Posterior Capsule Opacification, Why Vision Can Turn Hazy After Cataract Surgery

The operation went well and the world looked bright again. Then, some months or years later, the haze starts to creep back. Reading gets harder, and the old blur seems to have returned. Many people assume that the cataract has grown back. In most cases it has not. The usual cause is a different problem, called posterior capsule opacification, or PCO. It is not unusual, and it has a simple treatment. This guide explains what PCO is, why it happens after cataract surgery and what the laser treatment involves.

What the lens capsule is

To understand PCO, it helps to picture how a cataract operation works. The natural lens of the eye has become cloudy, so the surgeon removes it. In its place goes a clear artificial lens, called an intraocular lens or IOL. A short guide to cataract surgery in Karachi describes the operation in more detail.

The new lens does not float loose inside the eye. It sits inside a thin, clear membrane called the lens capsule. The Academy suggests thinking of the back part of the capsule, the posterior capsule, as a transparent pocket. It holds the artificial lens in place, and it once held the natural lens that became the cataract.

PCO happens when that pocket becomes cloudy. The American Academy of Ophthalmology says that the capsule can turn cloudy or wrinkled weeks, months or years after surgery, and that this causes blurry vision.

A reminder of what happened in the operation

It helps to remember how the operation went. The Academy describes cataract surgery as an outpatient procedure in most cases. The eye is numbed with drops or with an injection around the eye, and the patient is awake. The surgeon makes tiny cuts near the edge of the cornea and uses very small instruments to break up the cataract and remove it. Then the new lens is put into place.

The cuts usually do not need stitches, because they are self-sealing and close by themselves over time. After about 15 to 30 minutes in a recovery area, most patients are ready to go home. What stays behind in the eye is the capsule. It holds the new lens, and it is the part that can cloud later.

A cataract does not come back

The confusion starts with the names. PCO is sometimes called a secondary cataract, and sometimes scar tissue. Neither name is quite right.

The Academy states that cataracts do not return once the natural lens has been removed. PCO is not a cataract, although it can cause similar blurry vision. The scar tissue label is also loose. The Academy explains that PCO is not like a scar on the skin. People call it a scar only because it appears after the eye has healed from the operation.

This matters because it changes what people expect. PCO is treated with a laser, not with a second cataract operation. The artificial lens stays where it is, and the cloudy membrane behind it is the part that gets attention.

How soon it appears and how it feels

There is no fixed timetable. The Academy says vision can become cloudy or blurry weeks, months or years after cataract surgery, and that this is not unusual.

The effect is a return of blurry vision. The page on posterior capsulotomy describes it as vision that becomes cloudy again. A window that has misted over is one way to picture it.

Other reasons vision can blur after surgery

Not every blur after a cataract operation is PCO. The Academy points out that cataract surgery will not restore vision lost to other eye conditions, such as macular degeneration, glaucoma or diabetic retinopathy. A person with one of these conditions can have a perfectly clear lens and still see poorly.

The Academy also says that, after the laser treatment for PCO, sight should improve in about 48 hours if there are no other eye problems affecting vision. The wording is a reminder that some people have more than one thing going on.

The practical lesson is simple. Do not decide for yourself what is causing the haze. An examination can tell the two apart. If the doctor widens your pupils to look at the back of the eye, a guide to what a dilated eye exam checks explains what the doctor is looking at.

The treatment, a quick laser

When PCO is confirmed and is affecting vision, the treatment is a laser procedure. Its names are posterior capsulotomy and YAG laser capsulotomy. The laser makes a small opening in the cloudy capsule. Light can then pass through again, and vision clears. The Academy describes PCO as easily treated in this way.

The procedure is typically done by an ophthalmologist, in the office or in an outpatient surgery centre. It takes about five minutes. The Academy describes the steps.

• The eye may be numbed with drops. Other drops may be used to widen the pupil.
• The doctor points a special laser at the back of the lens capsule and makes a small opening.
• Once your vision is clear again, you can usually go back to your normal daily activities. You may need someone to drive you home. The doctor will tell you if there is anything you should not do straight afterwards.
• You may need to use eye drop medicine for a few days. The doctor will say whether that is necessary.

It is a short procedure, but it is still a procedure on the eye, so the instructions on the day should be followed carefully.

How soon after cataract surgery it can be done

Patients sometimes ask whether the laser can be done soon after the cataract operation. An ophthalmologist answering questions for the Academy says it can be done early, but most ophthalmologists think it wiser to wait 30 to 60 days. That gives the artificial lens time to settle fully inside the capsule, and it avoids adding any swelling right after the operation. The surgeon who knows your eye can give a more specific answer.

Can it happen again

The Academy says that a posterior capsulotomy typically needs to be done only once per eye. An ophthalmologist answering questions for the Academy adds that it can be done more than once in the same eye, but that once is usually enough. One reason for a repeat is that the first opening was not large enough, so the doctor wants to enlarge it.

Risks worth knowing about

All eye procedures carry some risk, and the Academy lists the possible ones for this laser treatment.

• A detached retina. The tissue at the back of the eye can lift away.
• A rise in eye pressure.
• Movement of the artificial lens. It might shift through the new opening in the capsule.
• Swelling in the eye. Steroid eye drops may be needed.

The detached retina deserves special attention. The Academy says that if it happens, you may see what looks like a grey or black curtain moving across your field of vision. You might also see many floaters or flashes of light. Call your ophthalmologist immediately if this happens. Do not wait to see whether it settles.

Planning the day of the laser

A few simple steps make the visit easier.

• Ask a family member to come with you, because you may need someone to take you home.
• Bring the list of your medicines and the drops you already use. If drops are prescribed after the laser, putting in eye drops safely is a skill worth practising.
• Ask before you leave what you may do the same day and what you should avoid.
• Note the warning signs, and ask which number to call if they appear.

Words you may hear at the clinic

The names around this condition can sound more serious than the problem is. Here is what the common ones mean.

• Intraocular lens, or IOL. The clear artificial lens placed in the eye during cataract surgery.
• Lens capsule or posterior capsule. The clear pocket that holds the lens in place.
• Opacification. A plain word for becoming cloudy. Posterior capsule opacification means clouding of the back of the capsule.
• Secondary cataract or scar tissue. Other names for the same problem, although it is not a true cataract.
• Posterior capsulotomy or YAG laser capsulotomy. The laser treatment that makes an opening in the cloudy capsule. YAG is the type of laser.

Questions to ask your surgeon

• Is the haze I describe caused by PCO, or by something else?
• Is the laser needed now, or can it wait and be watched for a while?
• What are the risks in my particular eye?
• Will I need drops afterwards, and for how long?
• If my sight does not improve within two days, whom should I contact?

If your sight has gone hazy

If your vision has turned hazy after a cataract operation, book an eye examination rather than waiting. For general questions about hazy vision after cataract surgery, ask PEBS about posterior capsule opacification. Anyone who would like to give can review ways to support patient care.

A cloudy capsule is a treatable reason for blurred sight, but only an examination can say that it is the reason in your case.

This article is general information and does not replace an examination by an eye doctor.