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Cataracts: Cataract surgery

Last Update: October 10, 2019; Next update: 2022.

A cataract is an eye condition where the lens of the eye gradually becomes cloudy – usually as part of the natural aging process. The only effective treatment option is surgery. Cataract surgery involves removing the cloudy lens and replacing it with a new, artificial lens.

Cataracts cause vision loss. Your eyesight becomes increasingly dull and blurry, as if you were looking at things through a veil or fog, and you become more sensitive to light and glare. If cataracts are left untreated, they can – but don't always – lead to blindness. Some people’s vision is only slightly affected, whereas others might lose their eyesight very quickly.

Surgery involves removing the cloudy lens and replacing it with an artificial lens. It is one of the most common surgical procedures performed in Germany, where about 700,000 people have cataract surgery each year.

Are there alternatives to surgery?

Some people try to make up for their vision loss using glasses or contact lenses at first. This can be effective for a while if the cataracts progress slowly and vision is only slightly impaired. But some people’s eyesight will already be severely affected or might get worse very quickly. There are no effective medications for the treatment of cataracts. Surgery is the only treatment that can improve vision in the long term.

When is it the right time for surgery?

Whether and when to have surgery is a personal decision. It will greatly depend on how much someone’s vision loss is affecting their independence and everyday activities. The following factors might play an important role: How good does my eyesight have to be for me to be able to do my job? Are there certain things that I can no longer do, such as reading and sports? Do I have problems finding my way around? Is it becoming too dangerous for me to drive a car?

As long as there are no symptoms, surgery isn't necessary – even if doctors find that the lens has become a little cloudy.

The stage of the disease usually has no influence on how well you can see after surgery, with the replacement lens. But surgery is more difficult if the cataract is very advanced. Eye tests are also no longer as accurate. So it's a good idea to have regular eye tests carried out by an eye doctor (an ophthalmologist). You can then talk to him or her about the right time for surgery.

Surgery is only performed on one eye at a time. If both eyes are affected by cataracts, one eye is operated after the other.

What else should I consider before surgery?

Another factor that's important for the decision is whether or not someone has other (eye) conditions that could influence the outcome of surgery. Some people also have glaucoma, age-related macular degeneration (AMD) or eye damage from diabetes. Then surgery often doesn’t lead to a noticeable improvement in vision.

Although most operations don't lead to complications, problems can arise. Your eye doctor should carefully inform you about the possible advantages and disadvantages of surgery before it is carried out. Because cataracts progress slowly and aren't an emergency, there's no need to rush into any decisions about whether or when to have surgery.

What does the surgery involve?

Cataract surgery involves removing the cloudy lens and replacing it with an artificial lens. At the beginning of the operation, a small cut is made at the edge of the cornea (the clear covering of the eye). Next, the membrane enclosing the lens is opened at the front. The inner core and outer cortex of the lens are then broken up into small pieces using ultrasound and sucked out through the small cut (phacoemulsification). Once the old lens has been removed in this way, an artificial lens is implanted. The artificial lens lasts a lifetime. Stitches are usually not needed at the end of the operation because the cuts are so small that they normally heal quickly on their own.

Some doctors offer laser surgery as an alternative. This procedure uses a laser to cut and reduce the size of the lens. It is not clear whether this has any health advantages over phacoemulsification.

The operation takes about 20 to 30 minutes. It is usually done as outpatient surgery, and you can be picked up a few hours after the procedure is completed.

It may be a good idea to have the surgery in a hospital if you need more intensive care, for instance because you have other medical conditions too.

What is the most appropriate type of anesthesia?

Cataract surgery can usually be done using only a local anesthetic, which is either injected close to the eye, or given in eye drops. Each method has its pros and cons: According to studies, people who have the injection experience less pain during surgery. Its effect may also still continue after surgery. But injections are associated with a greater risk of complications.

Pain was experienced during or after surgery by about

  • 36 out of 100 people who had eye drops, and
  • 13 out of 100 people who had an injection.

Anesthetic-related complications

  • are very rare when using eye drops: They occur in less than 1 out of 100 procedures.
  • But when an injection is used, about 7 out of 100 people experience swelling of the conjunctiva, or bruising or bleeding in the eye.

The type of anesthetic used probably doesn’t influence how good people’s eyesight is after surgery.

Anesthetic eye drops don't affect the eye muscles, so you can move your eyes during surgery. You will therefore be asked to look in one direction and keep your eyes still throughout the procedure. Because you need to be very calm and focused to do this, anesthetic eye drops aren't the right option for everyone, and are only considered for short operations.

How effective is surgery?

About 9 out of 10 people can see better after surgery than before: they have sharper vision with more contrast. Near- and far-sightedness improve, and you can see more in dim light. So surgery can improve your quality of life and make everyday activities easier. Many people are able to do things that were no longer possible, or were difficult, before they had cataract surgery – like driving a car, reading and working at a computer screen. But it can take a few weeks or months for your eyesight to improve as much as possible.

The artificial lens will usually last for a lifetime and won't wear out or become cloudy. This means that it probably won’t need to be replaced. But sometimes a secondary cataract (also known as posterior capsule opacity) develops. If the rear (posterior) lens capsule becomes cloudy in the months or years after the operation, it will cause your vision to worsen again. It is estimated that about 5 to 10 out of 100 people develop secondary cataracts within five years of initial cataract surgery. Secondary cataracts can be treated with a laser.

What are the possible complications?

Cataract surgery doesn't usually cause complications. But inflammations, injuries, bleeding and wound-healing problems are possible. This can lead to vision problems that need to be treated. The most common problems are listed below.

During surgery:

  • Damage to the lens capsule: in about 2 to 3 out of 100 people
  • Damage to the iris or eyeball: in less than 1 out of 100 people

After surgery:

  • Swelling of the retina: in about 2 to 3 out of 100 people
  • Lens dislocation (where the lens moves out of place): in about 1 out of 100 people
  • Retinal detachment: in about 1 out of 100 people
  • Inflammation inside the eye (endophthalmitis): in less than 1 out of 100 people

Some complications are more likely if the eye is numbed using an injection (see above). People who have other eye conditions have a higher risk of complications too.

Most complications don't have any long-term consequences, but they can lead to temporary problems such as impaired vision or slower wound healing. You might have to take medication for a while, or further eye surgery might be needed.

The most serious complication is an inflammation inside the eye. This happens when germs get into the inside of the eye, causing an infection. Symptoms include pain, swelling, a red eye and severe vision problems. If these kinds of symptoms occur in the days and weeks following surgery, it's important to go to an eye doctor immediately. Inflammation may lead to blindness or loss of the eye, so it needs to be treated with antibiotics as quickly as possible. Bleeding in the eye can cause serious problems too. But this happens in much less than 1 out of 100 people – this makes bleeding even less common than inflammations in the eye.

How do the various artificial lenses differ?

Artificial lenses are also known as intraocular lenses (IOLs). The following different types of lenses are available:

  • Monofocal lenses: This type of lens allows clear vision at one distance only. In other words, you have to decide beforehand what kind of monofocal lens you would like, depending on whether you would prefer sharper vision when looking at things that are far away, at medium range, or nearby. Wearing glasses can help compensate for the other ranges. For instance, if you choose a lens that allows you to see things that are far away clearly, you would need to wear glasses to read a book.
  • Multifocal lenses: These lenses allow clear vision both when looking at things that are far away and things that are nearby (like when reading a book). Then you might not need to wear glasses. But your vision might still be blurred when looking at objects at certain distances, and you would see somewhat less contrast than people who wear monofocal lenses. Glare is more of a problem with multifocal lenses too, for example when driving at night.
  • Toric lenses: This type of lens is especially suitable for people who have astigmatism.
  • Blue-light-blocking lenses: These lenses filter out blue light in an attempt to better protect the retina. But they weren't proven to have this effect in studies.
  • Extended-depth-of-focus (EDoF) lenses: Just like multifocals, these newer lenses allow clear vision both when looking at things that are far away and things that are nearby. But the clearer vision is only possible when looking at things that are at screen distance – you still need glasses to read books, for instance. They're less susceptible to glare than multifocal lenses are, though.

In Germany, statutory health insurers will only fully cover the costs of cataract surgery if a monofocal lens is implanted. Multifocal lenses, toric lenses, blue-light-blocking lenses and EDoF lenses are more expensive than monofocal lenses. Patients have to cover the difference in price themselves. Because using these types of lenses can be expensive, it's worth carefully considering the pros and cons of the different types of lenses before making a decision. It can be helpful to get a second opinion from a different eye doctor. Your health insurer can provide information about cost coverage.

Getting a well-fitting lens with the right strength (refractive power) is more important than the lens type. The eye doctor will do the necessary tests before the operation.

What do you need to pay attention to after the surgery?

An eye patch should be worn for one day after surgery. Your eye might itch or hurt a little, and it may feel like you have something in it. These problems usually go away again after a few days. The main thing to remember is to not rub or push against your eye if you have just had surgery. But it's alright to carefully touch the eye. You can return to most everyday activities as usual after a few days, apart from driving a car. It is best to talk to your eye doctor about whether or not to avoid certain activities at first. The doctor will also let you know when your eyesight is good enough for you to start driving again. This is usually possible after a few weeks.

Eye drops are prescribed to be used for some time after surgery, and further follow-up care appointments are made with your eye doctor. Glasses can only be adjusted several weeks after surgery.


© IQWiG (Institute for Quality and Efficiency in Health Care)
Bookshelf ID: NBK390312


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