What is a cataract?

A cataract is a clouding of the lens in the eye that affects vision. Most cataracts occur with age, infact by age 80, more than half of all Americans either have a cataract or have had cataract surgery.

Image of the eye

What is the lens?

The lens is a clear part of the eye that helps to 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 through the transparent lens to the retina. Once it reaches the retina, light is changed into nerve signals that are sent to the brain.

The lens must be clear for the retina to receive a sharp image. If the lens is cloudy from a cataract, the image you see will be blurred.

Are there other types of cataract?

Yes. Although most cataracts are related to aging, there are other types of cataract:

  1. Secondary cataract. Cataracts also can develop in people who have other health problems, such as diabetes. Cataracts are sometimes linked to steroid use.
  2. Traumatic cataract. Cataracts can develop after an eye injury, sometimes years later.
  3. Congenital cataract. Some babies are born with cataracts or develop them in childhood, often in both eyes. These cataracts may be so small that they do not affect vision. If they do, the lenses may need to be removed.
  4. Radiation cataract. Cataracts can develop after exposure to some types of radiation.

Normal vision
Normal vision

As viewed by a cataract person
The same scene as viewed by a person with cataract

What are the symptoms of a cataract?

The most common symptoms of a cataract are:

  • Cloudy or blurry vision.
  • Colors seem faded.
  • Glare, especially at night with car headlights.
  • Poor night vision.
  • Double vision.
  • Large and frequent prescription changes.
  • These symptoms also can be a sign of other eye problems. If you have any of these symptoms, check with your eye care professional.


How is a cataract treated?

Cataract surgery is a very common procedure. In fact, over 3 million people undergo the surgery every year, making it the most common surgery performed in the United States. When glasses can no longer improve eyesight sufficiently, cataract surgery should be considered. It is a relatively painless procedure and, has been very successful in restoring vision over the past thirty years.  Traditional cataract surgery involves a process called phacoemulsification.  A tiny incision is manually created in the cornea, a thin ultrasound probe is inserted, and ultrasonic vibration is used to dissolve the clouded lens.  The clouded lens is replaced with an intraocular lens (IOL).  The IOL will remain permanently inside the eye in this location, acting similar to an intraocular contact lens.  IOLs cannot be felt or sensed in any way by the patient. The patient is then managed by their eye physician for 3 to 4 weeks while also taking prescription eye drops throughout this time. 

A dramatic improvement in vision is usually noticed after surgery given there are no other reasons for decreased vision.  Many people are surprised by the sudden improvement, and wonder why they didn’t do the surgery sooner!


Information provided by NEI and FeinerMan Vision Center