Cataracts are a clouding of the lens of the eye. They are very common and usually develop as people age.

If you have a cataract things look blurry, as if you were looking through frosted glass. The only way to cure cataracts is by having an operation to remove them. After surgery, most people can see much better.

Key points

  1. Cataracts commonly develop with age. As you get older, you should get your eyes checked regularly.
  2. Diagnosis is made through an examination of the inside of the eye.
  3. Cataracts may be successfully removed through surgery.
  4. Cataract surgery is usually very safe and recovery is rapid.


For us to have perfect vision the lens inside our eye our must be clear. A cataract is when the lens becomes hazy or milky, making vision cloudy or blurry.

As you get older, your lens can change in two ways:

  • Your lens might get clumps in it. 
    Your lens is made up of mostly water and protein. Normally the protein is arranged in a precise way so that the lens is clear and light can easily pass through it. Cataracts occurs when the protein in your lens clump together. As the protein clumps grow larger they cloud more and more of the lens. This makes vision blurry.
  • Your lens might change colour.
    When you are younger, your lens is clear and colour-free. As you get older, it begins to turn yellow-brown. This can make it harder to see some colours, such as blues and purples. However, this change doesn't make your vision blurry.

Who gets cataracts?

Cataracts often develop as people age, with vision slowly getting worse. It is unusual to have a cataract before the age of 40. Other things that increase your risk of getting cataracts include:

  • severe eye injuries
  • diabetes and some medical conditions
  • smoking
  • exposure to sunlight and ultra violet light
  • photosensitising drugs (drugs that increase sensitivity to the sun).

Sometimes people are born with cataracts or a tendency to have cataracts earlier in life may run in a family.


Cataracts can begin as a mild haziness of the vision in direct or bright sunlight. As it worsens the vision can become very cloudy in all situations. Changing your glasses may help in the early stages but later on it can be very difficult to see, even with new glasses.

Common symptoms of cataract include:

  • cloudy or blurry vision
  • colours seem faded
  • glare – headlights, lamps, or sunlight may appear too bright. A halo may appear around lights
  • poor night vision
  • brownish tint to vision
  • double vision or multiple images in one eye – this symptom may stop as the cataract gets larger.

It is unusual to become totally blind from a cataract. As long as the rest of the eye works normally, a cataract operation can restore your vision at any stage.

How are cataracts diagnosed?

If you are concerned that you might have cataracts, it is important to see your local optometrist for an eye examination. Optometrists are able to detect eye diseases and help determine what is causing your vision to be blurry. You may find out you have cataracts when you go for a routine eye check-up.

You can also contact an eye surgeon (ophthalmologist) directly for this type of examination or to have your cataracts assessed and treated. Many eye care providers have lots of information available about cataracts and other eye diseases on their websites.

Your eye specialist can see if you have cataracts by doing a thorough eye examination. This may include:

An eye test

You will be asked to read letters from different rows of a chart. This measures how well you see at certain distances.

An examination of the inside of your eye

In this test, drops are put in your eye to make the hole in the centre of your eye (called your pupil) wider. This is called dilating your pupils. A special magnifying lens is used to look inside your eye to see if you have a cataract and how bad it is.  You can't see cataracts without looking into your eye, unless you have very bad ones. If you have a very bad cataract, the centre of your eye (your pupil) will be grey or white. By this stage your eyesight will be severely affected.

A tonometry test

In this test, an instrument is used to measure the pressure inside your eye. This test checks for other eye problems, such as glaucoma.


Cataracts can be treated at any stage. There is no need to wait for the cataract to ‘ripen’ before it can be treated, although this is a common misconception.

Normally cataract surgery is a short procedure, lasting about 15 minutes:

  • because the surgery does not last long most patients stay awake but have a light sedative to relax them during the treatment
  • often the eye can be numbed without the need for any needles by using anaesthetic jelly
  • you do not normally need to stay in a hospital overnight.

Treatment involves removing the cloudy natural lens inside your eye and replacing it with a new clear artificial lens that has been selected to give good vision. The new lens cannot be rejected by the body and cannot go cloudy like your natural lens can.

Surgery methods

There are now two ways of performing modern cataract surgery:

  • hand-held blade cataract surgery, and 
  • computer-controlled laser cataract surgery.

You can discuss different methods with your opthalmologist.

Once the hazy cataract has been removed, the new clear lens (an intra-ocular lens, or IOL) is rolled up and inserted through a small tube. It is then gently unfolded inside the eye and settled into place by the surgeon.

If both eyes require cataract surgery, they will be operated on at different times – giving the first eye a chance to recover before surgery on the second eye takes place.

Improving eye focus as well as removing cloudiness

Special types of lens implants (IOLs) have been developed to improve the focus of the eye as well as remove the cloudiness. Careful measurement of the eye before the surgery can help to design or choose an implant that minimises near-sightedness, far-sightedness and/or astigmatism.

Although the newly implanted lens is very clear and transparent it cannot change focus in exactly the same way as a young person’s natural lens does. This means reading glasses are frequently still needed afterwards. Many patients therefore choose to have their eyes corrected for a mixture of distance and near vision as a compromise, so they do not need to wear glasses full time.

Other kinds of implants called multi-focal IOLs can also be used to reduce the need for reading glasses after the surgery. If desired, patients can enjoy more freedom from glasses after cataract surgery, although glasses are still required for detailed tasks.

Risks and complications

Complications are extremely rare following cataract surgery. Cataract surgery is the most commonly performed operation in the Western world and is one of the safest prosthetic operations known to humankind.

What to expect after surgery

The following effects are temporary and disappear within a week or two:

  • the eye usually feels tender and light sensitive for a few days afterwards
  • everything may look brighter coloured
  • sometimes the eye may look bloodshot or have small red marks on the white of the eye
  • small floating spots or flickering effect in the vision.

Recovery period

It is very unlikely that you will need to stay overnight in hospital after cataract surgery. However, you should rest at home for several hours with the eye closed. Most patients can usually see better within two hours of cataract surgery and can often see well enough to drive within a day or two.

You should plan to take a few days off work and try not to strain your eyes during this time. Don't go swimming for one week and avoid contact sports for a few weeks after surgery.

Follow postoperative instructions

There are several things you can do to lessen your risks after surgery:

  • rest for several hours afterwards, as directed by your surgeon
  • take all the eye drops and medications exactly as prescribed
  • call your surgeon immediately if you develop any increasing pain or sensitivity to bright light
  • attend all your postoperative checks – it is typical for a patient to be seen the day after the operation and then again three to four weeks later.

Do not wait until the next check-up if you are concerned – it is always best to contact the surgeon immediately.

Self care

Regular eye checks are important

As you get older, you should get your eyes checked regularly. Also get your eyes checked straight away if you notice any changes or you think your vision is not as clear as it used to be.

Eye protection

Wear sunglasses to reduce glare and UV damage.

Learn more

Introduction to lens and cataracts  Optho Book by Dr Tim Root, Ophthalmologist.

Credits: Provided by ophthalmologist Dr Trevor Gray, Eye Institute, Auckland. Reviewed By: Health Navigator Editorial Team