Glaucoma the 'thief of sight'

Glaucoma is a group of eye conditions that cause damage to optic nerve of the eye, which each year results in large numbers of people around the world going blind. After cataracts glaucoma is the second most common cause of blindness both in South Africa and globally. Glaucoma is often known as the ‘thief of sight' because it does not usually present any symptoms and people are therefore unaware they have it until their eyes have been seriously damaged by the disease and they are no longer able to see.

While most forms of this medical condition cannot be cured, treatment can minimise or prevent damage to the optic nerve thereby reducing vision loss. This is why it is so important for people to visit their optician or eye doctor regularly and have their eyes examined for glaucoma.

Taking control of your health with GEMS
At the Government Employees Medical Scheme (GEMS) we encourage our members to take control of their health and deal with any potential health problems such as glaucoma as early on as possible. World Glaucoma Week is held 10-16 March and this article forms part of the GEMS commitment to providing our members with information and support that will help them to live a healthy life.

What is it?
There are a number of different types of glaucoma but the most common form is known as open angle glaucoma. The eye contains a fluid called aqueous humor which is drained via tiny vessels. If this fluid is slowed or blocked it causes pressure to build in the eye. This is called intraocular pressure and if it is allowed to continue to build up unchecked it can cause damage to parts of the optic nerve and even cause a complete loss of vision within the space of just a few years. This is why it is so important for the condition to be identified and treated as soon as possible.

It is not known what causes open angle glaucoma although it does tend to run in families. There is also no known way to prevent it. As already noted, there are also generally no symptoms associated with open angle glaucoma although poor vision in dim light and blurred vision may be signs that one could be developing the condition. Some individuals are certainly more at risk of developing glaucoma than others and they should be extra vigilant.

Who is at greater risk of developing glaucoma?
The following may increase the risks of developing glaucoma:

• Elevated internal eye or intraocular pressure. If your intraocular pressure is higher than normal you have a greater risk of developing the condition. Intraocular pressure tends to increase with age;
• Age. Those over the age of 60 are at risk;
• Family history. Individuals who have had family members with glaucoma develop the condition more often than those who have not;
• Medical conditions. Those with conditions, such as diabetes, high blood pressure, heart disease and migraine are at greater risk;
• Ethnicity can play an important role with larger numbers of people of African descent developing open angle glaucoma;
• Other eye conditions may cause intraocular pressure including eye injuries and tumours. Being near- or far-sighted may also increase the risk.

How often should my eyes be tested?
Regular eye testing is the only real way to detect glaucoma. It is therefore advisable to have your eyes tested at an optometrist or eye doctor every five years or so. Make sure your eye care practitioner is able to undertake a glaucoma screening in addition to being able to perform the usual vision tests. It applies to:

• Those who are over the age of 40 should be tested once every two years while individuals who are over the age of 60 should be tested annually;
• Those with a family member who have had glaucoma should be tested regularly. This is especially important in a case where the family member was younger than 40 years of age when they developed the disease;
• Individuals of African descent who have had a family member with glaucoma should ask their eye-care practitioner how regularly they should be tested.

Individuals who suffer from diseases such as high blood pressure and diabetes must be sure to regularly visit their doctor who will assist them in controlling these conditions. If they remain uncontrolled these diseases can do a great deal of damage to the eye and contribute to the development of glaucoma.

Will I become blind?
A few years ago glaucoma was sure to result in the loss of eyesight. Today however there are a range of medications and procedures available and the symptoms of the condition can be effectively treated, preventing the loss of vision. The goal of treatment is to stop further damage to the optic nerve from occurring, which is usually achieved using eye drops or other medications. Surgery is also occasionally used in certain cases.

It is important to note that the treatments for open angled glaucoma are designed to stop pressure building up in the eye. If the glaucoma sufferer stops his or her medication the pressure will build up very quickly once more and could cause damage to the ocular nerve. For this reason it is critical that patients should never stop using their eye drops or taking their medication. Most people do not experience severe side effects from the treatment. However, if they do have any problems with their treatment they should discuss these with their doctor.

References
1. WebMD - http://www.webmd.com/eye-health/glaucoma-eyes
2. PubMedHealth - http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002587/
3. Mayo Clinic - http://www.mayoclinic.com/health/glaucoma/DS00283/DSECTION=risk-factors
4. South African Glaucoma Society - http://www.sags.co.za/faqs