By Dr Shabbir Mohamed

Recently, in my practice, I saw a patient who has presented with significant irreversible visual loss from a condition called Glaucoma. I therefore wanted to use this opportunity to educate our community members on this condition and urge all members to regularly visit their optometrist (optician) to be screened for this disease and to have a general eye examination to look for other potentially treatable diseases.

What is Glaucoma?

Glaucoma was first described by a muslim physician (Al-Tabari) in the 10^th Century. He recognised that a group of patients became blind who also had a firm eye to the touch. He also noted that there were some groups in whom the blindness occurred suddenly whilst in others, it was a more gradual process. The understanding of the disease has improved considerably since then.

Today, we know that glaucoma is a disease of the optic nerve. The optic nerve can be thought of as the cable that links the eye to the brain and allows the images captured by the eye to be transmitted and therefore analysed by the brain which allows us to see. We know that there are many different types of glaucoma but for this article, I want to mainly concentrate on primary open angle glaucoma which affects 2% of people over 40 in this country.

In this condition, the nerve becomes damaged near where it exits the eyeball. There are several factors that are thought to cause this type of damage such as poor blood flow, lack of nutrition, genetic influences, previous head trauma and raised pressure within the eye.

When the nerve gets damaged, the patient starts to lose vision in the periphery - what we term the visual field. Initially, the visual field loss is slight and the brain is very good at filling in the blanks so the patient is completely unaware of the visual loss. As the disease becomes more advanced, the patient may knock into things or trip over obstacles which they are unable to see in their peripheral vision. Other symptoms include not being able to see well in dim light and at night. It can also have an affect on driving and the law states that patients with glaucoma must inform the DVLA who will then investigate whether they are legally eligible to continue to drive.

The visual loss is irreversible but if the disease is identified early, treatment to prevent visual loss is very effective. Therefore, it is very important to pick up the disease in the early stages. Treatment initially is in the form of drops applied to the eye. Further treatment can involve laser treatment, tablets or surgery. All these treatments are aimed at controlling the pressure to prevent further damage to the optic nerve and thereby preserve vision.

Summary

Glaucoma is a disease which can cause significant visual loss and blindness. If it is identified early, treatment is very effective and sight loss can be prevented. Regular eye tests by the optician can identify the early signs of this disease. If you have not been to see your optician recently, please make an appointment and during the sight test, ask to be checked for glaucoma if you are over 40.