Introduction

Glaucoma accounts for 40% of blindness in Singapore. It is an eye disease where the fluid pressure within the eyeball is too high and damages the optic nerve, which carries visual impulses from the eye to the brain. This pressure build-up occurs because of an imbalance between the production and drainage of fluid within the eyeball.

Glaucoma is damaging to sight because the raised pressure can injure the delicate nerve fibres contained in the retina and the optic nerve at the back of the eyeball.

The vast majority of cases develop slowly, and the patient is normally not aware of the gradual loss of sight until very late in the disease when vision is seriously affected.

Different Types Of Glaucoma

Primary Open-Angle Glaucoma
This accounts for the majority of glaucoma cases in most countries. It affects the elderly and middle-aged. Relatives of people with glaucoma have a higher risk of having the disease as it may be inherited. The glaucoma progresses slowly and is often not noticed by the patient, as there are usually no symptoms like pain or redness. Peripheral (ie side) vision and night vision are gradually affected first. Central reading vision is affected only very late.

Acute Angle Closure
This form of glaucoma usually affects middle-aged and elderly Chinese women in Singapore. Due to a sudden blockage of the fluid outflow channel, there is a rapid, drastic rise in the fluid pressure within the eye. This results in eye pain, redness, headache, nausea and vomiting. Blurred vision and coloured rings around lights are accompanying symptoms.

Chronic Angle-Closure Glaucoma
Like Primary Open-Angle Glaucoma, this form of glaucoma progresses gradually, and often goes unnoticed for a long time. It results from progressive blockage of the drainage channels of the eyeball, and a slow prolonged rise in pressure.

Secondary Glaucoma
This is sometimes caused by inflammation of the eyeball or when a cataract becomes too advanced and swollen. Other causes are tumours, injuries and surgery to the eyeball.

Treatment

The earlier glaucoma is diagnosed, the greater the chances of success in preventing visual loss. Assessment for glaucoma is easily carried out in the clinic and is painless. It includes the measurement of eyeball pressure, optic nerve examination, an assessment of the fluid drainage channels of the eyeball, and a test to chart the area of the vision that each eye can see (Visual Fields).

Although glaucoma cannot be cured, in most cases it can be successfully controlled. The treatment depends on the type of glaucoma. It may be in the form of medication (eg eyedrops), laser therapy or surgery. Your doctor will discuss with you the best treatment in your case.

It is important to note that the success of treatment for glaucoma is measured by the stability of the condition, which only your eye doctor can determine. The degree of sharpness of your vision does not indicate how well the glaucoma is controlled. Patients should therefore continue with regular check-ups with your eye specialist to ensure that everything is well, and to detect early worsening of the glaucoma to prevent visual loss.