What Are Cataracts?

Medically Reviewed by Whitney Seltman, OD on February 13, 2024
10 min read

If you’re over 60 and your vision has gotten blurry or cloudy, you may have cataracts. It’s a common condition in older adults, and it can be treated by your eye doctor.

Cataracts usually form slowly. You may not know you have them until they start to block light. Then, you might notice:

  • Vision that’s cloudy, blurry, foggy, or filmy
  • Nearsightedness (in older people)
  • Changes in the way you see color
  • Problems driving at night (glare from oncoming headlights, for example)
  • Problems with glare during the day
  • Double vision in the affected eye
  • Trouble with eyeglasses or contact lenses not working well

Cataracts form when protein builds up in the lens of your eye and makes it cloudy. This keeps light from passing through clearly. It can cause you to lose some of your eyesight. There are many types of cataracts.

Nuclear cataracts

Also called a nuclear sclerotic cataract, this is the kind doctors see most. Anyone who lives long enough usually ends up with one.

They form in the center of the lens, known as the nucleus. As they get worse, your reading vision may actually get better. It's called second sight, but it doesn't last long.

Over time, the lens hardens and turns yellow or even brown. You have a hard time seeing small details, colors get less rich, and you see halos around bright objects at night.

Cortical cataracts

These take shape on the outside edge of your lens, called the cortex. They start as white wedges, like triangles that point toward the center of your eye. As they grow, they scatter light.

The main symptom is glare. You may find it hard to drive at night. They can also make your vision hazy, like you're looking through a fog. It may be hard to tell similar colors apart or to judge how far away an object is.

Since they can spell trouble for both near and distance vision, you typically get them removed early on.

Posterior subcapsular cataracts

These form just inside the back of your lens capsule, the part of your eye that surrounds the lens and holds it in place. They're directly in the path of light as it passes through the lens.

They're quicker to progress than other cataracts, and you may get symptoms within months. They affect your close-up vision and make it harder to see in bright light.

Anterior subcapsular cataracts

This type forms just inside the front of your lens capsule. An injury or swelling in your eye can lead to one. So can a type of eczema called atopic dermatitis.

Congenital cataracts

These are cataracts that you're born with or that form when you're a child. Some are linked to your genes, and others are due to an illness, like rubella, that your mother had during pregnancy.

When they're small or outside the center of the lens, they may not need treatment. But when a baby's born with one that blocks vision, a doctor needs to remove it because it can stop the eye from learning to see.

Traumatic cataracts

Many kinds of injuries can lead to a cataract. You can get one if you're hit in the eye by a ball or get hurt from a burn, chemical, or splinter. The cataract could come on soon after the injury or not show up until years later.

Secondary cataracts

When another condition or a medical treatment leads to a cataract, doctors call it secondary. Diabetes, taking steroids like prednisone, and even cataract surgery are possible causes.

Radiation cataracts

You may know that it's important to protect your skin from the sun's ultraviolet (UV) radiation, but it can take a toll on your eyes, too. You can sometimes get cataracts if you spend too much time in the sun without eye protection.

People who work outdoors, like fishers and farmers, are more likely to get this kind of cataract. To prevent it, wear sunglasses with 100% UVA and UVB protection.

Cataracts are also a possible side effect from radiation therapy for cancer.

Lamellar or zonular cataracts

This type typically shows up in younger children and in both eyes. The genes that cause them are passed from parent to child.

These cataracts form fine white dots in the middle of the lens and may take on a Y shape. Over time, the whole center of the lens may turn white.

Posterior polar cataracts

You get these on the back center of your lens, and they're often due to genes that are passed down through your family.

Posterior polar cataracts often don't cause symptoms, which is good because they're hard to remove.

Anterior polar cataracts

They form on the front and center of your lens and look like small white dots. These cataracts typically don't bother your vision.

Post-vitrectomy cataracts

Vitrectomy is surgery to remove your vitreous, the clear gel at the center of your eye. The operation can help with certain eye problems but may lead to a cataract.

Christmas tree cataracts

Also called polychromatic cataracts, they form shiny, colored crystals in your lens. They're most common in people who have a condition called myotonic dystrophy.

Brunescent cataracts

If you don't treat a nuclear cataract, it turns very hard and brown. This is called brunescent.

It makes it hard for you to tell colors apart, especially blues and purples. Surgery to remove it is harder, longer, and riskier than when you get treatment earlier on.

Diabetic snowflake cataracts

This is a rare type of cataract that can happen if you have diabetes. It gets worse quickly and forms a gray-white pattern that looks like a snowflake.

To find out if you have cataracts, your doctor will want to know all about your symptoms. They’ll look closely at your eyes and may do some tests including:

  • Visual acuity test. This is a fancy way of saying "eye chart exam." Your doctor will ask you to read letters from a distance to find out how sharp your vision is. First, you'll try it with one eye and then the other. They may also then do a glare test, where they shine a bright light in your eye and then ask you to read the letters.
  • Slit-lamp exam. This uses a special microscope with a bright light that lets your doctor check different parts of your eye. They'll look at your cornea, the clear outer layer. They'll also examine the iris -- the colored part of your eye -- and the lens that sits behind it. The lens bends light as it enters your eye so you can see things clearly.
  • Retinal exam. Your doctor puts drops in your eyes to widen your pupils, the dark spots in the middle that control how much light gets in. This lets them get a good look at the retina -- the tissue around the back of your eyes -- and a better view of the cataract.

Surgery is the only way to treat cataracts, but you may not need it right away. If you catch the problem at an early stage, you might be able to get by with a new prescription for your glasses. A stronger lens can make your vision better for a while.

If you have trouble reading, try a brighter lamp or a magnifying glass. If glare is a problem for you, check out special glasses that have an anti-glare coating. They can help when you drive at night.

Keep close tabs on how your cataracts affect the way you see. When your vision troubles start to get in the way of your daily routine -- especially if they make driving dangerous -- it's time to talk to your doctor about surgery.

Cataract surgery

There are several kinds of operations for cataracts, but they all have one thing in common: Your surgeon takes out the cloudy lens and replaces it with an artificial one.

You might feel a little uncomfortable with the idea of an operation on a sensitive spot like your eye. But it's a very common procedure. You'll get medicine called local anesthesia to numb your eye. You’ll be awake but sedated, and you won't feel anything.

It usually takes about 15 to 20 minutes, and you don't need to stay overnight in a hospital. If you have cataracts in both eyes, your doctor will wait until your first eye heals before they perform surgery on the second. More than 95% of people who have this done say they can see better afterward.

  • Small-incision surgery. You may also hear your doctor call this phacoemulsification. Your surgeon makes a tiny cut on your cornea. They put a small device in your eye that gives off ultrasound waves that break up your cloudy lens. Then, they take out the pieces and put in the artificial lens.
  • Large-incision surgery. This isn’t done as often, but doctors sometimes suggest it for larger cataracts that cause more vision trouble than usual. It's sometimes called extracapsular cataract extraction. Your surgeon takes out your clouded lens in one piece and swaps it out for an artificial one. You'll probably need a little more time to heal from this surgery than from the small-incision type.
  • Femtosecond laser surgery. In this operation, your surgeon uses a laser to break up the lens. As with the other types, they'll then put in the new lens. Your doctor may suggest this if you also have an astigmatism, a curve of your cornea that makes your vision blurry. Your surgeon can treat that problem during the cataract surgery by using the laser to reshape your cornea.

After cataract surgery

For most people, recovery goes smoothly. How long it takes depends on which type of surgery you get. But in general, you'll notice that your vision gets much better a few days afterward. After about a week or two, you can go back to doing all the things you enjoy.

As with any surgery, there are risks. It's rare, but you could have an infection or bleeding. There's also a chance your retina could pull away from the tissues at the back of your eye. This is called a detached retina.

Some people have an issue after cataract surgery called posterior capsule opacification (PCO). Your vision may get cloudy again because the capsule in your eye that holds the artificial lens in place gets thicker. Laser surgery called YAG can fix the problem. Sometimes, this happens 1 year after cataract surgery, but other times, it doesn’t happen until 10 years later.

Some children are born with cataracts if the lens did not form the way it should during the pregnancy.

These congenital cataracts can be caused by a chromosomal problem like Down syndrome. They might also be hereditary, meaning a baby’s parent may have them.

Cataracts that form after birth are called acquired. Causes include:

  • Eye injury
  • Diabetes
  • Complications from eye problems
  • Radiation treatment
  • Steroids

Sometimes, doctors don’t know for sure why a child gets a cataract.

How can I find out if my child has cataracts?

You can’t always see cataracts. But when you can, they usually look like a white or gray spot or reflection inside the pupil.

It’s important to get your child’s vision checked regularly. The earlier you find cataracts, the better their eyesight will be in the long term. The first vision screening takes place when your child is a newborn. The doctor will check their eyes for cataracts and other problems. They’ll continue to have vision tests throughout infancy and childhood when they get regular checkups.

It can be hard for children to explain vision problems to their parents. They might not even know that something’s wrong with the way they see. But when they do, they may say they can’t see as well as they used to. They might also say that they see two of everything (“double vision”) or that the lights are too bright. Maybe they see a glare or halo, or colors just don’t look as bright as they should.

By the time your baby is about 4 months old, they should be able to look around a room and track things with their eyes. If they can’t, ask your doctor to check their eyes.

Another way you can tell your child might have cataracts: their eyes are misaligned, meaning they don’t look in the same direction.

What’s the treatment?

If your child’s cataract is small and doesn’t affect their vision, it may not need to be removed. But if it does affect their eyesight, it should be treated as soon as possible. Otherwise, their vision can be affected in the long term.

Your doctor will give your child general anesthesia, so they won’t be awake or feel anything during the operation. They’ll use special tools to break up the lens and remove it through a very small cut.

From here, your doctor has some options:

  • Artificial lens (still being investigated for use in very young children)
  • Contact lenses
  • Eyeglasses (most children need them even after successful surgery)

Sometimes, if your child has cataracts in both eyes -- or one was worse than the other -- they may develop a condition called amblyopia. It happens when one eye is stronger than the other. The doctor can treat it.

What happens after surgery?

Most likely, you and your child can go home the same day.

Very young children get over this surgery quickly and usually are back to normal in about a day. Older kids might be a little uncomfortable for a few days, mostly because their eyes may be itchy or scratchy.

Your doctor will give you prescription eye drops and directions on how to give them to your child.

If they had a cataract removed from just one eye, they may have to wear a patch on the other for a time. That will help strengthen the eye that was operated on.

Keep all follow-up appointments after the surgery. That way, your doctor can make sure your child is healing and can see the world clearly -- now and well into adulthood.

Doctors don’t know exactly what causes cataracts, so there’s no proven way to prevent them. But because cataracts and other conditions like glaucoma are common in older adults, it’s important to get your eyes checked regularly. This is really important if you have a family history of eye problems or have been exposed to things that could cause trouble with your eyes.

Adults should see an eye doctor at least every 2 years until age 50 and every year after that.

If you have a history of eye problems or other conditions, such as diabetes, that raise your odds for eye disease, you may need eye exams more often.