procedure, however, call your eye doctor immediately if vision worsens or fails to improve.

Because the YAG laser removes the central zone of the cloudy posterior capsule behind the intraocular lens, the condition cannot return. So only one laser treatment is required to permanently eliminate vision loss caused by posterior capsule opacification after cataract surgery.

YAG Laser Capsulotomy Risks

Although a YAG laser capsulotomy poses slight additional risk, overall the procedure is extremely safe. The most important risk is that the retina can become detached from the inner back of the eye.

Statistics suggest that the lifetime risk of a detached retina as a cataract surgery complication in the United States is about 1 percent. That number rises to about 2 percent after YAG laser capsulotomy. It is important to be aware of this cataract surgery risk.

Dislocated Intraocular Lenses

Another example of cataract surgery complications is malpositioned or dislocated intraocular lenses. You may see the edge of the lens implant, or you may even develop double vision. If the intraocular lens becomes too badly dislocated, your visual acuity could decrease substantially.

How can an IOL become malpositioned or dislocated?

In most cataract surgeries, the intraocular lens is placed inside the "capsular bag," which contains the cloudy natural lens or cataract of the eye.

Special Alert For Men

If you are taking prostate drugs (tamsulosin) such as Flomax to improve urine flow, you are at risk for a cataract surgery complication called intraoperative floppy iris syndrome (IFIS). Higher rates of detached retinas during cataract surgery also have been associated with these drugs.

These alpha-blockers relax prostate muscles to help the bladder empty. But they also can affect muscles in the colored part of the eye (iris). During cataract surgery, the eye's pupil can suddenly constrict — hindering a surgeon's ability to successfully complete the operation. This can cause possible complications.

Ophthalmologists make every attempt to maintain the integrity of the capsular bag so that the intraocular lens can be positioned correctly within it. But the capsular bag is extremely thin — approximately the thickness of a single red blood cell — and can sometimes rupture or break.

Also, the capsular bag itself may dislocate due to weakness or breakage of the fibers (zonules) that hold it in place, resulting in a condition known as zonular dialysis. This condition places you at risk of malpositioning or dislocation of the lens implant.

Even without underlying complications, intraocular lenses can still dislocate — especially if one of the springy "arms" holding the lens in place is positioned improperly inside the capsular bag or becomes malpositioned later on.

When an intraocular lens implant is malpositioned or dislocated, your cataract surgeon can probably reposition it in a second procedure. In some cases, the lens implant must be sewn in place, or another type of lens must be implanted.

If IOL dislocation occurs following a recent cataract surgery, repositioning the lens should be done soon. This is because lens implants begin to "scar" into place approximately three months after original implantation and can become much more difficult to remove.

If you do experience a malpositioned or dislocated intraocular implant, your chances of a good outcome following a second procedure are very good if you and your surgeon take action promptly.

Also, a recent Mayo Clinic study of more than 14,000 cataract surgeries performed between January 1980 and May 2009 found that the risk of late IOL dislocation after cataract surgery was very low: At 10 years after surgery, the cumulative risk was 0.1 percent; at 20 years, it was 0.7 percent; and at 25 years, it was 1.7 percent.

Other Cataract Surgery Complications

Other potential cataract surgery complications range from minor eye inflammation to devastating vision loss. The risk of severe vision loss is very rare and may occur as a result of infection or bleeding inside the eye.

Some cataract surgery complications occur quite a while later. For example, a detached retina can occur months or years after a perfectly successful cataract procedure.

Most patients with retinal detachment have a good outcome if they see their ophthalmologist when symptoms first begin and treatment is done immediately. However, a small percentage will have substantially and permanently reduced vision.

Be sure to report floaters, flashes of light and a curtain-like vision loss to your ophthalmologist immediately, as these symptoms may indicate a retinal detachment has occurred.

Other potential cataract surgery complications are minor and may include:

Minor complications usually clear up with medications and more healing time.

Vision After Cataract Surgery

According to ASCRS, studies show that 95 percent of patients who choose a standard IOL for cataract surgery have their vision fully restored to its pre-cataract state, and if you choose a premium IOL your vision may be even better than it was before.*

If you have any problem with sensitivity to sunlight after cataract surgery, eyeglasses with photochromic lenses, which darken automatically to UV rays, often can provide relief. Also, for residual refractive error and presbyopia after surgery, progressive lenses with anti-reflective coating often can sharpen your vision for activities like night driving and reading.

People whose vision fails to improve after cataract surgery often have underlying eye disorders, such as age-related macular degeneration, diabetic retinopathy and other eye conditions. Some of these individuals may benefit from other procedures or from low vision aids.

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Page updated August 2017


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