A cataract is a clouding of the eye’s natural lens, which lies behind the iris and the pupil. A cataract usually begins when proteins in the eye form clumps that prevent the lens from sending clear images to the retina. The retina works by converting the light that comes through the lens into signals. It sends the signals to the optic nerve, which carries them to the brain. Cataracts usually develop slowly and eventually interfere with your vision. You may develop cataracts in both eyes, either concurrently or sequentially. Cataracts are common in people over 40 years old.
Types of cataracts include:
- A 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 centre 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.
Cataracts usually start small and don’t affect your vision too much initially. You may begin noticing blurriness in your sight, which may get worse over time. You also notice a sensitivity to light, or colours seeming duller than usual.
The type of cataract you have will affect which symptoms you experience and how soon they 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. If you think you have a cataract, make an appointment with Dr Khantsi offices in Midrand Johannesburg or Pretoria Eye Institute in Arcadia Pretoria.