Posterior capsule opacification

A cataract is a clouding of the lens in your eye. It normally occurs as part of the ageing process. There are other reasons why a cataract can develop earlier in life. These include some medications, other eye or health conditions, or trauma to the eye.

During cataract surgery the natural lens of your eye is replaced by a clear artificial lens. This new artificial lens is placed inside your lens capsule, the thin membrane that covers the natural lens of the eye. The lens capsule supports the artificial lens and is normally clear allowing light to enter the eye.

PCO occurs when cells remaining after cataract surgery grow over the back (posterior) of the capsule. This causes it to thicken and become slightly opaque (cloudy). This means that light is less able to travel clearly through to the retina at the back of your eye. As a result, your sight can become blurred and cloudy, or you may have problems with bright lights and glare. The cells usually grow over the capsule slowly so the changes to your sight happen gradually. PCO usually occurs months or years after surgery. In a few people, it can happen early on after cataract surgery (within a few weeks).

The way PCO affects your sight is very similar to the way that cataracts affect sight. If you have had cataract surgery in both eyes, PCO can affect both eyes, but each eye may be affected by different amounts or at different times.

PCO is quite common. Around 20 in 100 eyes (about 1 in 5) develop it within 3 years of cataract surgery, and about 34 in 100 eyes (around 1 in 3) within 5 years.

There are some reasons why you may be more likely to develop it. Factors which can increase the risk of PCO developing include:

• Presence of other eye conditions such as diabetes related eye conditions, glaucoma, retinitis pigmentosa or high short sightedness (high myopia).
• Being of a younger age at the time of cataract surgery.
• Complications during or after cataract surgery, for example, if there has been inflammation (swelling) in your eye.

However, it’s not unusual to develop PCO even if you don’t have these risk factors.

PCO can be detected by an optometrist (optician) when they examine your eyes during an eye test. Using a bright light, they will be able to see the cells clouding the posterior capsule. If PCO is causing symptoms and impacting your vision, your optometrist can refer you to the eye hospital for YAG laser treatment. YAG laser treatment for PCO is a very common procedure available on the NHS.

PCO is treated by a very low risk, quick, painless laser treatment. The laser that is used is a very low energy laser called a “Nd: YAG laser”. This is sometimes referred to as just “YAG”. The Nd: YAG laser is a special sort of light that can cut the lens capsule delicately without any risk of damage to other parts of your eye.

It is carried out in the outpatient clinic. If you have PCO in both eyes, then it is possible to have treatment for both on the same day.

At the appointment you will be given some eye drops to dilate (widen) your pupil. These can make your vision blurrier for a while. Sometimes, but not always, a special contact lens is used. This is to help to keep your eye in the right position and help with focusing the laser. If this is needed, you will be given eye drops to numb) the front of your eye so that you do not feel any discomfort. However, you will usually be aware that the contact lens is touching the eye.

Once your pupil is dilated, you will be asked to sit and place your head on the headrest of the laser machine. This will help to keep your head and eye still while the treatment is carried out.

The laser is focused exactly onto the back of the lens capsule. A small circle-shaped area is cut away to allow light to pass through the capsule to the retina. Some of the capsule is left behind to keep your artificial lens in place (like a cuff around the artificial lens). The laser removes enough to allow the light to travel to the retina.

The laser uses a wavelength of light that cannot be seen. However, you may notice a red light, which helps focus the laser beam. Each laser pulse is over in a fraction of a second. You will not feel any pain or discomfort. You may notice a few flashing lights or hear some faint clicks coming from the machine as the laser works. The procedure does not take very long. Normally it will take about 5-10 minutes.

The laser treatment is considered very safe. All procedures carry some risk. However, serious side effects from laser treatment for PCO are rare.

Your eye may be a little sore after treatment if a contact lens was used to steady your eye. This should soon feel better.

For some people, laser treatment for PCO can cause eye pressure to rise. This can be an issue if you already have glaucoma. This is because your eye pressure may already be higher than normal. If there is concern about this, your eye pressure will be checked soon after the laser treatment. If your eye pressure has increased, you will be given some eye drops or a tablet to bring it back down.

Very rarely, laser can cause a retinal detachment. This can happen days, weeks, months or years after the treatment. This is more likely to happen if you are very short sighted.

If it does occur, retinal detachment can be treated with surgery to re-attach the retina.

It’s important to have your eyes checked immediately if you experience the following symptoms, as these may be a sign of a retinal detachment:

• a sudden onset of new floaters (other than those immediately after laser treatment)
• flashing lights
• a dark curtain moving up, down or across your vision.
• blurred vision

It is important to stress that these risks are rare complications of the laser treatment. Most people get an excellent and permanent improvement in their vision following laser without experiencing any issues. If you notice any unusual symptoms following your laser treatment, contact your eye clinic for advice.

It may take a few days for your sight to become clear again. You may notice “floaters” immediately after your laser treatment. This is common. Floaters are harmless clumps of cells which move around inside the clear vitreous gel which fills the inside of the eye. You may see floaters as dots, circles, lines, clouds, or cobwebs. Over time these will settle down and become less noticeable.

The laser treatment does not require any incisions or stitches. You are normally able to return to your daily activities straight away. However, your pupils will still be dilated immediately after treatment. This means your vision may be blurred for a few hours afterwards. You will need to avoid driving until this blurriness has gone.

You should not drive yourself home after the treatment as it can take some time for the drops that dilate your pupils to wear off, and your vision may still be blurry following the laser treatment.

You should arrange to get home by public transport or arrange for someone else to drive you home following your treatment.

After laser treatment for PCO, your sight should go back to the way it was following your original cataract surgery. This is as long as there are no other eye conditions or problems affecting your sight. You will still need to use any glasses you used before the PCO developed.

Your optometrist may have advised against updating your glasses when they referred you for PCO treatment. . If this is the case, you may need to return to your optometrist to have your eyes tested again before getting new glasses. However, the glasses prescribed after your cataract surgery should usually work well again after the YAG laser treatment.

You will generally only need to have laser treatment for PCO once. This is because the laser removes the central tissue of the capsule on which the cells develop. Very rarely, cells may develop around the opening of the capsule. Sometimes, the opening in the capsule made by the initial laser treatment can shrink. This can affect the vision in your line of sight. These changes can cause PCO to return. It is possible to have further laser treatment if it’s needed.

It is possible for your PCO to progress while you are waiting for your treatment. This can cause your vision to become blurrier over time. PCO can generally progress over weeks or months. How much it may affect your vision can vary from person to person. Some people may notice a reduction in their vision over weeks. For others, it may take months or even longer.

Waiting for treatment won't impact how successful your treatment will be. A delay in being treated doesn't mean that it will be less successful or cause other problems in your eye. Treatment can be successful when given at any stage of PCO development. However, coping with reduced vision in the meantime can be difficult, especially if both eyes are affected. Sometimes making things bigger, brighter and bolder can make things easier to see in the short term while you are waiting for treatment. YAG laser treatment is available privately as well as on the NHS.

PCO can cause your vision to become blurry and you may have glare or difficulties in bright light before you have the laser treatment. You may also find reading difficult. There are a lot of things you can do to make the most of your vision if you are having any difficulties while you wait for treatment. This may mean making things bigger, using brighter lighting, or using colour to make things easier to see.

Find out more about how to make the most of your sight by downloading our booklet: