GLAUCOMA

Glaucoma

Glaucoma is a common group of eye conditions. It's particularly dangerous as often there are little or no symptoms until it's too late. Regular sight tests mean early detection and treatment as soon as possible. It affects peripheral vision, and as it's a very slow process, people don't notice that anything is wrong. Left untreated, it can result in severe tunnel vision.

Why are my intraocular pressures important?

The fluid at the front of the eye (between the coloured iris and the clear cornea) is called the aqueous humour, and it keeps the cornea nourished and healthy. Because it's inside your eye there needs to be balance between production of fresh aqueous and draining of old aqueous.

In glaucoma the aqueous can't flow away and so remains in the eye. This results in the pressure of the eye going up. The pressure presses on the eye and although you can't feel it, it begins to damage the soft and sensitive optic nerve at the back of the eye.

The optic nerve is made up of millions of tiny fibres which carry all the information from your eyes that make up your vision. If these become damaged, then vision will be affected. In Glaucoma the fibres relating to peripheral vision are damaged and this causes loss in peripheral vision.

So what are the treatment options?

There's no cure as such, but medications are prescribed to reduce pressure in the eye and prevent ongoing damage. These work in a variety of ways but all are designed to lower pressure. Sometimes a combination of drops may be used, or sometimes a minor laser procedure may be done by an eye consultant at the hospital which will also help lower the pressure.

Can I do anything to prevent it?

Regular sight tests! There's nothing you can do or take to prevent glaucoma from occurring, but regular sight tests allow us to detect the earliest possible changes and refer you to a specialist before it may even have started to cause you any noticeable problems.

What are the different types of glaucoma?

There are different causes for the pressure to rise in the eye and this affects which type of glaucoma you have. Sometimes the gap between the cornea and the coloured iris is very narrow. This means that the drains where the aqueous leaves the eye become blocked and this causes the pressure to rise dramatically. This is referred to as angle closure glaucoma.

If the angle between these two is wide open, the aqueous can reach the drainage structures but they may be blocked for some other reason. This is referred to as open angle glaucoma.

My pressures are high – do I have glaucoma?

Not necessarily. The pressure required to damage the optic nerve is individual. We have a range of “normal” pressures, but if your pressure is outside of this range you may not have glaucoma. Similarly if your pressures are within this “normal” range you can still develop glaucoma.

It depends on how sensitive your optic nerve is. If you have a very tough optic nerve, the pressure can still be very high and yet it does not get damaged by glaucoma. Also, you may have a very sensitive optic nerve, and although the pressure may be considered “normal” it may still be too high for your eye and so the pressure will need to be dropped before any damage occurs.

So what can Davis Optometrists do?

Firstly, a regular sight check will allow us to monitor your vision and ocular health, but specifically for glaucoma we can look closely at:

• Your intraocular pressure

• Your peripheral vision

• Your optic nerve health

By having regular checks we can see changes at the earliest opportunity. It's always recommended that you try to stay with the same Optometrist as they will have your records from before. It's often vital to look at your notes from previous visits to see any subtle changes.

Importantly, we have a 3D OCT machine. This works much like an ultrasound machine in that it allows us to look at the layers underneath the retina, but also look at the optic nerve. This machine is very advanced and only normally found in the hospitals so to be able to have it performed as part of your standard sight test is very useful when checking your eye health.

Because we can look at your optic nerve in 3D, we are able to inspect it closely and monitor it carefully, helping us to safeguard the health of your eyes.