Cataract

A cataract is a clouding of the clear lens inside the eye. The cloudiness keeps light from reaching the back of the eye, so it becomes harder to see clearly. A cataract can form in one eye or both, but it does not spread from one eye to the other.

Cataracts usually develop slowly, and as they worsen, vision becomes blurry or dim. Brighter lighting or new glasses may help at first. If a cataract starts to get in the way of daily life, surgery may be needed. Left untreated, cataracts can cause severe or even permanent loss of vision.

Causes

Most cataracts are part of normal aging. Protein in the lens clumps together, and over time the clumps grow larger and thicker, making it harder to see. The lens may also turn yellow or brown, which changes how colors look. Cataracts can also follow an eye injury or surgery for another eye condition, such as glaucoma.

Who gets them

Cataracts are very common in older adults. By age 80, more than half of all Americans either have a cataract or have had cataract surgery. Risk rises with age, and it may also be higher for people who:

• have certain health problems, such as diabetes;
• have a family history of cataracts;
• have had an eye injury or eye surgery;
• take steroid medicines, used for conditions such as arthritis or allergies;
• smoke;
• drink excessive amounts of alcohol;
• have spent a lot of time in the sun.

Symptoms

Because cataracts develop slowly, they may go unnoticed at first, which is why regular eye exams matter. Common symptoms include:

• blurry or cloudy vision;
• colors that look faded;
• glare from headlights, lamps or sunlight that seems too bright;
• halos around lights;
• poor vision at night;
• double vision, which may go away as the cataract grows;
• frequent changes in a glasses or contact lens prescription;
• trouble reading or doing other everyday tasks.

These can also be signs of other eye problems, so it is worth raising them with a provider.

Diagnosis

A comprehensive eye exam is the best way to check for cataracts. It includes several tests of vision and eye health, among them a dilated eye exam: drops widen the pupils so more light enters the eye and the provider can clearly see the tissues at the back.

Treatment

Surgery is the only way to remove a cataract. At first, new glasses and brighter lighting may be enough. When a cataract gets in the way of everyday activities like reading, driving or watching TV, surgery is an option. The surgeon removes the cloudy lens and replaces it with an artificial lens, called an intraocular lens (IOL).

Protecting your eyes

Anyone worried about cataract risk can ask a provider whether there is anything to lower it. Some ways to protect the eyes:

• Wear sunglasses and a wide-brimmed hat to block ultraviolet (UV) sunlight, which can help delay cataracts.
• Protect your eyes from injury when using power tools or playing certain sports.
• Eat a healthy diet with plenty of fruits, vegetables, leafy greens, nuts and whole grains.

Sources

• MedlinePlus, U.S. National Library of Medicine, "Cataract." https://medlineplus.gov/cataract.html
• MedlinePlus credits the information to the National Eye Institute, NIH.