Cataracts are cloudy areas that form on your eye’s lens. Age-related cataracts are the most common type. Symptoms include blurry vision and glare around lights. Cataract surgery removes your clouded lens and replaces it with a clear artificial lens called an IOL. Providers recommend surgery when cataract symptoms interfere with your daily life.

Symptoms of cataracts include:

• Clouded, blurred or dim vision.
• Trouble seeing at night.
• Sensitivity to light and glare.
• Need for brighter light for reading and other activities.
• Seeing “halos” around lights.
• Frequent changes in eyeglass or contact lens prescription.
• Fading or yellowing of colors.
• Double vision in one eye.

At first, the cloudiness in your vision caused by a cataract may affect only a small part of the eye’s lens. You may not notice any vision loss. As the cataract grows larger, it clouds more of your lens. More clouding changes the light passing through the lens. This may lead to symptoms you notice more.

What causes cataracts?

Cataracts are caused by changes to the lens of your eye, mostly associated with ageing and exposure to ultraviolet light. Cataracts develop when proteins in the lens are damaged and clump together. This reduces the amount of light that can pass through the lens to the retina, which leads to a loss of vision. As you get older it’s normal that these proteins in the lens of the eye start to break down and clump together. This causes the characteristic cloudiness in the lens that is a cataract. Exposure to ultraviolet light also increases the risk of cataracts — experts think this happens through oxidative stress — the same process that causes skin damage from the sun.

Types of cataracts

• Cataracts affecting the center of the lens, called nuclear cataracts. A nuclear cataract may at first cause objects far away to be blurry but objects up close to look clear. A nuclear cataract may even improve your reading vision for a short time. But with time, the lens slowly turns more yellow or brown and makes your vision worse. It may become difficult to tell colors apart.
• Cataracts that affect the edges of the lens, called cortical cataracts. A cortical cataract begins as white, wedge-shaped spots or streaks on the outer edge of the lens cortex. As the cataract slowly grows, the streaks spread to the center and affect light passing through the lens.
• Cataracts that affect the back of the lens, called posterior subcapsular cataracts. A posterior subcapsular cataract starts as a small spot that usually forms near the back of the lens, right in the path of light. A posterior subcapsular cataract often affects your reading vision. It also may reduce your vision in bright light and cause glare or halos around lights at night. These types of cataracts tend to grow faster than others.
• Cataracts you’re born with, called congenital cataracts. Some people are born with cataracts or develop them during childhood. These cataracts may be passed down from parents. They also may be associated with an infection or trauma while in the womb.

  These cataracts also may be due to certain conditions. These may include myotonic dystrophy, galactosemia, neurofibromatosis type 2 or rubella. Congenital cataracts don’t always affect vision. If they do, they’re usually removed soon after they’re found.

Risk factors.

Factors that increase your risk of cataracts include:

• Increasing age.
• Diabetes.
• Getting too much sunlight.
• Smoking.
• Obesity.
• Family history of cataracts.
• Previous eye injury or inflammation.
• Previous eye surgery.
• Prolonged use of corticosteroid medicines.
• Drinking excessive amounts of alcohol.

Prevention