What Causes Cataracts? Common Causes and Risk Factors

Reviewed by Dr. Audrey Tai, Athena Eye Care — Mission Viejo, Orange County, CA

Quick answer: Cataracts develop when proteins in the eye's natural lens break down and clump together, clouding vision. The most common cause is aging, but cataracts can also be triggered by eye trauma, diabetes, congenital factors, high blood pressure, smoking, and excessive alcohol consumption. Many of these risk factors are modifiable, meaning lifestyle changes can meaningfully reduce your risk.

▶ Hear directly from our patients about their cataract surgery experience

What Causes Cataracts?

Cataracts are a condition where the eye's normally clear lens becomes cloudy, leading to blurred or distorted vision — often described as looking through a foggy window. This happens because proteins in the lens break down and form clumps that block light from passing through to the retina.

There are several causes of cataracts, ranging from age-related changes to environmental and lifestyle factors. Understanding these causes can help you take proactive steps to protect your long-term vision.

→ Learn more about the three types of cataracts

The 7 Most Common Causes of Cataracts

1. Aging (Age-Related Cataracts)

Aging is by far the most common cause of cataracts. As we get older, natural proteins in the lens of the eye begin to break down and clump together, creating the cloudy areas we recognize as cataracts. Over time, these cataracts grow larger, leading to significant vision impairment — and, if left untreated, total vision loss.

The good news: age-related cataracts are highly treatable. Cataract surgery removes the clouded natural lens and replaces it with a clear artificial intraocular lens (IOL), restoring vision in the vast majority of patients.

→ Understanding Your Intraocular Lens Options

2. Traumatic Cataracts

Eye injuries can cause cataracts to form — sometimes immediately, sometimes years after the original trauma. Common causes include:

• Blunt force trauma to the eye or head
• Penetrating eye injuries
• Chemical burns
• Electric shock
• Radiation exposure

Traumatic cataracts often develop in younger patients than typical age-related cataracts and may require specialized surgical planning.

3. Diabetes

People with diabetes are approximately 60% more likely to develop cataracts than those without diabetes. Two mechanisms drive this elevated risk:

• Elevated glucose levels in the eye's aqueous humor cause swelling and protein damage in the lens
• The lens converts excess glucose into sorbitol, a sugar alcohol that accumulates and further damages lens proteins

Tight blood sugar control reduces — though does not eliminate — this added cataract risk.

4. Congenital Cataracts

Although cataracts are most often associated with aging, some infants are born with congenital cataracts. These can result from:

• Genetic predisposition or inherited conditions
• Infections during pregnancy (e.g., measles, rubella, toxoplasmosis)
• Metabolic disorders such as galactosemia
• Trauma or inflammation before or during birth

Congenital cataracts require prompt evaluation by a pediatric ophthalmologist, as untreated cases can interfere with normal visual development.

5. High Blood Pressure (Hypertension)

Chronic high blood pressure can lead to inflammation and oxidative stress in the eye, increasing cataract risk. High blood pressure is also linked to other serious eye conditions, including glaucoma and macular degeneration, making cardiovascular health an important component of long-term vision care.

6. Smoking

Smokers have a significantly higher risk of developing cataracts than non-smokers. Toxins in cigarette smoke produce oxidative stress that damages the cells of the eye's lens — the same mechanism that drives many of the long-term harms of smoking elsewhere in the body. Quitting smoking is one of the most effective steps you can take to reduce cataract risk.

7. Excessive Alcohol Consumption

Heavy alcohol use is also linked to a higher cataract risk. Alcohol metabolism produces free radicals that damage proteins in the eye, accelerating the clouding of the lens. Moderation, as defined by national health guidelines, is recommended for both eye and overall health.

Other Risk Factors

In addition to the seven primary causes above, the following may increase cataract risk:

• Long-term use of corticosteroids (oral, inhaled, or topical)
• Previous eye surgery for other conditions
• Ultraviolet (UV) radiation from prolonged unprotected sun exposure
• Severe nearsightedness (high myopia)
• Certain medications including some used in psychiatric and dermatologic care

Many of these risk factors are modifiable, which means lifestyle adjustments can meaningfully change your trajectory.

How to Reduce Your Risk of Cataracts

While age-related cataracts can't be entirely prevented, several evidence-based steps can reduce your risk and slow progression:

• Wear UV-protective sunglasses outdoors year-round
• Maintain a diet rich in antioxidants — leafy greens, colorful fruits and vegetables, and foods high in vitamins C and E
• Quit smoking
• Manage diabetes and blood pressure with regular medical care
• Limit alcohol consumption
• Schedule routine comprehensive eye exams — especially after age 50

Recognizing the signs of cataracts early is also extremely important.

→ Recognizing the Early Signs of Cataracts → What Happens if Cataracts Are Left Untreated

Frequently Asked Questions About Cataract Causes

Are cataracts genetic?

There is a hereditary component — family history can increase your risk — but most age-related cataracts result from a combination of aging and lifestyle factors, not pure genetics. Some rare congenital cataracts are inherited.

Can cataracts be prevented?

Age-related cataracts can't be fully prevented, but you can reduce your risk and slow progression by avoiding smoking, controlling diabetes and blood pressure, eating an antioxidant-rich diet, and protecting your eyes from UV radiation.

At what age do cataracts typically start?

Lens proteins begin to change as early as your 40s, but most clinically significant cataracts develop in the 60s, 70s, and beyond. By age 80, more than half of Americans have cataracts or have had cataract surgery.

Does staring at screens cause cataracts?

No. There's no credible evidence that screen use causes cataracts. Screens can cause eye strain and dry eye, but those are separate conditions.

Can cataracts come back after surgery?

True cataracts cannot return once the natural lens has been replaced with an artificial IOL. However, a condition called posterior capsular opacification ("secondary cataract") can develop months or years later. It's easily treated with a quick in-office laser procedure (YAG capsulotomy).

What You Can Do

If you're experiencing symptoms such as blurred vision, glare, or difficulty seeing at night, it's important to consult an eye doctor promptly. Cataracts are highly treatable, and cataract surgery is one of the safest and most commonly performed procedures in the world.

📞 Call Athena Eye Care: (949) 889-2020
🌐 Visit: www.athenaeyecare.com

Let Dr. Audrey Tai at Athena Eye Care help you restore your vision and your quality of life — serving Mission Viejo, San Juan Capistrano, Laguna Niguel, Dana Point, San Clemente, and the wider Orange County, California community.

Know Your Coverage

Because insurance policies vary greatly, it's crucial to verify the details of your coverage before scheduling cataract surgery. For assistance determining your benefits or to learn more about cataract surgery, contact Athena Eye Care.

→ Read more about Cataract Surgery and Insurance Coverage

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