Sudden and severe pain in the eyes can signal glaucoma - a serious eye condition. But often, glaucoma progresses with no symptoms at all -- so regular eye checks are important to keep this silent thief of sight at bay.
What is Glaucoma?
Glaucoma is an eye disease, where the high fluid pressure within your eye damages the delicate fibres of the optic nerve. These delicate nerve fibres are responsible for carrying visual impulses from your eye to the brain. This damage is irreversible and can lead to blindness in advanced cases. Glaucoma accounts for 40% of blindness in Singapore.
Vision affected by glaucoma
What causes Glaucoma?
The excessive build-up of pressure in your eye occurs because of an imbalance between fluid production and its drainage out of the eye. There are different types of glaucoma.
Primary open-angle glaucoma accounts for the majority of the cases. It affects the elderly and those who are middle-aged. The glaucoma progresses slowly and painlessly, so you may not notice that your vision is deteriorating. Peripheral and night vision will be affected before your central reading vision.
Optic nerve damaged by glaucoma
Acute angle closure glaucoma usually affects elderly and middle-age Chinese women in Singapore. The onset of this form of glaucoma is sudden with the eye pressure rising rapidly and dramatically in the eye. This results in eye pain and redness, headache and nausea. Other accompanying symptoms include blurred vision and seeing of coloured rings around lights.
Chronic angle-closure glaucoma progresses gradually and often goes unnoticed for a long time. It is caused by the progressive blockage of drainage channels in the eye causing a slow, prolonged rise in eye pressure.
Secondary glaucoma is usually the result of a pre-existing eye condition such as inflammation, severe diabetic eye disease and tumors. Previous eye injury or surgery as well as long term steroid use may also cause secondary glaucoma.
How do I know if I have Glaucoma?
The disease can develop slowly and you may not be aware of the gradual loss of sight until very late in the disease when your vision is seriously affected.
This is an interactive illustration demonstrating the loss of the field of vision at different stages of glaucoma severity.
Please use the mouse, click and hold down the blue arrow.
As you begin to slide the blue arrow towards the right, you will see a magnified view of a normal healthy optic nerve in the right box.
As this optic nerve is normal and healthy, the field of vision shown on the left box is normal.
However once a patient develops glaucoma, there is progressive optic nerve damage from the loss of healthy nerve fibres (see right box image), thus leading to progressive loss of the visual field.
The patient will experience this as a progressive 'tunnelling' of vision or constriction of the field of vision (see left box image).
This is illustrated by sliding the blue arrow between the points indicating "Early Glaucoma" and "Advanced Glaucoma".
What puts me at risk of Glaucoma?
• Age – your risk increases once you are over 50 years old. In Singapore, glaucoma affects about
3 percent of those aged over 50. This risk increases with age; the percentage of people aged
over 70 affected by glaucoma is 10 percent
• Chronic diseases – you are at an increased risk of certain types of glaucoma if you have diabetes
and high blood pressure
• Ethnicity – Asians and Afro-caribbeans are more susceptible to certain types of glaucoma than
• Eye injuries
• Extreme nearsightedness or shortsightedness
• Family history of glaucoma
• Use of steroids
What can I do to prevent Glaucoma?
Most risk factors of glaucoma such as age, hereditary risk and race cannot be prevented. If you have a family history of glaucoma or are taking medications that put you at risk, regular eye examinations are essential (Find out the importance of an eye examination). Early diagnosis is the key to prevent blindness as glaucoma nerve damage is irreversible.