Cataract is the clouding of the normally clear lens of the eyes. It is the most common cause of vision loss in people over 40 years and is also the leading cause of blindness in the world. In fact, it has been discovered that there are more cases of it compared to that of glaucoma, macular degeneration and diabetic retinopathy in the world. In the eyes there is an elastic transparent circular body known as the lens which bends (refract) light from objects to help us see. If this lens becomes cloudy or opaque, it prevents light from the object from being refracted by the lens hence, making it difficult to see clearly. It can affect one or both eyes. It occurs gradually until vision is finally lost.

Types of cataract

There are different types of cataract and they include;

  • Congenital cataracts: This type begins from childhood; some children are even born with cataract. It can be genetic or associated with intrauterine infections or trauma.
  • Nuclear cataracts: These are formed when the lens gradually begins to turn densely yellow and obstructs vision. It can progress to brown with time.
  • Cortical cataracts: This cataract begins as whitish, wedge-shaped opacities or streaks on the outer edge of the lens cortex. It grows slowly towards the centre until it covers the entire lens interfering with light passing through to the retina.
  • Posterior subscapular cataract: It starts as a small, opaque area that usually forms near the back of the lens, right in the path of light. It further interferes with your reading vision, reduces your vision in bright light, and causes glare or halos around lights at night.



  • Age; an increase in age leads to the increased chances of lens clouding (cataract)
  • Family history: If there is anyone in the family with cataract there is a chance of having it too.
  • Ultraviolet radiation
  • Previous eye injury
  • Past history of trauma to the eye
  • Certain diseases (e.g. obesity, hypertension, diabetes)
  • Personal behaviour (smoking, alcohol use)
  • Environment (air pollution, prolonged exposure to ultraviolet sunlight)


Signs and symptoms

  • Clouded or blurred vision
  • Increasing difficulty with vision at night
  • Sensitivity to light
  • Difficulty in reading and other activities
  • Frequent changes in eyeglass or contact lens prescription
  • Difficulty in recognising colours
  • Double vision in a single eye


Detection of cataract

Diagnosis of cataract can be done based on a good history and examination, however, some tests can be done in the confirmation of cataract. they include;

  • Visual acuity test:This measures how well you see at various distances.
  • Dilated eye exam:Drops are placed in your eyes to widen, or dilate, the pupils. Your eye care professional uses a special magnifying lens to examine your retina and optic nerve for signs of damage and other eye problems. After the exam, your close-up vision may remain blurred for several hours.
  • Tonometry:An instrument measures the pressure inside the eye. Numbing drops may be applied to your eye for this test to aid visibility.

Cataract Treatment

Cataract is a curable disease. Some of the steps needed in the treatment of cataract includes;

  • Use of visual aids, glasses for magnification
  • Cataract surgery: This is done by the ophthalmologist when cataracts have progressed enough to seriously impair your vision and affect your daily life. During surgery, the surgeon will remove the clouded lens and in most cases replace it with a clear plastic intraocular lens (IOL).
  • Wearing sunglasses and a hat with a brim to block ultraviolet sunlight may help to delay cataract.
  • Diet: fruits and vegetables, Vitamin A and E supplement helps make your vision clearer.
  • Avoid certain medications e.g. Corticosteroids, Miotics and Triparanol as this may increase the risk of cataract development.

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