Raising awareness of the silent thief of sight

Posted on March 07, 2016

Glaucoma is one of the leading causes of irreversible blindness in the world. This condition often referred to as the silent thief of sight, indeed creeps in like a thief in the night and snatches sight away from its unsuspecting victims – silently and painlessly. This year we will be celebrating World Glaucoma Week from 6 to 11 March, and local and international eye healthcare professionals will commit their time and share their knowledge to raise awareness of and demystify this condition.

Glaucoma is a condition that causes progressive damage to a person’s vision, which only becomes apparent much later in the disease process. While treatment is effective in halting the disease, it cannot reverse damage already caused. This means that the sooner it is diagnosed, the less damage is done and the more vision there is to save. It is interesting to note that while anyone has a 2,3% lifetime risk of developing glaucoma, those with a first-degree relative affected by the condition are ten times more at risk. Globally, glaucoma affects up to 2% of individuals over the age of 40 and up to 10% of people over the age of 80. As many as 50% of sufferers may remain undiagnosed.

According to Dr Prisilla Makunyane from the Department of Ophthalmology in the Faculty of Health Sciences at the University of Pretoria, many glaucoma cases are only diagnosed incidentally when patients visit an ophthalmologist or optometrist for the treatment of other minor ailments like dry eyes. She says that a common scenario with which eye care professionals the world over are familiar, entails a puzzled and agitated adult walking into a consulting room, bumping into desks and objects that he/she should have been able to detect in his/her peripheral vision. She says that these patients often relate a history of a slowly progressing, painless visual deterioration which they largely ignored or casually managed by using reading glasses. Dr Makunyane explains that patients with glaucoma typically lose their peripheral vision first and then, usually only much later, their central vision. This means that they only notice that there is a problem with their vision at an advanced stage of the condition, normally when they realise that they are unable to see cars approaching from either side while driving, or when they undergo the mandatory eye test when they renew their drivers’ licences at the Traffic Department.  

Dr Makunyane says that another common scenario is that of a patient who, when covering one eye, notices that he can see markedly better with one eye than with the other. She explains that although there are cases where glaucoma affects only one eye while the other continues to function normally, it is far more common for these patients to suffer from a type of glaucoma known as open-angle glaucoma, where both eyes are affected but the speed of progression of the disease is not the same in both eyes. Primary open-angle glaucoma is common and aggressive in people of African descent and is also prevalent among diabetics, myopic (short-sighted) individuals and patients who suffer from diseases of the heart and blood vessels.

Glaucoma can be hereditary, or may arise as a complication of, or in association with many other conditions, such as blunt-instrument injuries to the eyes or various inflammations, infections and tumours. Generally, it results in damage to the optic nerve, which causes characteristic visual field defects due to high intra-ocular pressure. If discovered early enough, the condition can be treated and visual loss can be halted or at least significantly slowed down. Treatment can be either medical, with the use of eye drops and/or tablets, or surgical. Treatment options are usually determined by the treating ophthalmologist after careful assessment.

‘The socio-economic implications of irreversible blindness are enormous and negatively impact family units, standards of living and the economy as a whole,’ says Dr Makunyane. ‘I urge everyone to visit an ophthalmologists or optometrist to be screened for this condition and to ask relevant questions regarding glaucoma. The best thing you can do for yourself is to have your eyes checked annually by an eye care professional if you are at high risk of developing glaucoma, or otherwise every two years. Encourage your loved ones, friends and colleagues to have their eyes checked regularly too.’


- Author Ansa Heyl

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