For over 40 years we (Simpson Optometrist) have implemented several tests to detect Glaucoma, as early as possible. Breaking it down so that we can help our patients understand it better, I have often explained Glaucoma as a type of ‘plumbing problem’ inside the eye. Much more critical than your average pipe-burst situation; Glaucoma, if left undetected, can have a severe affect on your eyesight.

So what is Glaucoma? 

In a nutshell it it a build-up of pressure inside the eye. It is caused by an amount of fluid that feeds the structures inside the eye. There is either too much fluid or in fact the fluid is not draining away properly. These two factors can then result in increased pressure (known as IOP, intra ocular pressure) which is then determined as Glaucoma.

Am I at risk?

Glaucoma is not particularly common and affects approximately 2-3% of the population in Scotland. Diagnosis in children and those under the age of 40 is uncommon. Risk factors include age, family history of the condition, diabetes and high blood pressure.

Simpson’s Symptom-Detectors:

With advancing technology and a superb amount of high-quality kit available to us, we are fortunate that we have a number of different methods at our disposal, all of which we currently use in our own practice, in order to help pinpoint early detection. These include…

  1. Tonometry

This involves applying a small amount of pressure to the eye to test its resistance. Tonometry gives a measure of your current (intra ocular) pressure. Pressure measurements can vary throughout the day, so time of day is always noted. A normal pressure range is considered between 12 to 22 mm Hg. The measurement “mmHg” means “millimetres of mercury,” which are the units used to record eye pressure. If your test shows a pressure reading exceeding 20 mm Hg, you may have glaucoma or pre-glaucoma.

  1. Scans

There are certain scans that we use to look at the layers underneath the retina and optic nerve, in order to detect small changes which can indicate early Glaucoma. They can also be used to look directly at the drainage mechanism inside the eye to see how well it is working. These scans are known as OCT (Optical Coherence Tomography). 

  1. Visual Fields

Visual Fields denote how well you see the things around you that are not necessarily in front of you, but show from your side or peripheral vision. Small dots of light are shown in your field vision, whilst you are looking straight ahead. Difficulty in detecting these small changes can be related to Glaucoma. Not such an easy test for patients, however the information is still valuable.


In most cases with early detection Glaucoma is very treatable, either through drops or by using laser to improve the drainage mechanism. It is important to have regular check-ups to stay on top of this.

Do I need a check up?

If you are over 40 with none of the risk factors previously mentioned, two year check-ups are normal. Those at risk should be examined every year or even six monthly.

Worth noting…

There is also an acute form of Glaucoma. This is where the drainage mechanism blocks and pressure rises very quickly. Unlike the Glaucoma talked about earlier, which has no symptoms, the acute form is very painful and causes nausea and blurred vision. The patient would feel very ill and is immediately referred to ophthalmology for treatment. Usually this requires laser treatment and steroids to allow the fluid inside the eye to start draining properly. Raised pressure inside the eye leads to loss of nerve fibres, which means you start to lose areas of your visual field. This affects you in all kinds of ways in everyday life including sports, driving and even just getting around. With early detection and treatment your life can be relatively unaffected.

Questions or concerns?

We cannot stress enough the importance of your eye-health and are more than happy to book your free eyesight-MOT. Or for just £30 you will receive OCT for complete peace of mind and will be looked after by Sandie, Kim or Ross; who between them have over 30 years’ of experience with this and all other eye-health issues.

This week is National Glaucoma Awareness Week. If you feel changes in your vision and would like a 2nd (or 3rd or 4th opinion) then please just give us a call and we can arrange an appointment for you, no bother!

Cheers now,


Colin Simpson  B.Sc FBCO

Father of 3, Retired Optometrist, Grandpa, Blogger.