Condition Library
Glaucoma
Glaucoma is the condition that most rewards regular eye exams and most punishes skipping them. It produces no pain, no redness, and no blur in its early and middle stages. What it takes is peripheral vision, gradually, and your brain is extremely good at filling in missing peripheral information so that nothing seems wrong.
By the time a person notices glaucoma themselves, a substantial amount of optic nerve has already been permanently lost. That tissue does not come back. Treatment works by stopping further damage, which is why the whole game is finding it early.
Symptoms
- In the common open-angle form, no symptoms at all until advanced
- Gradual loss of peripheral vision, usually unnoticed by the person
- Tunnel vision in advanced disease
- In acute angle-closure glaucoma, which is a medical emergency: sudden severe eye pain, headache, nausea, vomiting, blurred vision and halos around lights
Causes and risk factors
- Raised intraocular pressure, though glaucoma can occur at normal pressure
- Age over sixty
- Family history, which raises risk substantially
- African, Hispanic or Asian ancestry, depending on the type
- Diabetes, which roughly doubles risk
- Severe nearsightedness
- Long-term steroid use
- Previous eye injury or eye surgery
Treatment
- Pressure-lowering eye drops, the usual first-line treatment and highly effective when used consistently
- Laser trabeculoplasty to improve fluid drainage
- Minimally invasive glaucoma surgery, often combined with cataract surgery
- Conventional filtering surgery or drainage implants in advanced cases
- Regular monitoring with pressure checks, optic nerve imaging and visual field testing regardless of treatment
Reducing your risk and protecting what you have
- Have an annual eye exam if you are over sixty, or earlier if you have a family history. This is the only reliable detection method for a disease that produces no symptoms.
- Tell first-degree relatives if you are diagnosed. Family history is one of the strongest risk factors and they should be screened.
- Use prescribed drops every day without gaps, even though you cannot feel any benefit. Adherence is the main determinant of outcome.
- Tell us about any steroid medication, including inhaled, nasal and topical forms, since steroids can raise eye pressure.
- Keep blood pressure and diabetes well controlled, both of which affect blood supply to the optic nerve.
- Treat sudden severe eye pain with headache, nausea and halos around lights as an emergency, which indicates acute angle-closure.
Common misunderstandings about glaucoma
- That you would feel raised eye pressure. You would not. Ordinary open-angle glaucoma produces no sensation whatsoever, and patients are routinely surprised to learn their pressure has been elevated for years. The exception is acute angle-closure glaucoma, which is extremely painful and is a genuine emergency, but that is a different and much less common condition.
- That glaucoma is a disease of old age only. Risk rises sharply with age, and glaucoma occurs in younger adults too, particularly with a family history, high myopia or previous eye trauma. Congenital and juvenile forms exist.
- That good vision means no glaucoma. Central vision, the part you read with, is the last thing glaucoma takes. Someone can have lost a substantial share of their visual field and still read the bottom line of a chart comfortably.
- That once you are on drops, the disease is handled. Drops lower pressure, and pressure is one input. Glaucoma can continue progressing at a pressure that looked adequate, which is why monitoring continues after treatment starts rather than stopping.
How glaucoma is actually diagnosed
There is no single test. Glaucoma is a clinical judgement built from several measurements, which is why a pressure check at a pharmacy is not a glaucoma screen and should not be treated as one.
We measure intraocular pressure, and where readings sit near the borderline we measure at different times of day, because pressure fluctuates through the day and a single morning reading can miss a peak. We examine and photograph the optic nerve head, looking at the ratio of the cup to the disc and at the neuroretinal rim, and we store those images so this year can be compared against last year rather than against a description in a file.
Visual field testing maps the functional loss. Early glaucomatous field defects have characteristic shapes and locations, and finding one changes the diagnosis from suspicion to certainty. Corneal thickness matters too: a thick cornea makes pressure read artificially high and a thin one artificially low, so the same number means different things in different eyes.
Living with a glaucoma diagnosis
The hardest part of glaucoma treatment is adherence, and it is worth naming that directly rather than pretending otherwise. You are asked to use drops every day, indefinitely, to treat something you cannot feel, in order to prevent something you would not notice. Almost nothing about the experience reinforces the behaviour.
Practical things help. Tie the drop to an existing daily habit rather than a time. Keep the bottle where the habit happens. If a drop stings or causes redness that bothers you, tell us, because there are several classes of pressure-lowering medication and switching is straightforward. People stop using drops that are unpleasant, and they usually stop without mentioning it.
Beyond drops, the useful things are keeping your review appointments, telling us about any new medication including inhaled or topical steroids, and letting first-degree relatives know they should be screened, since family history is one of the strongest risk factors we know of.
When to see an optometrist
Book a comprehensive eye exam if you are over sixty, have a family history of glaucoma, or have not been examined in over a year. Go to an emergency room immediately for sudden severe eye pain with nausea and halos around lights.
Related conditions
- Diabetic RetinopathyThe leading cause of new blindness in working-age adults, and completely painless until advanced. Why the annual retinal exam matters.
- CataractsCataracts cloud the lens inside your eye. Symptoms, when surgery is worth having, and how the lens implant decision affects your vision for life.
This page is general educational information, not medical advice or a diagnosis. It is not a substitute for an examination. If you are experiencing sudden vision loss, eye pain or an eye injury, contact us immediately or go to an emergency room.
Glaucoma questions
Can glaucoma be cured?
No, but it can be controlled very effectively. Treatment halts or slows further optic nerve damage. Most people diagnosed and treated in time keep useful vision for life. What cannot be recovered is vision already lost.
Will I know if I have glaucoma?
Almost certainly not, in the common form. That is what makes it dangerous. It is painless, it takes peripheral vision first, and the brain compensates so seamlessly that people routinely lose half their field before noticing.
How is it detected?
Through a comprehensive eye exam: intraocular pressure measurement, direct examination and imaging of the optic nerve, visual field testing, and corneal thickness measurement which affects how pressure readings are interpreted.
Does normal eye pressure mean I do not have glaucoma?
No. Normal-tension glaucoma is well recognised, which is why pressure alone is not a sufficient screen. The appearance of the optic nerve and the visual field matter at least as much.
Book an appointment with a doctor who has time for you
We schedule 2 patients an hour, so your exam is unhurried and your questions get answered. Most patients are seen within a few days.