Updated on 

May 24, 2022

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Cataracts - Symptoms, Causes, Diagnosis & Treatment

What are Cataracts?

A cataract is a common age-related eye disorder that develops when an area of the eye's lens (clear inner part of the eye) becomes foggy or cloudy. As you age, this breakdown and clumping of proteins can cause cataracts. 

The eye lens is naturally clear and responsible for focusing light on the retina. This is the layer at the back of the eye that turns light into electrical signals for the brain to process. When the lens becomes foggy, it causes dull and blurry vision.

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Cataracts typically develop slowly over time and are painless. You may not notice a change in vision until the cataract progresses and covers more of the lens.

If left untreated, cataracts can eventually lead to blindness. It’s the number one cause of preventable blindness worldwide and the leading cause of vision loss in the United States.4

Types of Cataracts 

Cataracts are a common part of aging, with 17.5% of Americans over 40 developing cataracts in one or both eyes.4 

While age-related cataracts are the most common, there are other types of cataracts, including:

  • Congenital cataracts. Infants can develop cataracts before birth. Common causes of congenital cataracts include a mother having an infection during pregnancy, Down syndrome, and diabetes.
  • Traumatic cataracts. Blunt force trauma and eye injury can cause cataracts to develop immediately or years later. 
  • Secondary cataracts. Underlying medical conditions (diabetes), medications (steroids), and complications from certain eye surgeries (glaucoma) can also result in cataracts.

Symptoms of Cataracts 

Because cataracts progress over time, vision loss may take years to develop. 

Common cataract symptoms include:

What Causes Cataracts? 

Age is the most significant factor for developing cataracts, typically starting between 40 and 50. Over half of Americans over the age of 80 have developed cataracts.1 

three main layers of the eye

While the exact cause of cataracts is unknown, other than age, the greatest cataract risk factors include:

  • Smoking
  • Excessive alcohol use
  • Family history of cataracts
  • Diabetes or high blood sugar
  • Steroids 
  • Diuretic medications
  • Unprotected exposure to the sun (not wearing sunglasses or hats)
  • Eye surgery or eye injury
  • Radiation and chemotherapy treatment

When to See a Doctor for Cataracts

Cataracts develop slowly. You may not notice changes in vision until cloudiness spreads over the lens, blocking light from reaching the retina. This can take several years. 

Experts recommend seeing an eye doctor when you start to experience vision changes, including:

  • Blurry vision that interferes with daily activities and hobbies
  • Struggling with up-close tasks such as reading, sewing, and using a phone
  • Difficulty driving at night
  • Images develop a brown or yellow tint
  • Double vision 
  • Eye prescription keeps changing
  • Eye sensitivity to light
  • Second sight (when vision gets better for a while but then worsens)

When cataract symptoms interfere with everyday life, it might be time to consider cataract surgery. Talk to your eye doctor about treatment options. 

Diagnosing Cataracts

A cataract diagnosis occurs during a comprehensive eye exam with a licensed ophthalmologist. The eye doctor will dilate your eyes to examine their health with a slit lamp (microscope) and look for signs of cataracts.

During the eye exam, the ophthalmologist will also:

  • Ask about family and medical history
  • Conduct a visual acuity test (clarity and distance vision)
  • Look for lens opacity and cloudiness 
  • Perform a retinal exam to look at the retina and optic nerve (communication pathway between the eyes and brain)
  • Check for glaucoma (increased intraocular pressure)

People over the age of 40 should get checked for cataracts at least every 2 years. For those over 65, a yearly eye exam is recommended. 

Managing and Treating Cataracts

Cataract surgery is the only effective treatment. However, other interventions can help manage day-to-day activities during the early stages and before surgery becomes necessary.

Nonsurgical Treatment 

To help slow the development of cataracts and improve vision at home, you can: 

  • Maintain a balanced diet 
  • Use brighter lights while working
  • Wear sunglasses with anti-glare and ultraviolet protection 
  • Protect your eyes from injury
  • Control blood sugar if you have diabetes 
  • Use a magnifying glass for reading and up-close tasks
New Eyeglass Prescription 

Updating your eyeglass or contact prescription helps improve vision and quality of life. It can also slow the progression of cataracts if the lenses have UV blocking properties. 

Cataract Surgery

Cataract surgery is one of the most common, safe, and effective surgeries in the United States.

It’s recommended when symptoms start to interfere with daily life.3 

The lens is replaced with an artificial intraocular lens during cataract surgery, allowing light to reach the retina effectively. There are two types of cataract surgery:

  1. Phacoemulsification. This is the most common type of cataract surgery. It uses ultrasound waves through a small incision to break up the cloudy part of the lens. 
  2. Extracapsular cataract extraction. The hard center of the lens is removed in one piece through a large incision. This method is not common in developed countries as phacoemulsification is safer, faster, and has a shorter recovery time.

If you have cataracts in both eyes, surgery will typically be performed in one eye at a time.  

Cataract Outlook and Prognosis

Living with cataracts can be tolerable until vision loss affects your quality of life. 

Cataract surgery is effective and has a good prognosis, with 9 out of 10 people experiencing improved vision after surgery.1 Because an artificial lens can't develop cataracts, you will not have to worry about them coming back. 

A cloudy layer of scar tissue can form behind the artificial lens, resulting in symptoms similar to cataracts. This development is called posterior capsule opacification and occurs in about 20% of people after cataract surgery. It can be treated with a simple outpatient laser procedure.7

Can You Prevent Cataracts?

While you can’t stop the development of age-related cataracts, there are ways to slow progression and preserve vision, including:

  • Wear sunglasses
  • Quit smoking
  • Maintain a healthy diet
  • Get a dilated eye exam every 2 years after the age of 40, and once a year after age 65
  • Control blood sugar if you have diabetes 

What Can Happen if You Don’t Treat Cataracts? 

If cataracts are left untreated, the clouding of the lens will eventually block all light from entering the eye. This can result in severe vision loss and ultimately blindness. Untreated cataracts are the number one cause of preventable blindness worldwide.4 


Age-related cataracts are a common symptom of aging. Cataracts occur when the usually clear lens (transparent inner part of the eye) becomes cloudy or foggy due to a breakdown in proteins. A cloudy lens results in vision problems such as blurry vision, poor night vision, light sensitivity, and double vision. 

While cataract removal is the only way to eliminate cloudiness, the condition can be tolerated and slowed down in the early stages by wearing sunglasses, using brighter light, quitting smoking, and maintaining a balanced diet. 

To prevent cataract complications, people over age 40 need to get a dilated eye exam at least every 2 years and once a year if they are over 65. 

7 Cited Research Articles
  1. Cataracts.” National Eye Institute. 
  2. How the eye works.” National Eye Institute. 
  3. Cataracts.” University of Rochester Medical Center.
  4. Common eye disorders and diseases.” Centers for Disease Control and Prevention.
  5. Cataracts in children, congenital and acquired.” American Academy of Ophthalmology. 
  6. Do I really need cataract surgery?” Duke Health.
  7. Posterior Capsule Opacification.” University of Michigan Kellogg Eye Center.
Melody Huang is an optometrist and freelance health writer. Through her writing, Dr. Huang enjoys educating patients on how to lead healthier and happier lives. She also has an interest in Eastern medicine practices and learning about integrative medicine. When she’s not working, Dr. Huang loves reviewing new skin care products, trying interesting food recipes, or hanging with her adopted cats.
Amy is a registered nurse who holds a M.S. in nursing from California State University, Sacramento, as well as a B.A. in journalism from California State University, Chico. She is a freelance health writer who brings her deep knowledge of the importance of eye health to Vision Center. Her goal is to combine the worlds of nursing and writing to educate people on common eye conditions and how to prevent vision loss.
Author: Amy Isler  | UPDATED May 24, 2022
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Medical reviewer: Dr. Melody Huang, O.D.
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Dr. Melody Huang, O.D.
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The information provided on VisionCenter.org should not be used in place of actual information provided by a doctor or a specialist.

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