A cataract is the clouding of the lens which is the part of the eyes responsible for focusing light and producing clear, sharp images. A cataract occurs when the crystalline lens of the eyes become cloudy or opaque as a result of age, illness, or trauma. This cloudiness can interfere with the eye’s natural ability to direct light and focus an image on the retina. As a result, individuals with cataracts frequently experience a loss of vision.
The most common cause of the cataract is the deterioration of the natural structure within the lens of the eye with age. There may be other causes like diabetes, kidney disease, glaucoma, smoking, eye injury, infection, and inflammation inside the eyes. Prolonged use of certain medications can also lead to cataract formation. Common symptoms are blurry vision, the color that seems faded, glare, not being able to see at night, double vision, frequent prescription changes in your eyewear.
Adults over the age of 40 should regularly schedule eye examinations on an annual basis to determine whether cataracts or other eye disorders are present.
A thorough examination by an eye specialist usually will include:
- A visual acuity test to measure the clarity of various distances
- Pupil dilation to examine the lens and retina for other eye problems.
- Tonometry a standard procedure to measure fluid pressure inside the eyes.
Patients with cataract often experience the following symptoms:
- Blurring vision
- Glare or sensitivity to light especially during night hours
- Double vision
- Frequent changes in eyeglass prescription
- Difficulty in reading in low light
- Declining night vision
- Fading or yellowing of colors
Types of cataract
- Secondary cataract
Cataracts can form after the surgery for other eye problems, such as glaucoma. Cataracts also can develop in a person who has other health problems, such as diabetes. Cataracts are sometimes linked to steroid use also.
- Traumatic cataract
Cataracts can develop after an eye injury, sometimes years later.
- Congenital cataract
Some newborn babies are born with cataracts or develop them in childhood, often in both eyes. This cataract may be so small that it does not affect the vision. If they do, the lenses may need to be removed.
- Radiation cataract
Cataracts can develop after exposure to some types of radiation.
Causes and risk factor
The lens lies behind the iris and the pupil. It works much like a camera lens. It focuses light 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 of mostly water and protein. The proteins are arranged in a precise way that keeps the lens clear and lets light pass through it.
But as we age some 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. Researchers suspect that there are several causes of cataracts, such 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.