A cataract is a clouding of the lens of the eye. Cataracts primarily develop in the elderly and are the most common cause of visual impairment in the world.

The effect of a cataract on vision

A cataract usually develops in both eyes at the same time, but can also affect only one eye. Cataracts can progress at different rates, causing vision problems in only one eye.

A cataract may not affect vision in its early stages and disturbing vision changes might occur only after several months or years.

The main symptoms of a cataract are blurred vision, decreased visual acuity and fading of colour vision.

Other symptoms of a cataract may include:

  • sensitivity to light;
  • impaired night vision;
  • double vision or diplopia;
  • halos or circles of light around bright light sources.

Risk factors

Some factors increase your risk and speed the progression of cataracts. The most common are:

  • UV radiation;
  • diabetes;
  • high blood pressure or hypertension;
  • smoking;
  • obesity;
  • excessive alcohol consumption;
  • eye injuries.

Diagnosis and treatment

Various methods are used to diagnose cataracts, including the following.

Slit-lamp examination

A slit-lamp is a device with a microscope that allows very precise examination of the eye and detection of a potential cataract. If necessary, eye dilating drops are used.

Eye examination

During an eye examination, the refractive error of your eye and the corrective power that gives you the best possible visual acuity are determined. If your eyeglass prescription has changed and your vision can no longer be fully corrected with eyeglass lenses, it might indicate a cataract in its early stages.

A cataract does not always require immediate treatment, especially if it does not disrupt your vision. In the case of an early cataract, renewing your eyeglass prescription may be sufficient to achieve satisfactory visual acuity.

However, if a cataract starts to affect your quality of life, you may be recommended to undergo cataract surgery. During the surgery, the opaque lens is removed and replaced with an artificial lens.