Cataracts are caused by chemical changes that occur within the lens of the eye. Our eyes’ lenses are made up of water and proteins that are arranged in a way that keeps the lens clear and allows light to pass through. However, the proteins can begin to clump together causing the lens to become cloudy, impeding the passage of light. Since the lens helps to focus light on the retina to form images, this cloudiness affects vision.

At first the clouding may have little effect on your vision depending on its location on the lens. Over time the cataract may grow larger, clouding more of the lens and making it harder to see. Cataracts develop gradually and painlessly.​ 

cataract eye

Causes of Cataracts

Developing cataracts is a normal part of growing older. Most people start to develop cataracts after the age of 65, but some people in their forties and fifties can also develop cataracts. Occasionally children can be born with the condition, or a cataract may develop after eye injuries, inflammation, and some other eye diseases.

Certain things make you more susceptible to developing cataracts:

  • Trauma – having an eye injury can cause the injured eye to develop a cataract.
  • Medications – some prescription drugs can cause cataracts, for example steroids.
  • Eye surgery – surgery for a retinal problem will likely lead to cataracts in the affected eye at some point in the future.
  • Eye conditions – other eye conditions, such as retinitis pigmentosa, glaucoma or uveitis, may also cause cataracts.
  • Having high myopia (being very short sighted) may cause cataracts.

Symptoms of Cataract

Cataracts normally develop very slowly. At first, the changes to your sight may be slight, but as your cataracts get worse you’ll start to notice symptoms such as:

  • You feel like your glasses are dirty and need cleaning, even when they don’t.
  • Your sight is misty and cloudy.
  • You’re more sensitive to light – bright sunlight or car headlamps may glare more.
  • You have difficulty seeing at night.
  • Everything looks a little more washed out than it should be.

Eventually, almost all people with cataracts will find that their sight has turned misty or cloudy, and more things have become difficult to see.

As a cataract develops, you may become sensitive to bright lights or experience glares and halos around lights. These symptoms may interfere with everyday activities such as driving, reading or watching TV. When such symptoms occur, we recommend visiting eye health specialist without delay.


Cataracts are treated by surgery, during which the cloudy lens is removed and replaced by an artificial lens. Cataract surgery is one of the most successful procedures in existence. There isn’t any medicine or drops that can remove cataracts – surgery is the only way to treat them.


Canadian National Institute for TheBlind (CNIB)​

The International Agency for thePrevention of Blindness (IAPB)

Royal National Institute of BlindPeople (RNIB)​