What is Glaucoma?
Glaucoma is a group of eye conditions that damage the optic nerve, the “cable” that carries visual information from your eye to your brain. This damage is often, but not always, related to high pressure inside the eye. Over time, glaucoma can slowly steal your side (peripheral) vision, before affecting the central vision. Most people do not notice symptoms until the disease is advanced, which is why glaucoma is often called the “silent thief of sight”.
Damage to the optic nerve is irreversible. Without treatment, glaucoma can lead to permanent vision loss and even blindness. The good news is that with early diagnosis and proper treatment, most patients can preserve useful vision for life.
Types of Glaucoma
Glaucoma is not just one disease. There are several types, and they can behave differently.
Primary open-angle glaucoma
This is the most common type of glaucoma. The drainage angle in the eye looks open, but the fluid does not drain out well. Eye pressure may be raised, and over time this can slowly damage the optic nerve. This is usually painless, and the damage can be advanced before it is detected.
Normal-tension glaucoma
In normal-tension glaucoma, the optic nerve is damaged even though the measured eye pressure is in the normal range. This may be because the optic nerve is more sensitive to effects of eye pressure, or there is poor blood flow to the optic nerve.
Congenital and childhood glaucoma
This rare form is usually genetic, and affects babies and young children. Their eyes may appear unusually large, watery, or cloudy. Parents may notice that their child is sensitive to light, or may have difficulty with vision. Early diagnosis and treatment are very important to protect their sight.
Primary Angle-closure glaucoma
In this type, the drainage angle is very narrow or physically blocked. The rise in eye pressure is typically chronic and painless, just like in POAG. But in some patients, the pressure can can rise quickly and cause sudden symptoms such as eye pain, redness, headache, and blurred vision. This is an eye emergency and needs urgent treatment.
Secondary glaucoma
This type of glaucoma is due to an underlying eye problem (such as injury, inflammation, or an advanced cataract); some other illness; or external factors (such as the use of steroid medications). Treating the underlying problem (removing the cataract, stopping the steroids) can improve the eye pressure and sometimes even stop the glaucoma from progressing.
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Difficulty seeing in dim light
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Blurred or patchy vision
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Bumping into objects on one side
What are the symptoms of Glaucoma?
Many types of glaucoma cause no pain, and have no obvious symptoms in the early stages. Your central vision may remain clear while your side vision slowly becomes restricted. Because the change is so gradual, most people do not realise they have glaucoma until a lot of damage has already occurred.
In more advanced stages, some people may notice:
Symptoms of Acute
Angle-Closure Glaucoma
One exception is acute angle-close glaucoma, which occurs when there is sudden blocking of the drainage angles, and eye pressure rises rapidly.
You may have sudden symptoms such as severe eye pain and redness, headache, nausea, halos around lights, or a sudden drop in vision.
This is an eye emergency and needs immediate treatment with your eye doctor or at the nearest Emergency Department.
How is Glaucoma diagnosed?
Once glaucoma damages the optic nerve, the lost vision cannot be recovered. However, early detection and treatment can slow or stop further damage.
Regular comprehensive eye examinations are the best way to detect glaucoma before you notice any vision changes. These tests help determine if you have the condition, and how advanced it may be.
Tonometry
Measuring your eye pressure to detect levels that may damage the optic nerve.
Slit Lamp Exam
Examining the front part of your eye for any signs of narrowing or blockage of the eye's drainage angles.
Optic Nerve Exam
Examining the optic nerve with the slit lamp to detect patients at risk of glaucoma.
Cornea Thickness
Cornea thickness can have a small effect on the accuracy of eye pressure measurements
OCT Scans
Optical coherence tomography (OCT) scans are performed to detect and quantify any ongoing damage to the optic nerve
Visual Field Test
Testing your side (peripheral) and central vision to determine how much of the vision has been affected by glaucoma.
Your doctor will use these comprehensive results to discuss your eye health and tailor a specific management plan for you.
How is Glaucoma treated?
The goal of glaucoma treatment is to lower the pressure inside the eye to a level that is safe for your optic nerve. Every patient's treatment is customised, depending on the type and severity of the glaucoma.
Glaucoma eye drops
Most patients start treatment with prescription eye drops. These help reduce eye pressure by decreasing the amount of fluid produced in the eye or improving its drainage.
It is very important to use your drops daily and as prescribed, even if your vision seems normal. Stopping your eyedrops for a period of time means that the eye pressure can rise again, and result in further harm to your optic nerve.
Laser treatment
Laser procedures can help fluid drain out of the eye more effectively or open up a narrow drainage angle. Common laser treatments for glaucoma include:
- Laser trabeculoplasty – improves drainage in open-angle glaucoma.
- Laser iridotomy – creates a tiny opening in the iris (coloured part of the eye) to relieve or prevent angle-closure glaucoma.
- Cyclophotocoagulation – reduces fluid production in more advanced or difficult-to-control cases.
Glaucoma surgery
If drops and/or laser are not enough to control the eye pressure, surgery may be recommended. Surgical options include:
- Trabeculectomy – creates a new drainage channel for fluid to leave the eye.
- Glaucoma drainage implants (tubes or shunts) – small devices placed in the eye to help drain fluid.
- Minimally invasive glaucoma surgery (MIGS) – newer procedures that use tiny devices or instruments to lower eye pressure, often combined with cataract surgery.
Living Well with Glaucoma
Being diagnosed with glaucoma can feel worrying, but many people continue to live normal, active, and independent lives.
Key points to remember include:
- Make time for your regular follow-up appointments.
- Take your eye drops exactly as prescribed.
- Bring along your eye drops even while you are travelling.
- Inform your doctor if you have trouble remembering or using your drops.
- Tell your eye doctor about all other medications you are taking.