Cataract
What is a cataract?
A catarct is a clouding of the lens in the eye that affectss vision. Most cataracts are related to againg. Cataracts are very common in older people. By age 80, more than half of all Americans either have a cataract or have had cataract surgery. A cataract can occur in either or both eyes. It cannot spread from one eye to the other.
What is the lens?
The lens is a clear part of the eye that helps focus light, or an image, on the retina. The retina is the light sensitive tissue at the back of the eye. In a normal eye, light passes throuhg the transparent lens to the retina. Once it reaches the retina, light is changed into nerve signals that are sent the the brain. The lens must be clear for the retina to recieve a sharp image. If the lens is cloudy from a cataract, the image you see will be blurred.
Are there other types of cataracts?
Yes. Although most cataracts are related to againg, there are other types of cataracts.
Secondary Cataract: Cataracts can form after surgery for other eye problems, such as glaucoma. Cataracts alsp can develop in people who have other health issues, such as diabetes. Cataracts are sometimes linked to steroid use.
Traumstic Cataract: Cataracts can develop from an eye injury, sometimes years later.
Congenital Cataract: Some babies are born with cataracts or devolp them in childhood, often in both eyes. These cataracts may be so small they do not affect vision. If they do, the lenses may need to be removed.
Radiot Cataract: Cataracts can develop after exposure to some forms of radiation.
Causes and Risk Factors
What causes cataracts?
The lens lies behind the iris and the pupil. It works much like a camera lens. It focuses lights onto the retina at the back of the eye, where an image is recorded. The lens also adjusts the eye’s focus, letting us see things clearly both up close and far away. The lens is made mostly of water and protein. The protein is arranged in a precise way that keeps the lens clear and lets light pass through it. But as we age, some of the protein may clump together and start to cloud a small area of the lens. This is a cataract. Over time, the cataract may grow larger and cloud more of the lens, making it harder to see. REseacrhers suspect that there are everal causes of a cataract, suck as smoking and diabetes. Or, it may be that the protein in the lens just changes from the wear and tear it takes over the years.
How can cataracts affect my vision?
Age related cataracts can affect your vision in two ways:
Clumps of protein reduce the sharpness of the image reaching the retina. The lens consists mostly of water and protein. Then the protein clumps up, it clouds the lens and reduces the light that reaches the retina. The clouding may become severe enough to cause blurred vision. Most age related cataracts develop from prtein clumpings.