What Is Cataract
The images we see are made up of light reflected from the objects we look at. This light enters through two surfaces that focus an image: the cornea and the natural lens of the eye. The cornea is the clear dome-like structure at the front of the eye that focuses light as it enters the eye. The lens fine-tunes the light before passing it onto the retina, located at the back of the eye. The retina records the light and then converts it into an electrical signal. From here, the signal is transmitted to your brain through the optic nerve, which is similar to the cable that connects a video camera to a TV. The brain then processes the signal to let you see the image.
A cataract is a clouding of the lens in the eye that impedes the passage of light and affects vision.
For most of our lives, the natural lens is flexible and clear — allowing us to focus on objects both far and near. At around age 45 the lens becomes less flexible and loses its ability to change focus. It becomes difficult to see objects up close. Eventually it hardens and becomes cloudy and discolored. A cloudy, discolored lens interferes with light passing through it, causing blurry vision. When the clouding blocks enough light and impairs vision to the point where glasses won’t even help, the lens is generally considered to have become a cataract.
Prevalence of Cataract Disease
- In the United States, 24,409,978 million people age 40 and older have cataracts, a 19 percent increase from year 2000 to year 2012!
- Cataract is responsible for 51% of world blindness, which represents about 20 million people (2010). Cataract remains the leading cause of blindness.
Often cataracts develop slowly. People typically don’t realize their vision has deteriorated until the cataracts interfere with something they need or like to do. Some people start to have trouble reading, watching TV or driving at night.
Typical cataract symptoms include:
- Blurry vision
- Cloudy or dim vision
- Change in vibrancy of colors or yellowing of colors
- Glare or halos around lights
- Sensitivity to light and glare
Types of Cataracts
Most cataracts are age-related. There are, however, other types:
- Congenital cataract. Some babies are born with cataracts or develop them in childhood, often in both eyes.
- Secondary cataract forms after surgery for other eye problems, such as glaucoma. Cataracts may also develop in people who have diabetes and those using steroids.
- Traumatic cataract develops after an eye injury. This can happen several years after the injury
- Radiation cataract may also develop to patients who underwent radiation treatment of therapy.