A cataract is the clouding of the normally clear lens of the eye.


A cataract is the clouding of the normally clear lens of the eye. Cataracts are common among older people and are usually a “normal” part of the ageing process. Vision deteriorates and colours fade progressively. Cataracts can only be removed by surgery.


Main symptoms

  • Vision deteriorates slowly and the patient becomes increasingly short-sighted
  • Seeing through cloudy lenses is like looking through a foggy window, and colours look matte (shades of grey)
  • Light from the sun or a lamp seems too bright or glaring (car headlights)

Other symptoms

  • The clouding of the lens slowly becomes visible from the outside as a silvery, whitish to brownish blemish behind the pupil

Causes and treatment


  • Age-related cataracts (most common)
  • Diabetes mellitus
  • Underactive thyroid (hypothyroidism)
  • Traumatic injury to the lens
  • Congenital cataracts
  • Medication (in particular long-term use of cortisone)

Further treatment by your doctor / in hospital

Possible tests
  • Examination of the eye with an ophthalmoscope (by an eye doctor)
Possible therapies
  • Operation to remove the cloudy lens and replace it with an artificial lens

Not every developing cataract has to be operated on immediately, and the best time for surgery should be discussed with the eye doctor.

What can I do myself?

  • Tinted glasses protect against the glare
  • Wear protective glasses, if necessary
  • Effective glycaemic control helps diabetes patients to avoid cataracts

Get a personal Preventive Care Recommendation now.

When to see a doctor?

  • When vision impairment occurs or continues to worsen



Exclusion of liability

CSS offers no guarantee for the accuracy and completeness of the information. The information published is no substitute for professional advice from a doctor or pharmacist.