Cataract: Symptoms, Causes, Types and Treatment

Author: Dr Val Phua
Estimated reading time: 20 minutes

A cataract is a clouding of the eye’s natural lens.

The natural lens is normally clear and helps focus light onto the retina at the back of the eye. When the lens becomes cloudy, light is scattered or blocked before it reaches the retina, causing vision to become blurred, hazy, faded or affected by glare.

Cataracts are particularly common with increasing age, but they can also occur in younger adults and children because of diabetes, medication, inflammation, trauma, previous eye surgery, radiation exposure or inherited and congenital conditions.

A cataract may affect:

• One eye or both eyes
• One part of the lens or several parts
• Distance vision
• Near vision
• Colour perception
• Contrast
• Night driving
• Sensitivity to glare

Cataracts usually develop gradually and do not cause pain. Early symptoms may sometimes be managed with a new glasses prescription, brighter lighting or changes to daily activities. Once the cataract significantly interferes with useful vision, surgery is the only established method of removing it.

Modern cataract surgery removes the cloudy lens and replaces it with a clear artificial intraocular lens, or IOL. The operation can improve vision substantially when the cataract is the main reason for the visual difficulty, but the final result also depends on the health of the cornea, retina, optic nerve and the rest of the eye.

The Quick Answer

What Is a Cataract?

A cataract is any loss of clarity within the natural crystalline lens of the eye.

The clouding may be:

• Mild and localised
• Diffuse
• Central
• Peripheral
• Present from birth
• Acquired later in life

A cataract does not spread from one eye to the other, although both eyes commonly develop cataracts at different rates.

What Are the Most Common Symptoms?

Cataracts may cause:

• Gradually blurred or cloudy vision
• Glare from sunlight or headlights
• Halos around lights
• Poor night vision
• Faded or yellowed colours
• Reduced contrast
• Frequent changes in glasses prescription
• Monocular double vision
• Increasing short-sightedness
• Difficulty reading
• Difficulty recognising faces
• Difficulty driving safely

Early cataracts may cause no noticeable symptoms.

Are Cataracts Painful?

Cataracts themselves usually do not cause:

• Eye pain
• Significant redness
• Discharge
• Sudden flashes or floaters
• A curtain over the vision

These symptoms may indicate another eye condition and should not be attributed automatically to a cataract.

Can Cataracts Be Treated With Eyedrops?

No eyedrop, vitamin, medicine or natural remedy has been proven to remove an established cataract in routine clinical care.

New glasses, better lighting and anti-glare measures may improve function temporarily, but surgery remains the only established treatment that physically removes the cloudy lens.

When Should a Cataract Be Removed?

A cataract should generally be considered for surgery when it affects activities that matter to the patient, such as:

• Driving
• Reading
• Working
• Watching television
• Using a computer
• Recognising faces
• Walking safely
• Managing medications
• Performing hobbies
• Remaining independent

The cataract does not need to become “ripe” or completely white before surgery. Current guidance bases the decision primarily on functional impairment, visual requirements, ocular health and the balance of benefits and risks.

Understanding the Natural Lens

Where Is the Lens?

The natural lens sits behind:

• The cornea
• The iris
• The pupil

Light travels through the cornea and pupil before passing through the lens.

The lens then focuses the light onto the retina.

What Does a Healthy Lens Do?

A clear lens:

• Transmits light
• Helps focus a sharp image
• Contributes to the eye’s overall prescription
• Changes shape to help younger people focus at near

With age, the lens becomes:

• Less flexible
• Thicker
• More yellow
• Less transparent

Loss of flexibility causes presbyopia, while loss of transparency produces a cataract.

How Does a Cataract Blur Vision?

A cataract can:

• Scatter light
• Block light
• Reduce contrast
• Create glare
• Alter the eye’s prescription
• Reduce colour transmission
• Produce several competing images

A patient may therefore have significant difficulty in real-life situations despite still being able to read relatively small high-contrast letters in the clinic.

Common Symptoms of Cataracts

Gradually Blurred Vision

The most typical symptom is painless, progressive blur.

Patients may describe vision as:

• Cloudy
• Smoky
• Misty
• Foggy
• Less sharp
• As though looking through a dirty window

The blur may affect one eye more than the other.

Glare

Glare may occur when light scatters inside the cloudy lens.

Common situations include:

• Bright sunlight
• Oncoming headlights
• Streetlights
• Reflective surfaces
• Indoor spotlights
• Wet roads at night

Glare may be more troublesome than ordinary eye-chart blur.

Halos Around Lights

A patient may notice:

• Rings around headlights
• A glow around streetlights
• Star-shaped rays
• Smearing around illuminated signs

Halos can also be caused by dry eye, corneal disease, glaucoma or problems after cataract surgery, so examination is important.

Poor Night Vision

Night driving may become difficult because cataracts reduce contrast and increase the effect of glare.

Patients may find it harder to see:

• Pedestrians
• Lane markings
• Kerbs
• Road signs
• Vehicles in the distance

Faded or Yellowed Colours

A cataract may absorb and scatter shorter wavelengths of light.

Patients may notice that:

• White objects appear cream or yellow
• Blues seem less vivid
• Colours look dull
• The operated eye later sees colours as brighter than the unoperated eye

Frequent Prescription Changes

The refractive power of the lens may change as the cataract progresses.

This can result in:

• Increasing short-sightedness
• Increasing astigmatism
• Fluctuating spectacle prescriptions
• Temporary improvement in near vision
• Reduced distance vision

Second Sight

Some patients with a nuclear cataract temporarily become more short-sighted and find that they can read without glasses again.

This is sometimes called second sight.

It does not mean that the cataract is improving. Distance vision usually becomes worse, and near vision may decline again as the cataract progresses.

Monocular Double Vision

A cataract may produce two or more images in one eye.

This is called monocular diplopia.

It generally remains present when the unaffected eye is covered and may result from irregular light refraction within the cloudy lens.

True binocular double vision that disappears when either eye is covered may have another neurological or eye-alignment cause.

Needing Brighter Light

Patients may require:

• A stronger reading lamp
• More light in the kitchen
• Brighter phone or computer screens
• Better lighting on stairs

Very bright light may eventually worsen glare even though dim lighting makes detail difficult to see.

Reduced Contrast

A patient may still see black letters on a white chart but struggle with:

• Grey steps
• Pale print
• Facial features
• Fog
• Rain
• Low-light objects

Reduced contrast can affect safety before central visual acuity becomes severely impaired.

Types of Age-Related Cataract

Nuclear Sclerotic Cataract

A nuclear cataract affects the centre, or nucleus, of the lens.

It commonly causes:

• Gradual distance blur
• Increasing short-sightedness
• Temporary improvement in unaided near vision
• Yellowing or browning of colours
• Reduced contrast

Nuclear cataracts often progress gradually over several years.

Cortical Cataract

A cortical cataract affects the outer layers of the lens.

It often begins as:

• White spokes
• Wedge-shaped opacities
• Peripheral lens changes

As the opacities extend towards the centre, they may cause:

• Glare
• Halos
• Difficulty in bright light
• Variable blur
• Reduced night-driving ability

Posterior Subcapsular Cataract

A posterior subcapsular cataract develops near the back surface of the lens, close to the visual axis.

It may cause:

• Disproportionate glare
• Difficulty reading
• Poor vision in bright light
• Rapid visual deterioration
• Halos
• Reduced contrast

Because of its central location, a relatively small posterior subcapsular cataract can cause substantial symptoms.

Posterior subcapsular cataracts are associated with factors including corticosteroid use, diabetes, inflammation and previous eye treatment.

Mixed Cataract

Many patients have more than one type of lens opacity.

For example, the same eye may have:

• Nuclear sclerosis
• Cortical spokes
• Posterior subcapsular changes

The overall symptoms depend on the location and density of each component.

Cataracts in Younger People

Diabetic Cataract

People with diabetes may develop cataracts:

• At a younger age
• More rapidly
• In association with changing blood-glucose levels

Diabetes can also affect the retina, macula and ocular surface. A preoperative retinal assessment is therefore important because blurred vision may not be caused by the cataract alone.

Steroid-Related Cataract

Corticosteroids may be prescribed as:

• Tablets
• Inhalers
• Nasal sprays
• Skin creams
• Eyedrops
• Injections

Long-term or high-dose steroid exposure can increase the risk of posterior subcapsular cataract.

Do not stop medically necessary steroids without discussing the risks and alternatives with the prescribing doctor.

Traumatic Cataract

Blunt or penetrating eye injuries can damage the lens.

A traumatic cataract may:

• Appear immediately
• Develop months or years later
• Be associated with lens instability
• Occur with iris, corneal, retinal or optic-nerve injury

Traumatic cataract surgery may be more complex than routine age-related cataract surgery because the capsule and the supporting zonules may have been damaged.

Uveitic or Inflammatory Cataract

Repeated or chronic inflammation inside the eye may accelerate cataract formation.

The inflammation may be caused by:

• Autoimmune disease
• Infection
• Previous trauma
• An unexplained inflammatory condition

Steroid treatment used to control inflammation may also contribute.

Cataract surgery is generally planned when the inflammation has been adequately controlled.

Radiation-Related Cataract

Radiation exposure involving the eye or upper body can increase cataract risk.

This may include:

• Therapeutic radiation
• Occupational exposure
• Repeated high-dose exposure

Appropriate eye protection and medical monitoring are important when relevant.

Cataract After Previous Eye Surgery

Cataracts may develop more rapidly after procedures such as:

• Vitrectomy
• Retinal-detachment surgery
• Glaucoma surgery
• Intraocular inflammatory procedures

The cataract operation may require additional planning because of altered anatomy or the underlying eye condition.

Congenital and Childhood Cataracts

What Is a Congenital Cataract?

A congenital cataract is present at birth or develops during early childhood.

It may affect:

• One eye
• Both eyes
• Part of the lens
• The entire lens

Causes may include:

• Genetic conditions
• Metabolic disorders
• Infections during pregnancy
• Developmental abnormalities
• An unknown cause

Why Are Childhood Cataracts Different?

A young child’s visual system is still developing.

A visually significant cataract can prevent the brain from learning to use the affected eye, causing amblyopia.

Early recognition and treatment may therefore be time-sensitive.

Treatment may involve:

• Cataract surgery
• Glasses
• Contact lenses
• Intraocular-lens implantation in selected cases
• Patching
• Long-term amblyopia treatment

Children require prolonged follow-up because of risks including glaucoma, visual-axis opacification and changing refractive needs.

Signs in a Child

Possible warning signs include:

• A white pupil
• An absent or abnormal red reflex
• Eye misalignment
• Poor visual attention
• Shaking eye movements
• One eye appearing different
• Difficulty following objects

A white pupil in a child requires prompt ophthalmic examination because conditions other than cataract, including serious retinal disease, can cause the same appearance.

Risk Factors for Cataracts

Increasing Age

Ageing is the most important risk factor.

Changes in lens proteins, oxidative balance, water content and lens structure gradually reduce transparency.

Diabetes

Poorly controlled diabetes can accelerate cataract development and may cause changing prescriptions when blood-glucose levels fluctuate.

Smoking

Smoking is associated with a greater risk of cataract and contributes to oxidative stress.

Stopping smoking benefits both ocular and general health.

Corticosteroid Medication

Both systemic and ocular corticosteroids can increase cataract risk, particularly posterior subcapsular cataract.

Eye Injury

Blunt or penetrating trauma may directly damage the lens and its supporting structures.

Previous Eye Inflammation or Surgery

Uveitis, vitrectomy and other intraocular procedures can accelerate cataract formation.

Ultraviolet and Radiation Exposure

Substantial cumulative ultraviolet or radiation exposure is associated with cataract risk.

UV-blocking sunglasses, hats and occupational eye protection are sensible protective measures.

Family History and Genetic Conditions

Inherited susceptibility may contribute to both childhood and adult cataracts.

Certain genetic and systemic conditions are also associated with earlier cataract development.

High Myopia

Highly myopic eyes may develop certain cataract types earlier and can require additional retinal and biometric assessment before surgery.

Can Cataracts Be Prevented?

Prevention Is Not Guaranteed

Most age-related cataracts cannot be completely prevented.

However, reducing avoidable risk may delay cataract formation or support overall eye health.

Stop Smoking

Smoking cessation is one of the most useful modifiable steps.

Protect the Eyes From Injury

Use suitable protective eyewear during:

• Power-tool use
• Metalwork
• Construction
• Racquet sports
• Ball sports
• Contact sports
• Chemical handling

Protect Against Excessive UV Exposure

Use sunglasses that provide appropriate ultraviolet protection and consider a brimmed hat outdoors.

Manage Diabetes

Stable blood-glucose control supports both lens and retinal health.

Use Steroids Appropriately

Steroid medication should be used:

• For a clear medical indication
• At an appropriate dose
• For the necessary duration
• With monitoring when long-term treatment is required

Eat a Balanced Diet

A diet rich in:

• Vegetables
• Fruit
• Whole grains
• Nuts
• Fish
• Healthy fats

supports general health.

No specific food or supplement has been proven to dissolve an established cataract.

How Is a Cataract Diagnosed?

Symptom History

The ophthalmologist may ask about:

• Blur
• Glare
• Halos
• Night driving
• Reading
• Colour changes
• Occupation
• Hobbies
• Falls
• Previous glasses changes
• Medication
• Diabetes
• Trauma
• Previous eye surgery

Visual-Acuity Testing

Vision is measured:

• Without correction
• With current glasses
• After refraction

The best-corrected acuity helps determine how much blur is caused by prescription and how much may remain because of cataract or other eye disease.

Refraction

Refraction measures:

• Short-sightedness
• Long-sightedness
• Astigmatism
• Reading addition

A new prescription may improve early cataract symptoms temporarily.

Slit-Lamp Examination

A slit lamp allows the ophthalmologist to examine:

• The cornea
• Anterior chamber
• Iris
• Natural lens
• Location and density of the cataract

Dilated Retinal Examination

Dilating drops enlarge the pupil so the doctor can examine:

• Retina
• Macula
• Optic nerve
• Retinal blood vessels
• Peripheral retina

The examination helps determine whether another condition may limit the visual outcome.

Eye-Pressure Measurement

Eye pressure is checked because glaucoma may coexist with cataract.

Glare or Contrast Testing

When symptoms are disproportionate to ordinary visual acuity, additional tests may assess:

• Glare disability
• Contrast sensitivity
• Functional vision

Optical Coherence Tomography

Macular OCT may be performed when there is concern about:

• Epiretinal membrane
• Macular degeneration
• Diabetic macular disease
• Vitreomacular traction
• Macular oedema

Subtle macular disease may affect the expected improvement after cataract surgery.

Biometry

Before surgery, biometry measures the eye to calculate the appropriate IOL power.

Measurements may include:

• Eye length
• Corneal curvature
• Anterior-chamber depth
• Lens thickness
• Corneal astigmatism

Accurate measurements are essential because cataract surgery also changes the eye’s prescription.

Corneal Topography or Tomography

Additional corneal imaging may be required for:

• Astigmatism
• Keratoconus
• Previous LASIK or PRK
• Irregular corneal shape
• Premium-lens planning

When Is the Right Time for Surgery?

Functional Difficulty Matters More Than the Cataract Grade Alone

A cataract should not be removed simply because it is visible.

Equally, surgery should not be denied merely because the patient can still read a certain line on an eye chart.

The decision should consider:

• Driving safety
• Reading ability
• Work requirements
• Glare
• Contrast
• Vision in the other eye
• Independence
• Risk of falls
• General health
• Expected benefit
• Surgical risk

Guidelines emphasise shared decision-making based on the patient’s functional needs rather than waiting for an arbitrary level of visual acuity or cataract “maturity.”

You Do Not Need to Wait Until the Cataract Is Ripe

The idea of waiting until a cataract becomes completely mature comes from an earlier era of cataract surgery.

Modern surgery is often performed once the visual impairment justifies the risks and inconvenience.

Reasons Not to Delay Excessively

A very advanced cataract may:

• Make the operation technically more difficult
• Require more ultrasound energy
• Prevent examination of the retina
• Reduce independence
• Affect driving
• Increase visual imbalance
• Contribute to falls or reduced quality of life

Cataract surgery is associated with improved visual function and quality of life when visual impairment is caused by cataract.

Reasons to Wait

Observation may be appropriate when:

• Symptoms are mild
• Daily activities are unaffected
• Glasses provide satisfactory vision
• The expected benefit is limited by another eye condition
• Medical or ocular problems need optimisation
• The patient does not yet feel ready

Non-Surgical Management

Updated Glasses

A new prescription may improve early cataract-related blur.

Frequent changes may be required if the cataract continues altering the eye’s focusing power.

Better Lighting

Helpful adjustments may include:

• Brighter reading lights
• Directed task lighting
• Improved stair lighting
• Higher-contrast household markings

Anti-Glare Measures

Patients may benefit from:

• A visor
• UV-protective sunglasses
• Avoiding direct bright lights
• Reducing night driving
• Keeping windscreens and spectacles clean

Magnification

Reading may be assisted temporarily with:

• Magnifying lenses
• Larger print
• Electronic enlargement
• Increased screen font size

These measures do not stop cataract progression.

Cataract Surgery

What Happens During Surgery?

In modern phacoemulsification surgery:

1. The eye is anaesthetised.
2. Small corneal incisions are created.
3. A circular opening is made in the front lens capsule.
4. The cataract is divided using ultrasound energy.
5. The lens material is removed.
6. The remaining capsule is cleaned.
7. A folded artificial lens is inserted.
8. The lens unfolds inside the capsular bag.
9. The small wound is checked and usually seals without stitches.

The cloudy natural lens does not grow back after it has been removed.

Is the Patient Awake?

Most adult cataract surgery is performed using:

• Numbing eyedrops
• Local anaesthesia
• Mild sedation when required

The patient is generally awake but should not feel sharp pain.

How Long Does It Take?

The surgical portion is commonly brief, although the total visit is longer because of:

• Registration
• Pupil dilation
• Preparation
• Anaesthesia
• Recovery
• Discharge instructions

Complex cataracts may require additional time.

Is Cataract Surgery an Outpatient Procedure?

Most routine cataract operations are performed as day surgery, allowing the patient to return home the same day.

Types of Intraocular Lens

Monofocal IOL

A monofocal lens has one principal focal distance.

It may be targeted for:

• Distance
• Intermediate
• Near

When both eyes are targeted for distance, reading glasses are generally needed.

Toric IOL

A toric lens corrects regular corneal astigmatism.

It may reduce dependence on distance glasses but does not automatically provide near vision.

Enhanced Monofocal IOL

An enhanced monofocal lens aims to preserve good distance vision while extending some functional intermediate range.

Reading glasses are commonly still required for fine print.

Extended-Depth-of-Focus IOL

An EDOF lens aims to provide:

• Distance vision
• Strong intermediate vision
• Some functional near vision

Reading glasses may still be required.

Multifocal or Trifocal IOL

A multifocal or trifocal lens provides more than one focal range.

It may increase spectacle independence for:

• Distance
• Computer work
• Reading

Possible trade-offs include:

• Halos
• Glare
• Starbursts
• Reduced low-light contrast
• Neuroadaptation

Evidence generally shows stronger unaided near vision with trifocal lenses, while EDOF and enhanced monofocal lenses emphasise intermediate function.

Monovision

In monovision:

• One eye is targeted mainly for distance.
• The other is targeted for intermediate or near vision.

This can reduce glasses dependence but may affect depth perception or visual balance in some patients.

Choosing an IOL

The Best Lens Is Individual

The choice depends on:

• Corneal health
• Astigmatism
• Macular health
• Optic-nerve health
• Previous LASIK or PRK
• Night-driving requirements
• Reading priorities
• Occupation
• Hobbies
• Tolerance for halos
• Willingness to use glasses
• Cost
• Expectations

The most expensive or newest lens is not automatically the most appropriate.

Premium Lenses Require Careful Selection

Multifocal and some EDOF lenses generally require:

• Healthy maculae
• Healthy optic nerves
• Regular corneal optics
• Stable dry eye
• Accurate astigmatism management
• Realistic expectations

A monofocal or toric monofocal lens may provide better overall quality in an eye with significant retinal, optic-nerve or corneal disease.

What Results Can Be Expected?

Most Patients See Better

When cataract is the main cause of visual impairment and surgery is uncomplicated, most patients experience significant improvement.

The National Eye Institute reports that approximately 9 in 10 patients see better after cataract surgery.

Vision May Still Be Limited

Possible causes of reduced postoperative vision include:

• Residual prescription
• Astigmatism
• Macular degeneration
• Diabetic retinopathy
• Glaucoma
• Corneal disease
• Amblyopia
• Surgical complications
• Posterior capsule opacification

Real-world studies identify refractive error, ocular comorbidity and postoperative complications as important reasons for suboptimal visual outcomes.

Glasses May Still Be Required

The need for glasses depends on:

• IOL type
• Refractive target
• Astigmatism
• Biometric accuracy
• Working distance
• Ocular health

Cataract surgery aims to reduce dependence on glasses but cannot guarantee complete spectacle independence.

Recovery After Cataract Surgery

Early Vision

Vision may initially be:

• Blurred
• Bright
• Slightly hazy
• Sensitive to light
• Different in colour

Improvement may occur over days, although complete stabilisation can take longer.

Common Temporary Symptoms

Patients may experience:

• Mild grittiness
• Watering
• Mild redness
• Fluctuating vision
• Dryness
• Light sensitivity
• A small blood spot on the white of the eye

Dry Eye After Surgery

Cataract surgery can temporarily worsen tear-film instability and dry-eye symptoms, particularly in patients who already have meibomian-gland dysfunction or ocular-surface disease.

Postoperative Drops

Medication may include:

• Antibiotic drops
• Steroid drops
• Non-steroidal anti-inflammatory drops
• Lubricating drops
• Eye-pressure medication when needed

Use the prescribed medication exactly as directed.

Activity Restrictions

The patient may temporarily be advised to avoid:

• Eye rubbing
• Dirty water exposure
• Swimming
• Heavy exertion
• Contact sports
• Eye makeup

Instructions vary according to the surgeon, procedure and the health of the eye.

Possible Complications

Residual Refractive Error

The final prescription may differ from the intended target.

Management may include:

• Glasses
• Contact lenses
• Laser enhancement
• IOL repositioning
• IOL exchange in selected cases

Dry Eye

Dry eye may cause:

• Fluctuating vision
• Burning
• Grittiness
• Glare
• Poor reading comfort

Corneal Swelling

Corneal oedema may cause:

• Hazy vision
• Halos
• Morning blur

It usually improves, but prolonged swelling requires assessment.

Raised Eye Pressure

Eye pressure may rise because of:

• Retained viscoelastic
• Inflammation
• Steroid response
• Pre-existing glaucoma

Cystoid Macular Oedema

Inflammatory fluid may accumulate in the macula.

Symptoms may include:

• Central blur
• Distortion
• Reduced contrast
• Delayed visual improvement

Posterior Capsule Opacification

The thin capsule behind the IOL may become cloudy months or years later.

This is called:

• Posterior capsule opacification
• PCO
• An after-cataract
• Sometimes inaccurately, a secondary cataract

It can cause:

• Blurred vision
• Glare
• Halos
• Reduced contrast

PCO is one of the most common long-term postoperative problems and can usually be treated with YAG laser capsulotomy.

Retinal Tear or Detachment

Symptoms may include:

• New flashes
• A sudden shower of floaters
• A curtain
• A missing area of peripheral vision

These require urgent assessment.

Endophthalmitis

Endophthalmitis is a rare but serious infection inside the eye.

Possible symptoms include:

• Increasing pain
• Increasing redness
• Worsening vision
• Marked light sensitivity
• Eyelid swelling
• Discharge

Prompt treatment is essential.

Posterior Capsule Rupture

The capsule may tear during surgery.

This can require:

• Vitrectomy
• A different IOL position
• Additional treatment
• Closer retinal monitoring

IOL Decentration, Dislocation or Toric Rotation

A lens that moves from its intended position may cause:

• Blur
• Ghosting
• Astigmatism
• Unequal vision
• Glare

Repositioning or exchange may occasionally be required.

Warning Signs After Surgery

Seek urgent ophthalmic assessment for:

• Significant or worsening pain
• Sudden visual loss
• Increasing redness
• Increasing light sensitivity
• Thick discharge
• New flashes
• A sudden shower of floaters
• A curtain or shadow
• Nausea and vomiting with eye pain
• Trauma to the operated eye

Mild grittiness and fluctuating vision can occur during normal recovery, but symptoms that are severe or progressively worsening should not be ignored.

Cataract Surgery and Other Eye Conditions

Macular Degeneration

Cataract surgery may improve cataract-related blur, but the final central vision depends on macular function.

A monofocal lens is often preferred when macular disease is significant.

Diabetic Retinopathy

Diabetic patients may require:

• Macular OCT
• Retinal treatment
• Stable glucose control
• Closer monitoring for macular oedema

Glaucoma

Cataract surgery may be performed alone or combined with a glaucoma procedure.

Lens choice should consider:

• Visual-field loss
• Contrast sensitivity
• Future glaucoma surgery
• Optic-nerve health

Fuchs Endothelial Dystrophy

Patients with reduced corneal endothelial function may have a greater risk of prolonged corneal swelling.

Some may require combined or staged corneal transplantation.

Previous LASIK or PRK

Previous laser vision correction makes IOL-power calculations less predictable.

Additional measurements and specialised formulas may be required.

High Myopia

Highly myopic eyes may have:

• Greater retinal risk
• Longer eye length
• More challenging IOL calculations
• A greater chance of pre-existing retinal disease

Common Myths

“A Cataract Must Be Ripe Before Surgery”

False.

Surgery is generally considered when the cataract interferes meaningfully with function and the expected benefit outweighs the risk.

“Cataracts Grow Back”

The removed natural lens does not grow back.

Posterior capsule opacification may later make vision cloudy but is a different condition.

“Eyedrops Can Dissolve Cataracts”

No approved eyedrop has been shown to remove an established cataract in routine clinical practice.

“Cataract Surgery Guarantees No Glasses”

No.

Glasses use depends on the IOL, refractive target, astigmatism and accuracy of the result.

“A Premium Lens Is Always Better”

No.

The best lens is the one that matches the eye’s health and the patient’s priorities.

“Cataract Surgery Is Completely Risk-Free”

No operation is risk-free.

Cataract surgery is commonly performed and generally successful, but uncommon sight-threatening complications can occur.

Frequently Asked Questions

Is a Cataract a Film Over the Eye?

No.

A cataract forms inside the natural lens behind the iris.

It cannot be wiped or washed away.

Can Cataracts Affect Only One Eye?

Yes.

Both eyes commonly develop cataracts, but one may progress much faster.

Can a Cataract Cause Sudden Vision Loss?

Most cataracts cause gradual visual change.

Sudden loss of vision requires urgent examination for another cause, such as:

• Retinal detachment
• Retinal-vessel occlusion
• Macular bleeding
• Acute glaucoma
• Optic-nerve disease

Can Cataracts Cause Headaches?

Cataracts do not usually directly cause headaches.

Eye strain from blurred or changing vision may contribute to discomfort, but persistent headache requires broader assessment.

Can Cataracts Cause Floaters?

No.

Floaters arise from the vitreous cavity rather than the lens.

New flashes or a sudden increase in floaters requires retinal examination.

Can Cataracts Be Removed From Both Eyes at Once?

Same-day bilateral cataract surgery may be appropriate in selected patients and healthcare systems.

Many patients undergo sequential surgery on separate days.

The choice depends on:

• Ocular risk
• General health
• Surgeon and facility protocols
• Patient preference
• Anaesthetic considerations

Will I Be Awake During Surgery?

Usually, yes.

The eye is numbed, and sedation may be given.

Is Cataract Surgery Painful?

Most patients experience:

• Pressure
• Touch
• Bright lights
• Fluid around the eye

rather than sharp pain.

Tell the surgical team immediately if you experience significant discomfort.

Will I Need Stitches?

Most modern small-incision cataract operations do not require stitches.

A stitch may be used if the wound requires additional security.

How Long Does the Artificial Lens Last?

The IOL is intended to remain permanently inside the eye.

It does not require routine replacement.

Can the Artificial Lens Be Changed?

An IOL can sometimes be exchanged, but this is another intraocular procedure with additional risks.

Can I Still Develop a Cataract After Lens Replacement?

No cataract can form within an artificial lens in the same way as in the natural lens.

Posterior capsule opacification may develop behind it.

Can Cataract Surgery Improve Reading Vision?

It depends on the lens strategy.

A distance-targeted monofocal lens generally requires reading glasses.

Monovision, EDOF or multifocal strategies may reduce near-spectacle dependence.

What Happens if I Do Not Have Surgery?

The cataract may:

• Remain stable
• Progress slowly
• Progress more rapidly
• Interfere increasingly with daily life

In advanced cases, it may eventually cause severe visual impairment.

When to Arrange an Eye Examination

Arrange a routine examination if you notice:

• Gradually blurred vision
• Glare
• Faded colours
• Poor night driving
• Frequent spectacle changes
• Increasing dependence on light
• Difficulty reading

Arrange urgent assessment for:

• Sudden loss of vision
• Eye pain
• Marked redness
• New flashes or floaters
• A curtain over the vision
• New double vision
• A white pupil in a child
• An eye injury

A Cataract Assessment Checklist

Symptoms to Mention

• Distance blur
• Reading difficulty
• Glare
• Halos
• Poor night vision
• Colour changes
• Double vision in one eye
• Frequent glasses changes
• Falls or mobility concerns

Medical and Eye History

• Diabetes
• Steroid use
• Previous LASIK
• Previous retinal surgery
• Glaucoma
• Macular degeneration
• Eye trauma
• Uveitis
• Contact-lens wear

Lifestyle Priorities

• Night driving
• Computer distance
• Reading
• Sports
• Fine hobbies
• Willingness to wear glasses
• Tolerance for halos

Questions to Ask

• Is the cataract the main cause of my symptoms?
• Is there any retinal or optic-nerve disease?
• When should surgery be considered?
• What refractive target is planned?
• Do I have astigmatism?
• Which IOL is most suitable?
• Which activities will still require glasses?
• What are my individual surgical risks?
• What is the expected recovery?

The Bottom Line

A cataract is a clouding of the eye’s natural lens.

It commonly causes:

• Gradual painless blur
• Glare
• Halos
• Poor night vision
• Faded colours
• Reduced contrast
• Frequent prescription changes

Ageing is the most common cause, but cataracts may also be associated with:

• Diabetes
• Steroids
• Trauma
• Eye inflammation
• Previous surgery
• Radiation
• Congenital or genetic conditions

Early symptoms may be managed temporarily with:

• Updated glasses
• Brighter lighting
• Magnification
• Anti-glare measures

Surgery is the only established way to remove the cloudy lens.

The correct time for surgery is not when the cataract becomes “ripe.” It is when the visual difficulty affects activities that matter to the patient and the expected benefits outweigh the risks.

Modern cataract surgery usually provides substantial visual improvement, but the final result depends on:

• The health of the cornea
• The retina
• The optic nerve
• The accuracy of the IOL calculation
• Astigmatism
• The selected lens
• The course of healing

The most important decision is therefore not simply whether a cataract is present.

It is whether the cataract is sufficiently responsible for the patient’s visual difficulty—and which surgical and lens strategy offers the most useful and realistic visual outcome.

References

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2. National Institute for Health and Care Excellence. Cataracts in Adults: Management. NICE Guideline NG77. London: NICE; 2017. PMID: 29106797. Surveillance updated 2025.
3. American Academy of Ophthalmology. Cataract in the Adult Eye Preferred Practice Pattern. San Francisco: American Academy of Ophthalmology; 2021. Summary benchmarks updated 2025.
4. National Eye Institute. Cataracts. National Institutes of Health. Updated November 26, 2025.
5. Han X, Zhang J, Liu Z, Tan X, Jin G, He M, Luo L, Liu Y. Real-world visual outcomes of cataract surgery based on population-based studies: a systematic review. Br J Ophthalmol. 2023;107(8):1056–1065. doi:10.1136/bjophthalmol-2021-320997. PMID: 35410876.
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10. Donachie PHJ, Sparrow JM, Johnston RL. The Royal College of Ophthalmologists’ National Ophthalmology Database study of cataract surgery: Report 9, risk factors for posterior capsule opacification. Eye. 2023;37(8):1633–1639. PMID: 36002508.
11. Saba A, et al. Infection prevention and control factors associated with post-cataract surgery endophthalmitis: a review of the literature from 2010–2023. Infect Prev Pract. 2024. PMID: 39188789.
12. Al-Mohtaseb Z, Steigleman WA, Pantanelli SM, et al. Toric monofocal intraocular lenses for the correction of astigmatism during cataract surgery: a report by the American Academy of Ophthalmology. Ophthalmology. 2024;131(3):383–392. doi:10.1016/j.ophtha.2023.10.010. PMID: 38149945.