Cataracts: Symptoms, Causes, Risk Factors, Treatment and Prevention

A cataract is a cloudy area that develops in the normally clear lens of the eye.

The lens sits behind the coloured part of the eye and helps focus light onto the retina at the back of the eye.

When a cataract develops, the lens becomes increasingly cloudy. This interferes with the way light passes through the eye and can gradually affect vision.

A person with cataracts may notice:

• blurry or cloudy vision,
• colours appearing faded,
• difficulty seeing at night,
• glare from lights,
• halos around lights,
• increased sensitivity to bright light,
• frequent changes in glasses prescription,
• or double vision in one eye.

Cataracts usually develop slowly and are particularly common as people get older.

They can occur in one or both eyes, but a cataract cannot spread from one eye to the other.

When cataracts eventually interfere significantly with everyday activities, they can usually be treated very effectively with surgery.

What Is a Cataract?

Inside each eye is a natural lens.

A healthy lens is transparent and helps focus incoming light onto the retina, the light-sensitive tissue at the back of the eye.

As a cataract develops, changes within the lens make it cloudy.

Instead of light passing clearly through the lens, it becomes increasingly scattered.

This can make vision appear as though you are looking through:

• fog,
• haze,
• or a dirty window.

The cloudiness generally increases gradually.

What Causes Cataracts?

Most cataracts are associated with age-related changes in the eye.

As people grow older, proteins and other structures within the lens change and can clump together, producing cloudy areas.

These changes can begin long before someone notices any visual symptoms.

Ageing is therefore the most important general risk factor for cataracts, but it is not the only one.

Are Cataracts Only a Problem After Age 80?

No.

Cataracts are certainly very common in older adults, but they can begin developing considerably earlier.

According to the U.S. National Eye Institute, proteins in the lens begin undergoing age-related changes from around the age of 40.

This does not mean everyone develops noticeable cataract symptoms at 40.

Rather, the likelihood of developing cataracts increases progressively with age.

Can Younger Adults Get Cataracts?

Yes.

Although age-related cataracts are the most common type, younger adults can develop cataracts because of factors such as:

• eye injury,
• diabetes,
• certain medicines,
• radiation exposure,
• previous eye surgery,
• or other medical and eye conditions.

Some people may also have a genetic predisposition.

Can Babies and Children Have Cataracts?

Yes.

Some children are born with cataracts. These are called congenital cataracts.

Others develop cataracts during childhood.

Pediatric cataracts are uncommon but important because a significant cataract can interfere with the normal development of vision.

Possible causes include:

• genetic conditions,
• problems during pregnancy,
• certain childhood illnesses,
• eye injury,
• radiation,
• and certain medicines.

Some pediatric cataracts are small enough that they do not significantly interfere with vision and can be monitored.

Others require prompt treatment to reduce the risk of lasting visual impairment such as amblyopia, sometimes called lazy eye.

What Are the Symptoms of Cataracts?

Early cataracts may produce no noticeable symptoms.

As the cataract progresses, symptoms can include:

• cloudy vision,
• blurry vision,
• hazy vision,
• colours appearing faded or yellowish,
• difficulty seeing at night,
• increased sensitivity to bright lights,
• glare,
• halos around lights,
• difficulty reading,
• needing brighter light to read,
• frequent changes in glasses or contact-lens prescription,
• and double vision in one eye.

Symptoms usually develop gradually.

Why Do Cataracts Make Colours Look Different?

A healthy lens is normally transparent.

As some cataracts develop, the lens can become more yellow or brown.

This can alter colour perception.

Colours may appear:

• less bright,
• less vivid,
• faded,
• or more yellowish.

Some people notice after successful cataract surgery that colours appear brighter than they had realized.

Do Cataracts Cause Double Vision?

They can.

A cataract may cause double vision in the affected eye, sometimes called monocular diplopia.

This means double vision may remain when the other eye is covered.

However, double vision has many possible causes.

New or sudden double vision should not simply be assumed to be a cataract and deserves appropriate medical assessment.

What Is “Second Sight” With Cataracts?

Some people developing certain cataracts temporarily notice that their near vision seems to improve.

For example, a person who previously needed reading glasses may suddenly find it easier to read without them.

This is sometimes informally called “second sight.”

It happens because changes in the lens can temporarily alter the eye's focusing power.

It does not mean the cataract is improving.

The effect is usually temporary, and vision can worsen as the cataract progresses.

Are Cataracts Painful?

Cataracts themselves are generally painless.

Pain is not a typical symptom of an uncomplicated cataract. If significant eye pain develops, another eye condition may be responsible and should be assessed appropriately.

If you develop:

• significant eye pain,
• sudden redness,
• severe headache,
• sudden loss of vision,
• or other acute eye symptoms,

do not assume they are simply caused by a cataract.

Seek urgent medical assessment because another eye condition may be responsible.

Can Cataracts Cause Blindness?

Yes.

Untreated cataracts can eventually cause severe vision impairment and blindness.

Cataracts remain one of the leading causes of vision impairment and blindness globally.

The World Health Organization reported in 2026 that cataract remains among the world's leading causes of vision impairment and blindness.

Importantly, cataract-related visual impairment can often be treated with surgery.

Access to cataract surgery, however, remains unequal around the world.

Are Cataracts Contagious?

No.

Cataracts are not contagious.

You cannot catch a cataract by:

• touching someone,
• sharing household items,
• being near someone with cataracts,
• or looking into someone's eyes.

A cataract also cannot spread from one eye to the other.

However, a person can independently develop cataracts in both eyes.

What Increases the Risk of Cataracts?

Age is the major risk factor, but several other factors can increase the likelihood of developing cataracts or make them develop faster.

These include:

• diabetes,
• smoking,
• excessive alcohol consumption,
• prolonged exposure to sunlight and ultraviolet radiation,
• family history of cataracts,
• previous serious eye injury,
• previous eye surgery,
• radiation treatment,
• and use of certain steroid medicines.

Diabetes and Cataracts

People with diabetes have an increased risk of developing cataracts.

Persistently elevated blood glucose can affect several structures within the eye.

Diabetes can also cause other serious eye diseases, particularly diabetic retinopathy.

People living with diabetes should follow the eye-examination schedule recommended for their individual circumstances.

Maintaining appropriate diabetes management is important for overall health as well as eye health.

Smoking and Cataracts

Smoking is associated with an increased risk of cataracts.

Avoiding tobacco is beneficial not only for the eyes but also for:

• heart health,
• lung health,
• blood vessels,
• and cancer prevention.

If you smoke, stopping is one useful step you can take to protect your long-term health.

Sunlight and UV Exposure

Long-term exposure to ultraviolet radiation from sunlight is associated with cataract development.

When outdoors in strong sunlight, protect your eyes with appropriate sunglasses that provide UV protection.

A wide-brimmed hat can provide additional protection.

Do not look directly at the sun, even while wearing ordinary sunglasses.

Can Steroid Medicines Increase Cataract Risk?

Yes.

Long-term exposure to corticosteroid medicines can increase cataract risk in some people.

Steroids can be given in different forms, including:

• tablets,
• injections,
• eye drops,
• inhalers,
• nasal preparations,
• and topical preparations.

Risk varies according to factors such as:

• the medicine,
• dose,
• route,
• duration of treatment,
• and individual susceptibility.

Do not stop prescribed steroid medication because you are worried about cataracts.

Suddenly stopping some steroids can be dangerous.

Discuss concerns with the healthcare professional who prescribed the medicine.

Can Eye Injuries Cause Cataracts?

Yes.

A significant eye injury can damage the natural lens and cause a traumatic cataract.

The cataract may develop soon after the injury or years later.

People doing activities that can injure the eyes should use suitable protective eyewear.

Examples include certain:

• construction jobs,
• industrial activities,
• home improvement work,
• power-tool use,
• and sports.

Does Exposure to Flames Cause Cataracts?

Ordinary exposure to a household flame is not generally listed as a standard cataract risk factor.

However, intense occupational heat and certain forms of radiation can damage the eyes under particular circumstances.

People working around:

• intense heat,
• welding,
• radiation,
• or hazardous industrial processes

should use appropriate occupational eye protection.

Types of Cataracts

Cataracts can be classified in several ways.

Important categories include:

Age-Related Cataracts

These are the most common cataracts.

They develop as part of age-related changes in the lens.

Traumatic Cataracts

These develop following an eye injury.

They can appear soon after the injury or years later.

Radiation Cataracts

Exposure to certain types of radiation can increase cataract risk.

This can include:

• ultraviolet radiation,
• and radiation used for some medical treatments.

Pediatric Cataracts

These occur in babies or children.

Some are present at birth, while others develop later.

How Are Cataracts Diagnosed?

Cataracts are diagnosed through an eye examination.

An eye-care professional may perform tests that assess:

• visual acuity,
• the eye's lens,
• the retina,
• eye pressure,
• and other structures inside the eye.

A dilated eye examination allows the eye-care professional to examine structures inside the eye more thoroughly.

The examination also helps determine whether another condition is contributing to vision problems.

Do All Cataracts Need Surgery Immediately?

No.

Having a cataract does not automatically mean you need immediate surgery.

Early cataracts may cause only mild visual changes.

Initially, some people can manage their symptoms with:

• updated glasses,
• contact lenses where appropriate,
• brighter lighting,
• magnification,
• and measures to reduce glare.

Regular eye examinations can monitor progression.

Can Eye Drops Remove Cataracts?

At present, standard clinical treatment does not include an eye drop that can reliably dissolve an established cataract and restore a permanently clear natural lens.

Be cautious about products advertised online as:

• cataract-dissolving drops,
• natural cataract cures,
• herbal cataract remedies,
• or alternatives guaranteed to eliminate cataracts without surgery.

Surgery remains the established treatment that removes a visually significant cataract.

When Is Cataract Surgery Recommended?

The decision is generally based on how much the cataract interferes with the person's vision and daily life.

Surgery may be considered when cataracts interfere with activities such as:

• reading,
• driving,
• working,
• watching television,
• recognizing faces,
• navigating safely,
• or performing other important daily tasks.

In some situations, cataract removal may also be needed so an eye specialist can properly examine or treat another condition inside the eye.

What Happens During Cataract Surgery?

During cataract surgery, the surgeon removes the cloudy natural lens.

It is normally replaced with a clear artificial lens called an intraocular lens (IOL).

The artificial lens remains inside the eye and helps focus light.

Modern cataract surgery is usually performed without requiring an overnight hospital stay, although practices vary internationally.

Is Cataract Surgery Effective?

Cataract surgery is one of the most commonly performed surgical procedures and is generally highly effective.

The National Eye Institute reports that approximately 9 out of 10 people who undergo cataract surgery see better afterward.

However, no surgery is completely risk-free.

The expected benefit depends partly on whether the eye also has other conditions such as:

• glaucoma,
• diabetic retinopathy,
• age-related macular degeneration,
• corneal disease,
• or retinal disease.

Your ophthalmologist can discuss the likely benefits and risks for your individual eyes.

What Are the Risks of Cataract Surgery?

Possible complications include:

• infection,
• bleeding,
• inflammation,
• changes in eye pressure,
• retinal detachment,
• swelling,
• and vision problems.

Serious complications are uncommon, but prompt treatment is important when they occur.

Follow all postoperative instructions and attend scheduled follow-up appointments.

Can a Cataract Come Back After Surgery?

The cataract itself does not grow back because the cloudy natural lens has been removed.

However, some people later develop cloudiness in the membrane behind the artificial lens.

This is called posterior capsule opacification (PCO) and is sometimes informally called a “secondary cataract.”

It is not actually a new cataract.

PCO can usually be treated with a brief laser procedure called YAG laser capsulotomy.

Can Cataracts Be Prevented?

It is not currently possible to guarantee that age-related cataracts will never develop.

Ageing is a major factor that cannot be eliminated.

However, some steps may help protect your eyes and reduce modifiable risk factors.

Protect Your Eyes From UV Radiation

When outdoors, use good-quality sunglasses that provide appropriate ultraviolet protection.

A wide-brimmed hat can provide additional shade.

Do Not Smoke

Smoking increases cataract risk and contributes to numerous other diseases.

If you smoke, stopping can benefit your eyes and overall health.

Manage Diabetes

If you have diabetes:

• follow your treatment plan,
• monitor your condition as advised,
• attend recommended health checks,
• and have regular eye examinations.

Good diabetes management is important for protecting vision.

Protect Your Eyes From Injury

Use appropriate protective eyewear when:

• using power tools,
• performing hazardous work,
• playing certain sports,
• handling chemicals,
• or carrying out activities where objects could strike the eyes.

Eat a Nutritious Diet

A balanced eating pattern rich in:

• vegetables,
• fruits,
• whole grains,
• nuts,
• seeds,
• and other nutrient-rich foods

supports overall health.

However, no particular food or dietary supplement has been proven to reverse an established cataract.

Be cautious about supplements marketed as cataract cures.

Have Regular Eye Examinations

Many eye diseases develop gradually.

Regular eye examinations can identify:

• cataracts,
• glaucoma,
• diabetic eye disease,
• refractive errors,
• and other eye problems.

How often you need an examination depends on factors such as:

• age,
• diabetes,
• family history,
• existing eye disease,
• medications,
• and previous eye problems.

Ask an eye-care professional what schedule is appropriate for you.

When Should You See an Eye-Care Professional?

Arrange an eye examination if you notice gradual changes such as:

• increasing blurry or cloudy vision,
• difficulty driving at night,
• glare from headlights,
• halos around lights,
• fading colours,
• difficulty reading,
• or frequent changes in glasses prescription.

These symptoms may be caused by cataracts, but other eye conditions can cause similar changes.

When Are Vision Changes an Emergency?

Cataracts usually cause gradual, rather than sudden, changes in vision.

Seek urgent medical attention for symptoms such as:

• sudden loss of vision,
• sudden severe eye pain,
• sudden onset of double vision,
• a sudden increase in flashes or floaters,
• a curtain or shadow across your vision,
• significant eye injury,
• or severe redness associated with pain or visual loss.

These symptoms may indicate another serious eye condition and should not simply be blamed on cataracts.

The Bottom Line

A cataract is clouding of the eye's natural lens.

Most cataracts develop because of normal age-related changes, although other factors can contribute, including:

• diabetes,
• smoking,
• excessive alcohol use,
• UV exposure,
• eye injury,
• family history,
• radiation,
• previous eye surgery,
• and certain steroid medicines.

Typical symptoms include:

• cloudy or blurry vision,
• faded colours,
• glare,
• halos around lights,
• difficulty seeing at night,
• and sometimes double vision in one eye.

Cataracts are generally painless and not contagious.

Early symptoms can sometimes be managed with updated glasses, brighter lighting and other visual aids.

When a cataract significantly interferes with daily life, surgery is the established treatment. The cloudy natural lens is removed and usually replaced with a clear artificial intraocular lens.

Protecting your eyes from excessive UV exposure and injury, avoiding smoking, managing diabetes and having appropriate eye examinations can all support long-term eye health.

Medical Disclaimer

This article provides general health information for an international audience and is not a substitute for diagnosis, eye examination or individualized treatment from a qualified healthcare professional or eye-care specialist. Cataract screening, surgery eligibility, treatment options and access to eye care vary between countries. Seek urgent medical attention for sudden vision loss, severe eye pain, sudden double vision, new flashes or numerous floaters, significant eye injury or other sudden visual changes.

Sources and Further Reading

National Eye Institute — Cataracts

https://www.nei.nih.gov/eye-health-information/eye-conditions-and-diseases/cataracts

National Eye Institute — Causes of Cataracts

https://www.nei.nih.gov/eye-health-information/eye-conditions-and-diseases/cataracts/causes-cataracts

National Eye Institute — Types of Cataract

https://www.nei.nih.gov/eye-health-information/eye-conditions-and-diseases/cataracts/types-cataract

National Eye Institute — Cataract Surgery

https://www.nei.nih.gov/eye-health-information/eye-conditions-and-diseases/cataracts/cataract-surgery

World Health Organization — Blindness and Vision Impairment

https://www.who.int/news-room/fact-sheets/detail/blindness-and-visual-impairment