Severe eye pain, sudden blurred vision, redness, rainbow-coloured halos, nausea or vomiting
These symptoms may occur with acute angle closure and a rapid rise in intraocular pressure. Urgent ophthalmic assessment is required; messages and FAQ pages cannot replace an examination.
What happens
What glaucoma is and why it matters
How glaucoma damages the optic nerve, why early disease is often unnoticed, and which symptoms require urgent care.
What is glaucoma?+
The optic nerve carries visual information from the eye to the brain. In glaucoma, some of its nerve fibres are progressively lost. Intraocular pressure is often an important factor when the pressure is too high for a particular eye.
The rate of damage varies between patients. The aim of treatment is therefore not to wait for symptoms, but to detect the disease and keep the risk of progression as low as possible.
Key point
Nerve fibres that have already been lost generally do not recover. Treatment aims to preserve existing visual function and slow or stop further damage.
Is intraocular pressure always raised in glaucoma?+
A pressure level that is safe for one eye may still be too high for another. The ophthalmologist therefore considers not just one number but the optic nerve, OCT, visual field, corneal thickness, anterior chamber angle and changes over time.
Key point
A single “normal” pressure reading does not rule out glaucoma and does not prove that diagnosed glaucoma is stable.
What symptoms occur in the early stages?+
Central visual acuity may remain good for a long time while visual-field defects develop gradually. The other eye can partly compensate, so a person may not notice the change.
At later stages, the visual field may narrow and patients may have more difficulty navigating in dim light, bump into objects at the side, or notice reduced visual quality.
Key point
Good central visual acuity does not exclude glaucoma. Specific tests of the optic nerve and visual field are required.
Who is at increased risk?+
Factors the ophthalmologist considers particularly important
- glaucoma in close relatives;
- raised intraocular pressure;
- age and detected optic-nerve changes;
- a thin central cornea;
- high myopia;
- pseudoexfoliation syndrome;
- an anatomically narrow anterior chamber angle;
- long-term use of corticosteroids.
Key point
A risk factor does not mean glaucoma will inevitably develop, but it is a reason for closer ophthalmic monitoring.
When does glaucoma require urgent care?+
This may be acute closure of the anterior chamber angle with a rapid increase in intraocular pressure. The longer markedly raised pressure persists, the greater the risk of damage to the optic nerve and other ocular structures.
Before examination
- do not wait for the symptoms to resolve on their own;
- do not choose eye drops based on internet advice;
- do not drive if vision has suddenly deteriorated;
- bring a list of your medicines and any ophthalmic records, if available.
Key point
Open-angle glaucoma does not usually cause this pattern. Severe pain and nausea are not reasons to wait for the next routine appointment.
Examination and monitoring
Which tests are useful in glaucoma and why tonometry alone is not enough.
How the diagnosis is assessed
Examination and monitoring
What intraocular pressure tells us, why OCT, visual-field testing and gonioscopy are needed, and how progression is assessed.
Which tests are needed when glaucoma is suspected?+
Baseline assessment commonly includes
- visual acuity and refraction;
- tonometry;
- slit-lamp biomicroscopy;
- examination of the optic disc;
- gonioscopy to assess the anterior chamber angle;
- standard automated perimetry;
- OCT of the retinal nerve fibre layer and ganglion-cell complex.
When indicated, assessment may also include pachymetry, pressure measurements at different times, optic-disc photography and other investigations.
Key point
Not every test is required at every visit. What matters is having reliable results that can be compared over time.
Why is one pressure measurement not enough?+
Tonometry tells us the pressure at a particular moment. OCT and clinical examination assess the structure of the optic nerve, while perimetry assesses its function.
Corneal thickness and biomechanics also affect how pressure readings are interpreted. The ophthalmologist therefore compares pressure with other findings and previous measurements.
Key point
In glaucoma, treatment targets the risk of further optic-nerve damage, not simply a number on the tonometer.
What does optic-nerve OCT show?+
A single colour-coded printout is less useful than comparing good-quality scans over time. The ophthalmologist assesses whether the pattern is compatible with glaucoma and whether there is reliable negative change.
Key point
A red sector on an OCT report does not equal a diagnosis, and a green sector does not guarantee the absence of disease. OCT is interpreted together with examination and visual-field testing.
Why is the visual field tested?+
The test requires concentration and may need to be repeated because of a learning effect or an unreliable first result. A series of comparable tests is more informative than a single printout.
Key point
Visual-field testing and OCT complement one another: one assesses function and the other assesses structure.
What is “target intraocular pressure”?+
The target depends on the stage of disease, starting pressure, age, the condition of the fellow eye, the rate of documented progression and other factors.
If OCT or the visual field continues to worsen, the ophthalmologist may lower the target and intensify treatment even when the pressure numbers appear “reasonable”.
Key point
There is no single safe pressure value for every person with glaucoma.
Eye drops, laser and surgery
How pressure-lowering treatment is selected and when one method is no longer sufficient.
How vision is protected
Eye drops, laser and surgery
Why the central aim of treatment is to lower intraocular pressure to an individual target and preserve visual function for as long as possible.
Can glaucoma be cured completely?+
The main proven way to alter the course of glaucoma is to lower intraocular pressure. Eye drops, laser procedures and surgery are used for this purpose.
Key point
Successful treatment is often not something a patient can feel. Vision may seem unchanged while the disease remains stable.
Do pressure-lowering eye drops need to be used every day?+
Most patients cannot feel changes in intraocular pressure. Missed doses can reduce treatment effectiveness and increase pressure fluctuation.
If the drops cause marked burning, allergy, breathlessness, a slow pulse or other adverse effects, discuss the regimen with your doctor rather than stopping it on your own.
Key point
Do not stop pressure-lowering drops simply because the pressure is lower at a follow-up visit; that lower pressure may be the effect of treatment.
What should I do if I miss a dose?+
For long-term treatment, phone reminders, linking drops to a regular daily activity, and obtaining a replacement bottle before the current one runs out can help.
Key point
If missed doses are frequent, tell your ophthalmologist. The regimen may sometimes be simplified or laser treatment may be discussed.
What is selective laser trabeculoplasty, and can it replace eye drops?+
The magnitude and duration of the effect vary. Some patients can reduce the number of medicines after treatment, while others still require eye drops.
Key point
Laser trabeculoplasty is not suitable for every form of glaucoma. The anterior chamber angle must first be assessed.
When is laser iridotomy performed?+
This is a different procedure and mechanism from laser trabeculoplasty. Indications are determined after gonioscopy and assessment of anterior-segment anatomy.
Key point
Having an iridotomy does not remove the need for future monitoring of intraocular pressure and the optic nerve.
When is glaucoma surgery needed?+
Depending on the type and stage of glaucoma, treatment may include filtering surgery, drainage devices and other surgical approaches. Cyclodestructive laser procedures are used in selected situations.
The choice depends on glaucoma stage, previous surgery, the conjunctiva and cornea, ocular anatomy, coexisting cataract and the degree of pressure reduction required.
Key point
An operation is not selected because it is the “newest”. It is selected according to the likelihood of achieving sufficient, durable pressure reduction with an acceptable risk for that particular eye.
Will vision improve after glaucoma surgery?+
If cataract or another reversible cause of reduced vision is also present, visual function may change after appropriate treatment. However, glaucomatous optic-nerve damage remains irreversible.
Key point
Follow-up continues after successful surgery. The ophthalmologist monitors pressure, the surgical site, the optic nerve and the visual field.
Living with glaucoma and follow-up
How to manage long-term treatment, what everyday activities are generally possible, and why monitoring continues even when you feel well.
Long-term strategy
Living with glaucoma and follow-up
Why glaucoma care is usually long term, how monitoring is organised, and which restrictions actually matter.
Will I need treatment for life?+
Even when pressure is stable and there are no symptoms, the optic nerve and visual field still need periodic assessment. Stability is demonstrated by follow-up findings, not by how the eye feels.
Key point
Having no symptoms is common in glaucoma and is not a reason to stop follow-up.
How often should I be examined?+
Monitoring is usually more frequent after starting a new medicine or after laser or surgical treatment. Once stability has been confirmed, intervals may be longer, but they are set by the treating ophthalmologist.
Key point
OCT and visual-field testing should be repeated often enough to detect clinically meaningful deterioration in time.
Can I exercise, use a computer and fly?+
Regular physical activity is generally beneficial for overall health. Individual restrictions may be needed after surgery, in advanced glaucoma, with marked visual-field loss or with other medical conditions.
After surgery, the surgeon determines when it is safe to return to sport, swimming, sauna use and heavy physical activity.
Key point
Restrictions given after a specific operation take priority over general information on this page.
Should my relatives be examined?+
Family predisposition is particularly relevant to primary open-angle glaucoma. The ophthalmologist determines the appropriate follow-up interval according to age and the overall risk profile.
Key point
A family history increases risk but does not mean every relative will develop glaucoma.
Can glaucoma cause blindness?+
The prognosis depends on the stage at diagnosis, the rate of progression, the pressure achieved with treatment, adherence to therapy and other ocular diseases.
Key point
The practical goal is not to wait until vision worsens, but to check regularly that the disease remains stable.
When should I not wait for the next scheduled visit?+
After recent surgery, increasing pain, a substantial drop in vision, worsening redness or unusual discharge from the eye are particularly concerning.
Key point
If warning symptoms occur, do not rely only on a social-media message or wait for a reply online.
Return to the first section
You can review the basic information again or choose any section from the navigation above.
Do you need an individual assessment of your treatment strategy?
Management depends on the type and stage of glaucoma, the condition of the optic nerve, visual-field findings and the intraocular pressure achieved.
Sources
- Russian Ministry of Health. Clinical guideline “Primary open-angle glaucoma”, 2024. Applicable from 1 January 2025.
- Russian Ministry of Health. Clinical guideline “Primary angle-closure glaucoma”, 2024. Applicable from 1 January 2025.
- Gedde S.J. et al. Primary Open-Angle Glaucoma Preferred Practice Pattern®. Ophthalmology. 2021;128(1):P71–P150.
- European Glaucoma Society. Terminology and Guidelines for Glaucoma, 6th Edition. Br J Ophthalmol. 2025;109(Suppl 1):1–212.
This material is for general information and education. It is not intended for self-diagnosis or for starting, stopping or changing treatment, and it does not replace an in-person ophthalmic consultation. Your individual discharge instructions and your treating doctor’s recommendations take priority.