Glaucoma care

Glaucoma is a disease of the optic nerve, which connects your eye to your brain. It is often associated with raised pressure inside the eye, but some patients with normal intraocular pressure can still develop glaucoma. The pressure on the optic nerve results in tunnel vision, and in severe cases, loss of central vision as well. The pace of vision loss depends on the type of glaucoma, but it often occurs slowly, over many years. The higher the intraocular pressure, the more likely the patient is to develop glaucoma, but other risk factors can also play a role, such as age, family history, blood pressure, or a previous injury to the eye.

Diagnostic investigations

Diagnosing glaucoma can be difficult and often requires several years of monitoring. Regular tests include intraocular pressure measurement, examination of the optic nerve and structures that drain fluid from the eye, visual field testing, structural scans of the optic nerve, and occasionally MRI or CT scan.

Types of glaucoma

1. Primary open angle glaucoma

   This is the most common form, causing over 90% of glaucoma in western countries. This causes slow, painless loss of peripheral vision. A family history of glaucoma can indicate increased risk or severity.

2. Acute angle closure glaucoma

   This form occurs more commonly in the Asian population, and is caused by a narrowing of structures that drain fluid from the eye. When angle closure occurs, the eye pressure rises rapidly, which is painful, and requires immediate intervention to prevent permanent vision loss.

3. Secondary glaucoma

   Glaucoma caused by another condition—such as diabetes, vascular disease, or an injury to the eye—can sometimes occur. Depending on the cause, it may be open angle or angle closure glaucoma.

4. Normal tension glaucoma

   This type of glaucoma causes gradual loss of vision, despite normal eye pressure.

Treatment

Treatment is best commenced early, when there is minimal damage. Early treatment can prevent worsening of the damage to the optic nerve and vision, but does not reverse any prior damage. Glaucoma is mainly treated by lowering intraocular pressure. For most patients, this involves pressure-lowering eye drops and laser procedures, but severe case may require surgery.

Glaucoma suspect

A “ glaucoma suspect” is someone who has features of glaucoma that are not sufficient to warrant treatment.

Glaucoma suspects include patients who have the following:

• Raised intraocular pressure (range 20-30), with otherwise normal testing.
• Abnormal optic nerve anatomy, but normal optic nerve function.
• Abnormal visual field testing that is inconsistent, or does not correlate with other findings.
• A positive family history, along with one of the features above.

Glaucoma suspects require regular checkups with visual field testing and optic nerve assessment, typically on an annual basis. Family members should also be assessed. This is to idenfity any signs of progression that would confirm the diagnosis of glaucoma.