An eye test can help detect if you have glaucoma

Daniel Hardiman-McCartney FCOPTOM

Clinical Adviser, The College of Optometrists

Sight loss from glaucoma is irreversible, but treatments will slow it down or stabilise it. This makes detecting the condition in the early stages essential.

Glaucoma is one of the leading causes of sight loss worldwide and in the UK. It is the name for a group of conditions where the optic nerve in the back of the eye becomes damaged. This is commonly caused by raised pressure in the eye, but there are also types of glaucoma that are not pressure related.

Remember – although glaucoma may be invisible to you, it is not invisible to your optometrist.

Symptoms can be subtle in early stages

The problem with glaucoma is that symptoms are not always noticeable in the condition’s early stages. Sight loss for those with glaucoma usually first occurs in the peripheral vision. It can be difficult to notice this type of sight loss because it is subtle and the brain compensates for it by filling in the missing images.

Thankfully, an optometrist can detect glaucoma during an eye examination, often before a person has any symptoms. There are several tests that all optometrists can do to pick up glaucoma, which may be performed during a routine eye examination:

• An eye pressure test (tonometry): During the sight test the optometrist will use an instrument to check the pressure inside your eye, when required.
• An optic nerve assessment: For this, your optometrist will look at the nerve at the back of the eye under high magnification to check for signs of damage; they usually use a special eye microscope called a slit lamp.
• A visual fields test: This test checks how well the optic nerve is working and can help detect small amounts of loss in the periphery of your vision. During the test you will be shown a number of light spots and asked to indicate which ones you can see.

Treatment options available

If glaucoma is picked up during an eye examination, your optometrist may perform additional tests or make a referral to a specialist glaucoma clinic for further investigation. If glaucoma is confirmed, treatments usually start with drops or special laser therapy to help reduce the pressure inside the eye.

Unfortunately, sight loss caused by glaucoma cannot be reversed, but treatments can help slow it down or stabilise it. Early detection is therefore crucial.

The College of Optometrists recommends regular sight tests, even if you don’t wear glasses or have any symptoms. Remember – although glaucoma may be invisible to you, it is not invisible to your optometrist.