Glaucoma is a specific pattern of optic nerve damage and visual field loss caused by a number of different eye diseases that can affect the eye. Most, but not all of these diseases, are characterized by abnormally high pressure within the eye created by the fluid (aqueous fluid) in one or both eyes. When this pressure (called the intraocular pressure) remains elevated over a period of time, damage occurs to the delicate optic nerve. Currently, damage from glaucoma cannot be reversed. If left untreated, blindness often results. Glaucoma usually affects both eyes.
This disease causes `silent blindness´ because it strikes without obvious symptoms. Therefore, the person with glaucoma is usually unaware of it until serious loss of vision has occurred. In fact, half of those suffering damage from glaucoma do not know it.
Glaucoma is a leading cause of blindness in people over forty. Early detection and treatment of glaucoma are the only way to prevent visual impairment and blindness.
In Malaysia, some form of glaucoma affects about 1 in 2000 people.
Are there different types of glaucoma?
Yes. There are two main types.
The most common is chronic glaucoma (chronic = slow) in which the eye pressure rises very slowly and there is no pain to show there is a problem, but the field of vision gradually becomes impaired.
Acute glaucoma (acute = sudden) is much more common in Asian eyes. This happens when there is a sudden and complete blockage to the flow of aqueous fluid in the eye. This can be quite painful and will cause permanent damage to vision if not treated promptly.
There are however other types of glaucoma that is beyond the scope of this discussion.
Who is at Risk?
There are a few predisposing factors related to this disease which tend to put some people at greater risk:
- People over the age of 45
- People who have a family history of glaucoma
- People with abnormally high intraocular pressure (IOP)
- Myopia (nearsightedness)
- Regular, long-term steroid/cortisone use
- A previous eye injury
How is chronic glaucoma detected?
In the early stages, a person will not experience any symptoms. The early visual changes are very slight, usually only affecting peripheral vision. The centre of the visual field is last affected, so that eventually it appears like the patient is looking through a long tube, in the late stages, the so-called 'tunnel vision'. In time even this sight would be lost.
It is therefore, important to have our eyes checked regularly, because early detection and treatment of glaucoma are the only way to prevent visual impairment and blindness. In Malaysia, screening tests for glaucoma is generally done by ophthalmologists (eye doctors). Please consult the chart below to determine how often you should visit your eye doctor for a comprehensive glaucoma examination.