Glaucoma
What is glaucoma?
Glaucoma is a group of conditions in which the optic nerve, the cable joining the eye to the brain, is progressively damaged. Raised pressure inside the eye is the main treatable risk factor. Damage usually starts in the outer field of vision and is painless, so it is often found only on an eye examination. Treatment lowers pressure to slow further loss.
How the eye keeps its pressure
The eye continuously makes a clear fluid called aqueous humour, which nourishes the front of the eye and then drains away through a filter at the angle where the iris meets the cornea. Pressure inside the eye depends on the balance between how much fluid is made and how easily it drains.
If drainage becomes less efficient, pressure rises. The optic nerve head is the most vulnerable structure, and over months and years its nerve fibres can be lost.
The main types
- Primary open angle glaucoma, the commonest form, where the drainage angle looks open but does not work well. It is painless and gradual.
- Angle closure glaucoma, where the drainage angle becomes physically blocked. An acute attack causes severe pain, redness, blurred vision and sometimes vomiting, and is an emergency.
- Normal tension glaucoma, where typical optic nerve damage occurs even though pressure readings sit in the normal range.
- Secondary glaucoma, caused by another problem such as injury, inflammation, advanced cataract, diabetes related changes or steroid medication.
- Congenital and childhood glaucoma, which is uncommon but important, and may show as large cloudy eyes, watering and light sensitivity in a baby.
Why it is usually silent
In open angle glaucoma vision is lost from the periphery inwards. The brain compensates by filling in the missing areas using the other eye and its own prediction, so people often notice nothing until a large amount of field is gone. Central vision, and therefore the ability to read a letter chart, can stay normal until late.
What can be done
Lowering eye pressure is the only treatment shown to slow glaucoma. That is achieved with eye drops, laser treatment or surgery, chosen according to the type of glaucoma, the pressure level, how much damage has occurred and how well you can manage drops. Damage already present does not reverse, so the goal is protecting what you have.
When to seek urgent assessment
- Sudden severe eye pain with redness, blurred vision, haloes around lights, headache or vomiting, which may be acute angle closure
- A rapid change in vision in an eye already known to have glaucoma
Frequently asked questions
- Is glaucoma the same as cataract?
- No. Cataract is clouding of the lens and surgery can restore that clarity. Glaucoma damages the optic nerve and that damage cannot be reversed, although further loss can be slowed.
- Can young people get glaucoma?
- Yes. It is far more common with age, but it occurs in young adults, children and rarely in babies, particularly where there is a family history.
Concerned about these symptoms?
Arrange an eye examination with our consultant ophthalmologist in Garki, Abuja.
Care at Standard Eye
Related answers
- What are the symptoms of glaucoma?
- What is eye pressure, and what is a normal reading?
- What does glaucoma screening involve?
- Which tests are used to diagnose glaucoma?
Return to all glaucoma answers.