Cataracts - Symptoms, Causes, Diagnosis & Treatment

What are Cataracts?

A cataract is when an area of the eye's lens (clear inner part of the eye) becomes foggy or cloudy. This common eye disorder happens when proteins break down and clump together. 

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.

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. They’re the number one cause of preventable blindness worldwide and the leading cause of vision loss in the United States.⁴

Types of Cataracts 

Age-related cataracts are the most common type. About 17.5% of Americans over 40 have cataracts in one or both eyes. Over half of Americans over the age of 80 have cataracts.¹⁴ 

There are several types of cataracts, including:

Nuclear Cataracts

This type affects the center of the lens. Nuclear cataracts can increase nearsightedness or temporarily improve your reading vision. Over time, the lens becomes more cloudy and dulls your vision.

Cortical Cataracts

These cataracts affect the outer edges of the lens. They begin as opaque streaks or wedges at the edge of the lens. Gradually, these streaks extend toward the center and block light from passing through the lens.

Posterior Subcapsular Cataracts

This type of cataract begins as a small, cloudy area near the back of the lens. A posterior subcapsular cataract sits directly in the path of light. It often causes vision problems, such as:

• Poor reading vision
• Reduced vision in bright light
• Halos or glares around lights at night

These cataracts usually progress faster than other types. 

Congenital Cataracts

These are cataracts you’re born with. They can be present at birth or develop during childhood (pediatric cataracts). Congenital cataracts can be genetic or due to an infection or trauma during pregnancy.

Some congenital cataracts are associated with health conditions, such as:

• Rubella
• Myotonic dystrophy
• Galactosemia
• Neurofibromatosis type 2

Congenital cataracts may not affect vision. When they do, they’re typically removed right away.

Secondary Cataracts

Also known as posterior capsule opacification (PCO), this type sometimes develops after cataract surgery. PCO isn’t an actual cataract. It happens when a layer of scar tissue develops behind the lens implant and clouds your vision.

Secondary cataracts are common and easy to treat. YAG laser capsulotomy is a quick and painless surgery to correct this condition.

Other Types of Cataracts

Other types of cataracts include:

• Traumatic cataracts. Eye injuries and trauma can damage the lens and cause a cataract to form immediately or years later.
• Radiation cataracts. Radiation from the sun (UV) and cancer treatments can cause cataracts.

Symptoms of Cataracts 

Because cataract development progresses over time, vision loss may take years to develop. 

Common cataract symptoms include:

• Cloudy or blurry vision
• Colors are faded, yellowed, or dull
• Trouble seeing at night
• Sensitivity to light
• Double vision 
• Glare or halos around lights
• Frequently needing to change your eyeglass prescription
• Sudden or increased nearsightedness
• Needing brighter light to read 

What Causes Cataracts? 

Age is the most significant factor for developing cataracts, typically starting between 40 and 50.

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 sun exposure (not wearing sunglasses or hats)
• Eye surgery or eye injury
• Radiation and chemotherapy treatment

When to See a Doctor for Cataracts

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)

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. 

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. They may perform several tests, such as:

Visual Acuity Test

This test involves reading letters on an eye chart or viewing the screen with one eye at a time. The letters get progressively smaller. The purpose of a visual acuity test is to determine how well you can see at various distances.  

Slit-lamp Exam

A slit lamp is a lighted microscope your doctor uses to view the structures at the front of your eye. This helps them see abnormalities in your lens, cornea, and iris.

Retinal Exam

Before a retinal exam, your doctor administers dilating eye drops. These make your pupils wider, allowing your doctor to see the back of your eyes (retina). They may use a slit lamp, or an instrument called an ophthalmoscope to examine your eye health and check for signs of cataracts. 

Other Tests

Your eye doctor may perform other exams, such as a glaucoma test, to learn more about your eye health. A glaucoma test checks for increased intraocular pressure.

People over 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 

A stronger prescription for glasses or contact lenses 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 U.S. It’s recommended when symptoms start interfering with daily life.³ 

The lens is replaced with an artificial intraocular lens (IOLs) 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. Laser cataract surgery. This approach uses a femtosecond laser to make an incision in the eye. Then, phacoemulsification occurs.
3. 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 has a good prognosis, with 9 out of 10 people experiencing improved vision afterward.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 lens implant, resulting in a secondary cataract. This is called posterior capsule opacification. It affects about 20% of people after cataract surgery and can be treated with a simple outpatient laser procedure.⁷

Can You Prevent Cataracts?

You can’t stop the development of age-related cataracts. However, there are ways to slow their progression and preserve vision, including:

• Wear sunglasses
• Quit smoking
• Limit alcohol use
• Maintain a healthy diet with plenty of fruits and vegetables
• Get a dilated eye exam every 2 years after the age of 40 and once a year after 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 leading cause of preventable blindness worldwide.⁴ 

Summary

• Age-related cataracts are a common eye condition
• Cataract development occurs when the usually clear lens becomes cloudy
• Lens cloudiness is due to a breakdown and clumping of proteins
• A cloudy lens interferes with the passage of light through your eye
• Cataracts lead to vision problems like blurred vision, poor vision at night, and bright colors that appear dull
• Cataract surgery is the only way to remove cataracts, but nonsurgical treatments can help you manage symptoms
• Cataract surgery is a highly successful surgical procedure