This is what cataract can do to your eyes

  • Jan 13 , 2017

A cataract is a clouding of the lens in the eye that affects vision. Most cataracts are related to ageing. Cataracts are very common in older people. By the age of 80, more than half of the elder population either have a cataract or have had a cataract surgery.

A cataract can occur in either one or both eyes. It cannot spread from one eye to the other.

Types of cataracts include:

  • subcapsular cataract occurs at the back of the lens. People with diabetes or those taking high doses of steroid medications have a greater risk of developing a subcapsular cataract.
  • A nuclear cataract forms deep in the central zone (nucleus) of the lens. Nuclear cataracts usually are associated with ageing.
  • A cortical cataract is characterised by white, wedge-like opacities that start in the periphery of the lens and work their way to the center in a spoke-like fashion. This type of cataract occurs in the lens cortex, which is the part of the lens that surrounds the central nucleus.

Symptoms and signs:

  • A cataract starts out small and at first has little effect on your vision. You may notice that your vision is blurred a little, like looking through a cloudy piece of glass.
  • A cataract may make light from the sun or a lamp, seem too bright or glaring. Or you may notice when you drive at night that the oncoming headlights cause more glare than before.
  • Colours may not appear as bright as they once did. The type of cataract you have will affect exactly which symptoms you experience and how soon they will occur. When a nuclear cataract first develops, it can bring about a temporary improvement in your near vision, called ‘second sight.’
  • Unfortunately, the improved vision is short-lived and will disappear as the cataract worsens. On the other hand, a subcapsular cataract may not produce any symptoms until it's well-developed.

How cataract affects:

Clumps of protein reduce the sharpness of the image reaching the retina. The lens consists mostly of water and protein. When protein clumps up, it clouds the lens and reduces the light that reaches the retina. The clouding may become severe enough to cause blurred vision. Most age-related cataracts develop from protein clumps.

When a cataract is small, the cloudiness affects only a small part of the lens. You may not notice any changes in your vision. Cataracts tend to grow slowly, so vision gets worse gradually. Over time, the cloudy area in the lens may get larger, and the cataract may increase in size. Seeing may become more difficult. Your vision may get duller or blurrier. The clear lens slowly changes to a yellowish/brownish colour, adding a brownish tint to vision.

As the clear lens slowly colours with age, your vision gradually may acquire a brownish shade. At first, the amount of tinting may be small and may not cause a vision problem. Over time, increased tinting may make it more difficult to read and perform other routine activities. This gradual change in the amount of tinting does not affect the sharpness of the image transmitted to the retina.