A cataract is a clouding of the normally clear lens of your eye. For people who have cataracts, seeing through cloudy lenses is a bit like looking through a frosty or fogged-up window.

Clouded vision caused by cataracts can make it more difficult to read, drive a car (especially at night) or see the expression on a friend's face.

Most cataracts develop slowly and don't disturb your eyesight early on. But with time, cataracts will eventually interfere with your vision.

At first, stronger lighting and eyeglasses can help you deal with cataracts. But if impaired vision interferes with your usual activities, you might need cataract surgery. Fortunately, cataract surgery is generally a safe, effective procedure.

Signs & Symptoms of Cataracts include:

• Clouded, blurred or dim vision
• Increasing difficulty with vision at night
• Sensitivity to light and glare
• Seeing "halos" around lights
• Frequent changes in eyeglass or contact lens prescription
• Fading or yellowing of colors
• Double vision in a single eye

At first, the cloudiness in your vision caused by a cataract may affect only a small part of the eye's lens and you may be unaware of any vision loss. As the cataract grows larger, it clouds more of your lens and distorts the light passing through the lens. This may lead to signs and symptoms you're more likely to notice.

Types of cataracts

• Cataracts that affect the center of the lens (nuclear cataracts) 
  A nuclear cataract may at first cause you to become more nearsighted or even experience a temporary improvement in your reading vision. But with time, the lens gradually turns more densely yellow and further clouds your vision.
  
  As the cataract slowly progresses, the lens may even turn brown. Advanced yellowing or browning of the lens can lead to difficulty distinguishing between shades of color.
  
  
• Cataracts that affect the edges of the lens (cortical cataracts)
  A cortical cataract begins as whitish, wedge-shaped opacities or streaks on the outer edge of the lens cortex.
  
  As it slowly progresses, the streaks extend to the center and interfere with light passing through the center of the lens. People with cortical cataracts often experience problems with glare.
  
  
• Cataracts that affect the back of the lens (posterior subcapsular cataracts)
  A posterior subcapsular cataract starts as a small, opaque area that usually forms near the back of the lens, right in the path of light on its way to the retina.
  
  A posterior subcapsular cataract often interferes with your reading vision, reduces your vision in bright light, and causes glare or halos around lights at night.
  
  
• Cataracts you're born with (congenital cataracts)
  Some people are born with cataracts or develop them during childhood.. Congenital cataracts don't always affect vision, but if they do they're usually removed soon after detection.

Factors that increase your risk of cataracts include:

• Increasing age
• Diabetes
• Drinking excessive amounts of alcohol
• Excessive exposure to sunlight
• Exposure to ionizing radiation, such as that used in X-rays and cancer radiation therapy
• Family history of cataracts
• High blood pressure
• Obesity
• Previous eye injury or inflammation
• Previous eye surgery
• Prolonged use of corticosteroid medications
• Smoking

Treatment

The only effective treatment for cataracts is surgery.

When to consider cataract surgery

Talk with your eye doctor about whether surgery is right for you. Most eye doctors suggest considering cataract surgery when your cataracts begin to affect your quality of life or interfere with your ability to perform normal daily activities, such as reading or driving at night.

It's up to you and your doctor to decide when cataract surgery is right for you. For most people, there is no rush to remove cataracts because they usually don't harm the eye.

Delaying the procedure won't make it more likely that you won't recover your vision if you later decide to have cataract surgery. Take time to consider the benefits and risks of cataract surgery with your surgeon.

If you choose not to undergo cataract surgery now, your Doctor of optometry may recommend periodic follow-up exams to see if your cataracts are progressing. How often you'll see your optometrist depends on your situation.

Make an appointment for an eye exam if you notice any changes in your vision. If you develop sudden vision changes, such as double vision or blurriness, see your Doctor of optometry for proper diagnosis and treatment.