What is glaucoma?

   by Eleanor Swystun, optometrist at Valli Opticians Almondbury and Valli Opticians Lockwood

Glaucoma is a disease of the optic nerve which usually occurs in people over the age of 40.

It is most commonly a gradual, slowly progressing disease. When the optic nerve is irreversibly damaged it causes it to thin, characteristically causing peripheral vision loss.

Glaucoma may or may not be associated with high pressure inside the eye. Pressure can increase if there is too much aqueous humor (the clear fluid filling the space in the front of the eyeball between the lens and the cornea) being produced, or if there is not enough drainage of the aqueous.

What causes glaucoma?

There are primary and secondary causes of glaucoma.

Primary causes:

•        High pressure inside the eye
•        Your age
•        Your family history
•        Whether you are short sighted or long sighted

Secondary causes:

•        Diabetes
•        Trauma/injury to the eye
•        Surgery
•        Inflammation within the eye

Who is at risk of developing glaucoma?

You are at higher risk of developing glaucoma if:

•        You have a parent, child or sibling with glaucoma
•        You are from African, Asian or Caribbean origin
•        You are diabetic

What are the early symptoms of glaucoma?

There are different types of the disease but the most common is chronic glaucoma. This type is often referred to as a silent disease as there are usually no symptoms.  Loss of peripheral vision is only noticed by a sufferer when the damage done to the optic nerve is at an advanced stage.

The other type is acute glaucoma, where the pressure inside the eye increases suddenly. There are clear symptoms with acute glaucoma which can include a very red painful eye, seeing halos around lights, blurring of vision, sickness and nausea.

During an eye examination we check for glaucoma on all our patients. It is therefore important to have your eyes tested regularly so that any changes can be picked up and referred to an ophthalmologist if necessary.

What is dangerously high eye pressure?

If the pressure inside your eye increases suddenly and is very high then it can cause damage to the optic nerve more quickly and can cause visual field loss to occur faster.

Extremely high pressure doesn’t just damage the nerve but can cause damage to other structures in the eye such as the cornea.

When the pressure increases dramatically in your eye you will experience symptoms including:

•        a very red eye
•        a very painful eye
•        seeing halos around lights
•        blurring of vision
•        sickness and nausea

If you experience any of these symptoms it is important you seek help immediately.

How is glaucoma diagnosed?

Glaucoma is usually picked up during a routine eye examination. During the examination your optometrist will perform these tests to check for glaucoma:

1. Pressure test: the optometrist will check the pressure inside your eyes to make sure they are within normal limits and both eyes are equal. (This is known by most patients as the “puff of air test”).

2. Checking the optic nerve: the optometrist will use their slit lamp to assess the optic nerve. Glaucoma causes characteristic changes to the nerve so the optometrist will look out for these.

3. OCT scan: This is a 3D scan of the optic nerve which helps determine whether the nerve is healthy. It scans beneath the surface allowing us to pick up changes to the nerve a lot sooner. Not every optician has an OCT but here at Valli Opticians a number of our practices have an OCT and we recommend a scan for all our patients.

4. Visual fields test: This checks your peripheral vision. Remember, glaucoma causes loss of peripheral vision so if your visual fields test shows abnormal results, it could be a sign you have glaucoma. The test is done routinely and especially if the optometrist suspects you may have glaucoma and some of the readings from the other eye tests have come back unusual.

What is the treatment for glaucoma?

There are different types of treatments for glaucoma.

The first would be eye drops to help reduce the pressure inside the eye (mainly by slowing down the production of the aqueous humor). Drops would need to be used daily and on an ongoing basis.

The second type of treatment is surgery or laser which helps to increase the drainage of the aqueous humor therefore reducing the pressure in the eye. Usually after this type of treatment you don’t need any more surgery, however you might still need to use eye drops.

Unfortunately, the damage already caused by glaucoma is irreversible. The treatment is to prevent any further harm.

Is glaucoma curable?

Glaucoma cannot be cured but it can be controlled by the treatments described.

Can glaucoma cause blindness?

If left untreated glaucoma can cause blindness. As said above the damage is irreversible so treatment cannot help recover the peripheral vision that has already been lost.

What foods should you avoid if you have glaucoma?

Research around glaucoma is constantly evolving. There are no definite set foods to avoid if you have the condition. Some ophthalmologists suggest avoiding high amounts of caffeine as it can raise the pressure in your eye. Others suggest low amounts of saturated fats and fatty acids.

Overall, it is best to reduce the amount of saturated fat you intake and eat a well-balanced diet.

The eye is a very active organ. Due to all the reactions and processes taking place the eye has very high metabolic activity. This allows oxidative stress to cause damage to the cells. To reduce oxidative stress, we need antioxidants in our diet. These include; dark green leafy vegetables, pomegranate, cranberries, green tea and flax seeds.

Before you change your diet, speak to your doctor if you are on any medications as some foods can interact with them.

Is glaucoma hereditary?

If your parent, child or sibling has glaucoma then you are 4 to 9 times more at risk of developing the disease. People over the age of 40 who have a family history of glaucoma get their basic sight test fee covered by the NHS. It is recommended they have a test every 12 months.

Can glaucoma be prevented?

Research is constantly evolving and although there is no real way of preventing glaucoma it is important to lead a healthy lifestyle with a well-balanced diet. Regular eye examinations are essential in picking up glaucoma.