Does Glaucoma Cause Symptoms? Understanding the Silent Signs and Emergency Warning Symptoms

Author: Dr Val Phua
Estimated reading time: 12–14 minutes

Does Glaucoma Cause Symptoms?

Glaucoma can cause symptoms, but the most common forms usually do not produce noticeable symptoms during their early stages.

Primary open-angle glaucoma and normal-tension glaucoma generally progress:

• Slowly
• Painlessly
• Without visible redness
• Without obvious early blur
• Without affecting central reading vision initially

The National Eye Institute notes that glaucoma symptoms may begin so gradually that patients do not notice them. Vision loss usually begins in the side, or peripheral, field and may remain undetected until the disease becomes more advanced.

This is why glaucoma is often called the silent thief of sight.

However, not every form of glaucoma is silent. Acute angle-closure glaucoma can cause sudden severe symptoms, including intense eye pain, redness, blurred vision and nausea. This is an eye emergency.

Why Can Glaucoma Develop Without Symptoms?

Glaucoma damages the optic nerve gradually.

The optic nerve carries visual information from the retina to the brain. It contains more than one million nerve fibres, many of which contribute to different parts of the visual field.

Early glaucoma often affects small groups of nerve fibres rather than the entire nerve at once.

The patient may not notice the change because:

• The damage develops slowly.
• Early defects may occur away from the centre of vision.
• The other eye may compensate.
• The visual fields of the two eyes overlap.
• The brain may fill in missing visual information.
• Everyday objects continue to appear recognisable.
• Standard reading vision can remain excellent.

A person may therefore have definite optic-nerve damage while still reading the smallest line on the eye chart.

Why Does Glaucoma Usually Affect Side Vision First?

Many forms of glaucoma initially damage nerve fibres responsible for areas outside the central visual field.

This can produce defects such as:

• Nasal steps
• Arcuate blind spots
• Paracentral defects
• Missing areas above or below fixation
• Progressive peripheral constriction

These defects may be small and patchy rather than forming a simple black ring around the vision.

As glaucoma worsens, separate defects may join together. The remaining field may eventually become severely constricted, sometimes described as tunnel vision.

Without treatment, central vision may also be affected in advanced disease.

Why Do Patients Not See a Black Patch?

The visual system does not always represent a glaucomatous blind spot as a clearly defined black area.

Instead, the brain may use:

• Information from the other eye
• Surrounding colours and textures
• Memory of the scene
• Expectations about what should be present

to create an apparently continuous image.

The resulting view may look believable but may omit an object, pedestrian, step or obstacle.

This is one reason patients cannot reliably test themselves by closing one eye and looking around the room.

Can Someone Have Advanced Glaucoma and Still See 6/6?

Yes.

A standard visual-acuity chart measures central, high-contrast vision. It does not adequately measure:

• Peripheral vision
• Contrast sensitivity
• Dark adaptation
• Motion detection
• Glare disability
• The ability to notice unexpected hazards

A patient may retain 6/6 or 20/20 central acuity while having significant peripheral visual-field loss.

Studies have found that contrast sensitivity can be reduced in people with glaucoma even when visual acuity remains 20/40 or better.

A clear reading-vision result does not exclude glaucoma or prove that the patient is safe to drive.

What Symptoms Can Chronic Glaucoma Eventually Cause?

Although early disease is commonly asymptomatic, moderate or advanced glaucoma may affect everyday visual function.

Possible symptoms include:

• Difficulty seeing objects approaching from the side
• Bumping into doorframes or furniture
• Missing steps or kerbs
• Difficulty navigating crowded places
• Trouble finding objects on a cluttered surface
• Difficulty adjusting from bright to dim environments
• Needing more light to read
• Glare
• Hazy or blurred vision
• Reduced contrast
• Difficulty distinguishing boundaries
• Problems driving at night
• Increasing tunnel vision
• Central visual loss in advanced disease

In a study asking glaucoma patients how they actually experienced their vision, the most frequently reported symptoms included needing more light and blurred vision. Patients with greater visual-field loss were more likely to report difficulty seeing objects to the side, viewing as though through dirty glasses and difficulty distinguishing boundaries or colours.

These symptoms are not specific to glaucoma and may also result from cataract, dry eye, retinal disease or an incorrect spectacle prescription. Clinical testing is needed to determine the cause.

Does Primary Open-Angle Glaucoma Cause Symptoms?

Primary open-angle glaucoma is usually silent during its early stages.

The drainage angle remains anatomically open, but aqueous fluid encounters resistance as it leaves the eye. Optic-nerve damage develops gradually.

Most patients do not experience:

• Pain
• Redness
• Sudden blur
• Headache
• A sensation of high pressure

The first noticeable difficulty may occur only after substantial visual-field loss has developed.

Singapore HealthHub states that symptoms of primary open-angle glaucoma are usually gradual and that patients may not notice vision loss until the disease reaches an advanced stage.

Does Normal-Tension Glaucoma Cause Symptoms?

Normal-tension glaucoma is also usually painless and silent.

In this condition, characteristic optic-nerve and visual-field damage develops despite pressure measurements that fall within the usual population range.

Some visual-field defects may occur relatively close to the centre of vision, but the patient may still remain unaware of them.

A normal pressure reading and the absence of symptoms do not exclude normal-tension glaucoma.

Diagnosis requires assessment of:

• Optic-nerve appearance
• Retinal nerve-fibre layer
• Ganglion-cell layer
• Visual field
• Change over time

Does Chronic Angle-Closure Glaucoma Cause Symptoms?

Chronic angle closure may also develop without obvious symptoms.

The peripheral iris gradually blocks or scars parts of the drainage angle. Pressure may increase slowly or intermittently.

Possible symptoms include:

• No symptoms at all
• Mild intermittent blur
• Halos in dim lighting
• Occasional brow ache
• Short episodes of eye discomfort
• Progressive peripheral visual-field loss

The disease may already be advanced before the patient notices a change.

A person can therefore have angle-closure glaucoma without ever experiencing a dramatic acute attack.

What Is Acute Angle-Closure Glaucoma?

Acute angle closure occurs when the drainage angle becomes blocked suddenly.

Aqueous fluid can no longer leave the eye adequately, causing pressure to rise rapidly.

Symptoms may include:

• Severe eye pain
• A red eye
• Sudden blurred vision
• Halos around lights
• Headache
• Brow pain
• Nausea
• Vomiting
• A cloudy-looking cornea
• A poorly reactive or enlarged pupil

The National Eye Institute advises immediate medical assessment for intense eye pain, nausea, redness and blurred vision because these may indicate angle-closure glaucoma.

Singapore HealthHub similarly describes acute angle closure as a sudden rise in pressure causing pain, redness, blurred vision, headache, nausea and vomiting. Urgent treatment is required to protect vision.

Is Acute Angle Closure an Emergency?

Yes.

Acute angle closure can permanently damage the optic nerve if pressure remains very high.

The patient should not:

• Wait until the next working day
• Assume it is conjunctivitis
• Treat it only with painkillers
• Use leftover steroid drops
• Drive to the hospital when vision is impaired
• Wait to see whether vomiting or headache settles

Seek immediate emergency eye care.

Treatment may involve:

• Pressure-lowering eye drops
• Oral or intravenous medication
• Laser peripheral iridotomy
• Laser iridoplasty
• Lens or cataract surgery in selected cases
• Long-term monitoring of both eyes

Can Angle Closure Cause Intermittent Symptoms?

Yes.

The angle may close partially and then reopen.

This can cause episodes of:

• Eye ache
• Brow ache
• Temporary blur
• Coloured halos
• Mild headache
• Symptoms in dim lighting
• Symptoms that improve after sleep or entering a brighter environment

These episodes may be mistaken for:

• Migraine
• Sinus headache
• Eye strain
• Fatigue
• Dry eye

Intermittent symptoms in a person with shallow anterior chambers or other angle-closure risk factors warrant examination.

Does High Eye Pressure Cause a Feeling of Pressure?

Usually not.

Moderately elevated eye pressure commonly causes no sensation at all.

Patients cannot reliably judge eye pressure based on:

• Heaviness around the eye
• Eyelid twitching
• Headache
• Eye strain
• A feeling that the eye is “hard”
• Fatigue after screen use

Very high or rapidly rising pressure can cause pain, blur, corneal swelling, headache or nausea. However, chronic pressure elevation may remain painless for years.

A person can also have glaucoma damage despite normal measured pressure.

Does Glaucoma Cause Headaches?

Chronic open-angle glaucoma usually does not cause headache.

A headache may accompany:

• Acute angle closure
• Rapid pressure elevation
• Severe secondary glaucoma
• Postoperative pressure problems
• Eye inflammation

Most ordinary headaches are not caused by glaucoma.

However, headache accompanied by:

• A painful red eye
• Blurred vision
• Halos
• Nausea
• Vomiting

requires urgent eye assessment.

Does Glaucoma Cause Eye Pain?

Most chronic glaucoma is painless.

Eye pain is more suggestive of:

• Acute angle closure
• Neovascular glaucoma
• Uveitic glaucoma
• Severe pressure elevation
• Corneal disease
• Eye infection
• Postoperative complications
• Another ocular condition

Pain in a known glaucoma patient should not automatically be attributed to their usual chronic disease.

Does Glaucoma Cause Red Eyes?

Ordinary chronic open-angle glaucoma generally does not make the eye look red.

Redness may instead come from:

• Dry eye
• Allergy
• Blepharitis
• Infection
• Uveitis
• Acute angle closure
• Glaucoma eye drops
• Recent laser or surgery

Several glaucoma medications can produce redness, irritation or allergy.

The eye may therefore look red because of the treatment rather than the glaucoma itself.

Persistent redness should still be examined, particularly when accompanied by pain, discharge, light sensitivity or reduced vision.

Can Glaucoma Cause Blurred Vision?

It can, but blurred vision alone is not a reliable glaucoma symptom.

Possible glaucoma-related causes include:

• Advanced optic-nerve damage
• Acute pressure elevation
• Corneal swelling from very high pressure
• Severe angle closure
• Reduced contrast sensitivity
• Loss close to central fixation

More common causes of blur include:

• Refractive error
• Cataract
• Dry eye
• Corneal disease
• Macular disease
• Diabetes
• Medication effects

The cause cannot be identified safely from the symptom alone.

Does Glaucoma Cause Halos Around Lights?

Halos may occur during acute or intermittent angle closure when high pressure causes corneal swelling.

However, halos are also common with:

• Cataract
• Dry eye
• Corneal swelling
• Multifocal intraocular lenses
• Uncorrected astigmatism
• Contact-lens problems

Halos with severe pain, redness, headache or nausea require emergency assessment.

Does Glaucoma Cause Glare or Poor Night Vision?

It can.

Patients with moderate or severe glaucomatous visual-field loss may report:

• Glare
• Difficulty adapting to darkness
• Poor vision in low contrast
• Difficulty driving at night
• Difficulty seeing in rain or dim conditions

A study of patients with glaucomatous field loss found that those with moderate or severe disease more frequently reported glare, dark-adaptation difficulty and driving cessation.

These symptoms can also be caused by cataract, corneal disease and uncorrected refractive error.

Does Glaucoma Cause Floaters or Flashes?

Floaters and flashes are not typical symptoms of glaucoma.

They may be caused by:

• Posterior vitreous detachment
• Retinal tear
• Retinal detachment
• Vitreous bleeding
• Inflammation

A sudden increase in floaters, flashes or a curtain-like shadow requires urgent retinal examination. The National Eye Institute lists these as warning symptoms of retinal detachment rather than glaucoma.

Does Glaucoma Cause Double Vision?

Glaucoma itself does not usually cause double vision.

Double vision may arise from:

• Eye-muscle or nerve problems
• Stroke
• Thyroid eye disease
• Decompensated strabismus
• Significant difference between the eyes
• Certain glaucoma drainage implants
• Advanced asymmetric visual loss
• Other neurological or orbital conditions

New persistent double vision requires assessment.

Does Glaucoma Cause Dizziness?

Dizziness is not a typical symptom of chronic glaucoma.

It may be associated with:

• Severe acute angle closure with nausea
• Systemic side effects of glaucoma medication
• Low blood pressure
• Heart-rate changes
• Neurological or inner-ear disorders
• Difficulty navigating because of advanced visual-field loss

Certain glaucoma drops, particularly beta blockers or alpha agonists, may contribute to dizziness or fatigue in susceptible patients.

Can Glaucoma Affect Colour Vision?

Early glaucoma does not usually cause an obvious colour-vision complaint.

More advanced optic-nerve damage may reduce:

• Contrast
• Colour discrimination
• Boundary recognition
• Visual clarity in complex scenes

A sudden or marked loss of colour vision is unusual for ordinary glaucoma and may suggest another optic-nerve disorder.

Can Glaucoma Make Reading Difficult?

Reading may remain normal for a long time because central vision is often preserved.

Advanced disease may cause difficulty when:

• Damage approaches fixation
• Words disappear within a line
• The patient loses their place
• Contrast sensitivity declines
• Both eyes have central or paracentral defects
• Cataract or dry eye also reduces image quality

Difficulty reading is not a reliable early screening symptom.

Can Glaucoma Affect Walking and Mobility?

Yes, when visual-field loss becomes functionally significant.

Patients may experience:

• Bumping into objects
• Missing obstacles
• Difficulty on stairs
• Hesitation at kerbs
• Difficulty in crowded spaces
• Slower walking
• Greater fall risk
• Difficulty locating objects on the floor

The patient may attribute these problems to ageing, balance or clumsiness rather than to visual-field loss.

Can Glaucoma Affect Driving Before the Patient Notices?

Yes.

Peripheral vision and contrast sensitivity are important for:

• Detecting pedestrians
• Seeing vehicles approaching from the side
• Changing lanes
• Navigating junctions
• Maintaining lane position
• Driving at night
• Responding to hazards

Studies have found poorer driving performance and greater collision risk among glaucoma patients with significant visual-field defects.

A patient may still read the number plate or visual-acuity chart while failing to meet binocular visual-field requirements.

Why Does One Eye Sometimes Hide the Symptoms?

The visual fields of the two eyes overlap.

When one eye has more advanced damage, the better eye may compensate during everyday binocular vision.

The patient may remain unaware until:

• The better eye is covered
• Disease affects both eyes
• A new problem develops in the better eye
• Formal visual-field testing is performed
• Driving or mobility becomes difficult

This is why testing each eye separately is essential.

Can Glaucoma Affect Only One Eye?

Primary glaucoma commonly affects both eyes, although one eye may be much worse.

Secondary glaucoma may affect only one eye when caused by:

• Trauma
• Uveitis
• Steroid exposure
• Retinal vascular disease
• Previous surgery
• Lens abnormalities
• Abnormal iris blood vessels

The absence of symptoms in the other eye does not confirm that it is unaffected.

Do Secondary Glaucomas Cause Symptoms?

Some do.

Neovascular Glaucoma

Neovascular glaucoma may cause:

• Severe pain
• Redness
• Markedly reduced vision
• Very high pressure
• Abnormal blood vessels over the iris

It may occur with severe diabetic retinopathy, retinal-vein occlusion or other retinal ischaemia.

Uveitic Glaucoma

Possible symptoms include:

• Eye pain
• Light sensitivity
• Redness
• Floaters
• Blurred vision

The symptoms may arise from the inflammation, the raised pressure or both.

Traumatic Glaucoma

Pressure elevation following injury may initially cause:

• Pain
• Blur
• Blood inside the eye
• Light sensitivity

However, angle-recession glaucoma may develop years later without symptoms.

Steroid-Induced Glaucoma

Steroid-related pressure elevation is often painless and may be discovered only during pressure monitoring.

Does Pigmentary Glaucoma Cause Symptoms?

Pigment dispersion and pigmentary glaucoma may occasionally cause temporary:

• Blur
• Halos
• Eye ache
• Pressure elevation after vigorous exercise

Many affected patients have no symptoms.

The condition is more commonly recognised in younger or middle-aged myopic adults, but diagnosis depends on examination rather than symptoms alone.

Does Pseudoexfoliative Glaucoma Cause Symptoms?

Pseudoexfoliative glaucoma is often silent until visual-field damage becomes advanced.

Pressure may fluctuate and can sometimes become very high.

Patients may also have:

• Cataract
• Poor pupil dilation
• Weak lens-supporting fibres

These associated findings may cause blur, but the glaucoma itself usually remains painless.

What Symptoms Can Childhood Glaucoma Cause?

Congenital and infantile glaucoma can produce more obvious symptoms than adult open-angle glaucoma.

Possible signs include:

• Excessive tearing
• Light sensitivity
• Eyelid squeezing
• Cloudy corneas
• Enlarged-looking eyes
• Increasing corneal size
• Irritability
• Reduced visual attention

The National Eye Institute recognises congenital glaucoma as a distinct form of the disease.

Older children with juvenile open-angle glaucoma may have few or no symptoms despite very high pressure.

Can Ocular Hypertension Cause Symptoms?

Ocular hypertension means that eye pressure is elevated without definite glaucomatous optic-nerve or visual-field damage.

It is usually asymptomatic.

The patient cannot determine whether ocular hypertension has progressed to glaucoma based on symptoms.

Monitoring may include:

• Eye pressure
• Corneal thickness
• Optic-nerve examination
• OCT
• Visual-field testing
• Assessment of overall risk

Can a Glaucoma Suspect Have Symptoms?

Usually not from the suspicious glaucoma findings themselves.

A glaucoma suspect may have:

• High pressure
• A large optic-nerve cup
• Asymmetry
• A borderline OCT
• A suspicious visual field
• Narrow drainage angles

without experiencing any symptoms.

Symptoms such as blur or discomfort may be caused by a separate condition.

Can Glaucoma Eye Drops Cause Symptoms?

Yes.

Treatment-related symptoms may include:

• Redness
• Burning
• Stinging
• Dryness
• Grittiness
• Blurred vision after application
• Eyelid darkening
• Longer eyelashes
• Eyelid allergy
• Fatigue
• Dizziness
• Slow heart rate
• Breathing difficulty
• Dry mouth

The symptom pattern depends on the medication.

Patients should not stop glaucoma drops without medical advice. An alternative formulation, preservative-free preparation, laser or another treatment may be available.

Can Glaucoma Surgery Cause New Symptoms?

Temporary symptoms after surgery may include:

• Blurred vision
• Redness
• Grittiness
• Watering
• Light sensitivity
• Mild discomfort

Urgent postoperative warning signs include:

• Increasing pain
• Sudden visual reduction
• Marked redness
• Discharge
• Severe headache or nausea
• Trauma to the operated eye
• Redness or pain around a filtering bleb

These symptoms may indicate infection, pressure problems, inflammation or another complication.

Can Symptoms Tell How Severe the Glaucoma Is?

Not reliably.

Some people with advanced disease report few symptoms.

Others with mild glaucoma report considerable blur, glare or discomfort caused partly by:

• Cataract
• Dry eye
• Medication
• Refractive error
• Anxiety or visual awareness

Disease severity should be determined using:

• Optic-nerve examination
• OCT
• Visual-field testing
• Eye-pressure trend
• Documented progression
• Functional assessment

Can I Test My Peripheral Vision at Home?

Home testing may occasionally reveal a major defect, but it cannot exclude glaucoma.

Closing one eye and waving fingers from the side is too crude to detect many early or moderate glaucomatous defects.

A proper visual-field test:

• Presents lights of controlled brightness
• Tests many locations
• Measures sensitivity
• Assesses reliability
• Compares results over time
• Tests each eye separately

No smartphone or home test should replace a comprehensive glaucoma examination.

Why Is an Air-Puff Test Not Enough?

An air-puff test estimates eye pressure.

It does not directly assess:

• Optic-nerve damage
• Retinal nerve-fibre loss
• Visual-field defects
• Drainage-angle anatomy
• Normal-tension glaucoma
• Progression over time

A normal pressure reading does not exclude glaucoma, while a high reading does not automatically prove it.

How Is Glaucoma Detected Before Symptoms Develop?

A glaucoma assessment may include:

Eye-Pressure Measurement

This assesses one major modifiable risk factor.

Optic-Nerve Examination

The ophthalmologist looks for:

• Rim thinning
• Notching
• Cupping
• Disc haemorrhage
• Asymmetry
• Nerve-fibre loss

Optical Coherence Tomography

OCT measures:

• Retinal nerve-fibre layer
• Macular ganglion cells
• Optic-nerve structures

Visual-Field Testing

This identifies functional blind spots and measures their progression.

Gonioscopy

Gonioscopy determines whether the drainage angle is open, narrow or closed.

Corneal-Thickness Measurement

Corneal thickness helps interpret pressure and overall risk.

Guidelines for glaucoma diagnosis and management rely on structured testing and reassessment rather than symptoms alone.

Who Should Be Checked Even Without Symptoms?

Closer assessment is particularly important for people with:

• A family history of glaucoma
• Increasing age
• High eye pressure
• High myopia
• Narrow drainage angles
• Long-sighted eyes with shallow anterior chambers
• Previous eye trauma
• Long-term steroid exposure
• Suspicious optic nerves
• Previous glaucoma in the other eye
• Certain secondary eye conditions

The National Eye Institute recommends comprehensive dilated examinations every one to two years for people at higher risk, with the exact interval determined individually.

Should Everyone Wait Until Age 40?

No.

Although baseline adult eye assessment around age 40 is often useful, earlier examination may be appropriate when there is:

• Strong family history
• Juvenile glaucoma in the family
• Congenital glaucoma
• High myopia
• Significant eye trauma
• Long-term steroid treatment
• Narrow angles
• Childhood or developmental eye abnormalities

Singapore HealthHub encourages regular eye checks after age 40, particularly when a relative has glaucoma.

What Should a Patient Do If Vision Feels Normal?

Continue scheduled follow-up.

Feeling well does not indicate that:

• Pressure is controlled
• OCT is stable
• Visual fields are unchanged
• Drops are no longer required
• Laser or surgery has permanently cured the condition

Glaucoma treatment is preventive. Patients may not feel an immediate benefit because the aim is to preserve vision that would otherwise be lost in the future.

Frequently Asked Questions

Does glaucoma always cause tunnel vision?

No.

Tunnel vision is generally a feature of advanced peripheral visual-field loss.

Early defects are often small, patchy and unnoticed.

Can glaucoma cause sudden blindness?

Chronic open-angle glaucoma usually causes gradual loss.

Acute angle closure, severe secondary glaucoma or vascular complications can cause rapid visual deterioration.

Can glaucoma cause only blurred vision without pain?

It can, but blur has many more common causes.

A complete examination is required.

Can glaucoma cause pain behind the eye?

Chronic open-angle glaucoma usually does not.

Pain behind the eye may have ocular, sinus, neurological or headache-related causes.

Can normal-tension glaucoma cause symptoms?

It is usually silent until visual-field loss becomes significant.

Can pressure of 30 mmHg cause symptoms?

It may cause no symptoms in some patients, especially when elevation is chronic.

A sudden pressure rise to a similar level may be more symptomatic.

The pressure level must be assessed together with the eye’s condition and optic nerve.

Can pressure of 15 mmHg mean I do not have glaucoma?

No.

Some patients develop or progress with pressure measurements in the normal range.

Can I feel my optic nerve being damaged?

No.

Optic-nerve damage itself is not normally painful.

Why do I need glaucoma treatment if I have no symptoms?

Because treatment aims to prevent future irreversible visual loss.

Why do my eyes sting if glaucoma is painless?

The stinging may be caused by:

• Eye drops
• Preservatives
• Dry eye
• Allergy
• Eyelid disease

Does red eye mean my glaucoma is worsening?

Not necessarily.

Redness is commonly caused by medication or ocular-surface disease. Painful redness with blur requires urgent assessment.

Can cataract symptoms be mistaken for glaucoma?

Yes.

Cataract more commonly causes:

• General blur
• Glare
• Halos
• Faded colours
• Poor night vision

Glaucoma more commonly damages the visual field. Both may coexist.

Can glaucoma symptoms improve with new glasses?

Glasses may improve blur caused by refractive error but cannot restore glaucomatous visual-field loss.

Does glaucoma cause flashes?

No, flashes are not typical and may indicate vitreous or retinal traction.

Can one eye hide the other eye’s glaucoma?

Yes.

The better eye and overlapping binocular vision can mask disease in the worse eye.

Can a visual-field defect improve?

Test performance can improve through learning or better concentration.

True nerve-fibre loss is generally irreversible, although a defect caused by cataract or another reversible factor may appear better after that issue is treated.

Is nausea always present in acute angle closure?

No.

A patient may have severe eye pain, redness and blur without vomiting.

Can acute angle closure happen in both eyes?

An acute attack usually affects one eye at a time, but the other eye often has similar narrow-angle anatomy and may also require preventive assessment or treatment.

Can I wait until morning if my eye is painful and red?

Not when pain is accompanied by blur, halos, headache, nausea or vomiting.

Seek emergency eye care.

A Practical Symptom Guide

Usually Silent

• Primary open-angle glaucoma
• Normal-tension glaucoma
• Ocular hypertension
• Glaucoma-suspect findings
• Chronic angle closure
• Steroid-induced pressure elevation
• Early juvenile glaucoma

Symptoms May Appear as Disease Advances

• Reduced side vision
• Bumping into objects
• Trouble on stairs
• Needing more light
• Reduced contrast
• Poor dark adaptation
• Glare
• Difficulty driving
• Tunnel vision
• Central visual loss

Emergency Symptoms

• Severe eye pain
• Red eye
• Sudden blurred vision
• Halos
• Headache
• Nausea
• Vomiting
• Cloudy cornea

These symptoms may indicate acute angle closure and require immediate assessment.

The Bottom Line

Glaucoma can cause symptoms, but the most common chronic forms usually cause no noticeable symptoms during their early stages.

Primary open-angle glaucoma, normal-tension glaucoma and chronic angle closure may progress silently while:

• Central visual acuity remains clear
• The eye remains white
• Pressure causes no sensation
• The other eye compensates
• The brain fills in missing areas

As glaucoma advances, patients may notice:

• Reduced side vision
• Difficulty in dim lighting
• Glare
• Reduced contrast
• Bumping into objects
• Trouble navigating stairs
• Difficulty driving
• Tunnel vision

Acute angle-closure glaucoma is different. It may cause:

• Severe eye pain
• Redness
• Sudden blur
• Halos
• Headache
• Nausea or vomiting

This requires emergency treatment.

Symptoms cannot reliably confirm or exclude glaucoma.

Detection requires:

• Eye-pressure measurement
• Optic-nerve examination
• OCT
• Visual-field testing
• Gonioscopy
• Follow-up for progression

Do not wait for symptoms before checking for glaucoma. By the time chronic glaucoma becomes noticeable, permanent optic-nerve damage may already be advanced.

References

1. National Eye Institute. Glaucoma: Symptoms, Risk Factors, Diagnosis and Treatment. Updated November 2025.
2. Singapore HealthHub and National University Hospital. Glaucoma.
3. National Institute for Health and Care Excellence. Glaucoma: Diagnosis and Management. Guideline NG81. Reviewed March 2025.
4. Hu CX, et al. What Do Patients With Glaucoma See? Visual Symptoms Reported by Patients With Glaucoma. American Journal of the Medical Sciences. 2014.
5. Tam ALC, et al. Self-Perceived Impact of Glaucomatous Visual-Field Loss and Visual Disabilities. Journal of Glaucoma. 2018.
6. Hawkins AS, et al. Comparison of Contrast Sensitivity, Visual Acuity and Humphrey Visual Field Testing in Patients With Glaucoma. Journal of Glaucoma. 2003.
7. Szlyk JP, et al. Driving Performance of Glaucoma Patients Correlates With Peripheral Visual-Field Loss. Journal of Glaucoma. 2005.
8. Lee SSY, et al. Scanning Behaviour and Daytime Driving Performance of Older Adults With Glaucoma. Journal of Glaucoma. 2018.
9. Toh ZH, et al. The Effect of Glaucomatous Visual-Field Defects on Driving Performance. 2025.
10. National Eye Institute. Retinal Detachment: Symptoms and Emergency Warning Signs. Updated November 2025.