A cataract is a clouding of the eye’s natural lens, which can make it harder for you to see. Cataracts are the most common cause of vision loss in people over age 40 and is the principal cause of blindness in the world. Cataracts develop when protein builds up in the lens of your eye, making it cloudy. This prevents light from passing clearly through the lens, causing some loss of vision. New lens cells form on the outside of the lens and the older cells are compacted into the center of the lens, forming the cataract.
Types of cataracts include:
- Nuclear: A nuclear cataract forms deep in the central zone (nucleus) of the lens and is the most common type of cataract. Because opacity develops in the center of the lens, known as the central nucleus, nuclear cataracts interfere with a person’s ability to see objects in the distance. Usually the result of advancing age, nuclear cataracts can take years to develop and often give the nucleus a yellow tint.
- Subcapsular: 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. These cataracts progress the most rapidly. While nuclear cataracts take years to develop, subcapsular cataracts reach an advanced stage within a matter of months.
- Cortical: A cortical cataract begins at the outer rim of the lens and gradually works toward the central core. This type of cataract resembles spokes on a wheel. This type of cataract occurs in the lens cortex, which is the part of the lens that surrounds the central nucleus. Patients with cortical cataracts often notice problems with glare or a “halo” effect around lights. They may also experience a disruption of both near and distance vision.