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Your eyes continuously make a fluid inside your eyes so they have the nutrients they need to work normally. This fluid drains away naturally through tiny drainage channels (called the trabecular meshwork in an area described as the anterior chamber angle) in the front of your eyes. You can see where the angle is in the diagram below.

Your optometrist has found that your drainage channel is narrower than usual. This does not normally need any treatment. Many people have narrow drainage channels, and for most it never causes any problems. But, you may be at a greater risk of developing an eye condition called glaucoma.

anterior eye diagram

How are narrow drainage channels related to glaucoma?

Glaucoma is where the optic nerve, which connects the eye to the brain, becomes damaged. It’s usually caused by fluid building up and increasing the pressure inside the eye. Glaucoma can lead to loss of vision if it’s not diagnosed and treated early. There are two main types of glaucoma, chronic and angle closure.

Chronic glaucoma develops slowly and does not usually cause any symptoms. It affects the edges of your vision (peripheral vision) first. For these reasons, many people do not realise they have glaucoma, and it’s often only picked up during an eye examination. Most people with chronic glaucoma have normal drainage channels.

Angle closure glaucoma (ACG) is where the pressure inside your eye increases due to blockage or damage to the drainage channels. The increased pressure can come and go, and some people get short bursts of pain and blurred vision, particularly in low light. Sometimes the pressure increases, remains high and these symptoms do not go away – this is known as acute angle closure (AAC). Some people may also experience nausea and vomiting if these symptoms persist. Both ACG and AAC is more common in people with narrow drainage channels.

What symptoms of narrow drainage channels should I look out for?

If you notice the following symptoms that do not go away:

  • eye pain
  • blurry, hazy or misty vision
  • eye redness
  • halos around bright lights

You should go to the Accident and Emergency department immediately. These symptoms may be related to the narrow drainage channels, so refer to this page. The eye specialist can reduce the pressure and get rid of the pain.

If you have these symptoms and they appear to go away, your vision may still be damaged each time you notice them. This means you should see your optometrist as soon as possible and tell them you have had these symptoms.