A cataract is a clouding of the transparent dome-shaped surface of the eye that prevents light from reaching the retina. It results in blurred vision, glare and halos around objects.
There are three types of cataracts:
- Nuclear cataracts, which form in the nucleus or center of the lens. These are usually related to age.
- Cortical cataracts, which form in the cortex, outside of the eye lens. Over time, this cataract extends from the outside to the inside of the lens. They are common in diabetic patients.
- Subcapsular cataracts, which form at the back of the lens. This type of cataract is common in diabetics, people taking steroid medication and those who are farsighted or have retinitis pigmentosa.
When a patient has small or slowly developing cataracts, they can compensate temporarily with prescription glasses or bifocals or avoiding activity such as driving at night.
Eventually, surgery to replace the clouded lens may be needed.