Cataract is a cloudy or opaque area in the lens of the eye. Cataract is a clouding of the eye's natural lens, which lies behind the iris and the pupil. The lens works much like a camera lens, focusing light onto the retina at the back of the eye. The lens also adjusts the eye's focus, letting us see things clearly both up close and far away. Most cataracts are related to aging. Cataracts are very common in older people. Cataract can occur in either or both eyes. It cannot spread from one eye to the other. Cataracts may be present at or shortly after birth. These are called congenital cataracts. Cataracts are classified of three types permary is nuclear cataract is most commonly seen as it forms. This cataract forms in the nucleus, the center of the lens, and is due to natural aging changes. It cannot spread from one eye to the other.
Secondry is cortical cataract, which forms in the lens cortex, gradually extends its spokes from the outside of the lens to the center. Many diabetics develop cortical cataracts.Third is subcapsular cataract begins at the back of the lens. People with diabetes, high farsightedness, retinitis pigmentosa or those taking high doses of Steroids may develop a subcapsular cataract. Congenital cataracts can also be caused by infections affecting the mother during pregnancy, such as rubella. They are also associated with metabolic disorders such as galactosemia. Congenital cataracts risk factors include is inherited Metabolic diseases, a family history of cataracts, and maternal viral infection during pregnancy. Congenital cataracts may be inherited. The gene for such cataracts is dominant (autosomal dominant inheritance), which means that the defective gene will cause the condition even if only one parent passes it along.