Glaucoma

The picture of Glaucoma.

Glaucoma accounts for 40% of blindness in Singapore.

It is an eye condition in which pressure within the eyeball is increased due to an imbalance between the production and drainage of fluid resulting in damage to the optic nerve that carries visual impulses from the eye to the brain.

It develops gradually and the patient may not even be aware of the gradual loss of vision until very late in the disease.

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Glaucoma affects vision because the raised pressure can injure the delicate nerve fibres in the retina and the optic nerve at the back of the eyeball.

Types of Glaucoma

Primary Open-Angle Glaucoma affects peripheral (side) vision and night vision first and, in later stages, central reading vision is affected.

Acute Angle Closure Glaucoma is due to sudden obstruction to drainage channels in the eyeball and presents with eye pain, redness, headache, nausea and vomiting. Blurred vision and coloured rings around lights may be accompanying symptoms.

Chronic Angle-Closure Glaucoma progresses gradually and results from progressive blockage of the drainage channels of the eyeball and a slow prolonged rise in pressure.

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

Risk factors

Glaucoma can affect anyone but persons at higher risk include those with:

• A family history of Glaucoma
• Diabetes
• Migraine
• Short sightedness (myopia)
• Eye injuries
• Blood pressure
• Past or present use of cortisone drugs (steroids)

Diagnosis

Regular eye examinations are the best way to detect glaucoma early. The following tests are used to detect glaucoma.

• Measurement of eye ball pressure (tonometry)
• Fundal assessment with an ophthalmoscope to check the optic nerve
• Visual field assessment to test the sensitivity of the side vision which is affected earlier than central vision

Treatment

Glaucoma cannot be cured but can be controlled and further loss of sight prevented.

For primary open angle glaucoma, the treatment options include:

• Medications to reduce pressure in the form of eye drops are the most common form of treatment and must be used regularly.
• Laser (laser trabeculoplasty) is performed when eye drops do not stop the deterioration of the field of vision.
• Surgery (trabeculectomy) is performed usually after eye drops and laser have failed to control the eye pressure and involves creating a new channel for the drainage of fluid.

Acute angle-closure glaucoma requires urgent treatment to prevent damage and worsening of vision. Treatment modalities include Eye drops, oral or intravenous medications, laser surgery and sometimes surgical treatment.

Patients should continue to have regular check-ups to detect any worsening of the glaucoma and prevent visual loss.