With World Glaucoma Week marked from Tuesday March 8 to Monday March 14, the South African Glaucoma Society and the World Glaucoma Patient Organisation are hoping to spread awareness of glaucoma, the second most common cause of blindness worldwide.
Glaucoma is a group of eye diseases that cause progressive damage of the optic nerve at the point where it leaves the eye to carry visual information to the brain.
If left untreated, most types of glaucoma progress (without warning nor obvious symptoms to the patient) towards gradually worsening visual damage and may lead to blindness. Once incurred, visual damage is mostly irreversible, and this has led to glaucoma being described as the “blinding disease” or “the sneak thief of sight”.
It is estimated that 4.5 million people globally are blind due to glaucoma and that this number will rise to 11.2 million by 2020. Due to the silent progression of the disease – at least in its early stages – up to 50% of affected persons in developed countries are not even aware of having glaucoma. This number may rise to 90% in underdeveloped parts of the world.
There are several types of glaucoma. Some may occur as a complication of other visual disorders (the so-called “secondary “ glaucoma) but the vast majority is “primary”, meaning they occur without a known cause. It was once believed that the cause of most or all glaucomas was high pressure within the eye (known as intraocular pressure, sometimes abbreviated as IOP ). It is now established, however, that even people with abnormally high IOP may suffer from glaucoma. Intraocular pressure is considered therefore today as a “risk factor” for glaucoma, together with other factors such as racial ancestry, family history, high myopia and age.
Some form of glaucoma may occur at birth (congenital) or during infancy and childhood (juvenile ); in most cases, however, glaucoma appears after the fourth decade of life, and its frequency increases with age. There is no clearly established difference in glaucoma incidence between men and women.
The most common types of adult-onset glaucoma are primary open angle glaucoma ( POAG) – a form most frequently encountered in patients of Caucasian and African ancestry – while angle -closure glaucoma ( ACG), is the more common in patients of Asian ancestry. ACG is often chronic, like POAG, but can sometimes be acute, in which case it usually presents as a very painful ocular condition leading to rapid vision loss.
There is no cure for glaucoma as yet, and vision loss is irreversible. However, medication or surgery traditional or laser) can halt or slow down any further vision loss. Therefore, early detection is essential to limiting visual impairment and preventing the progression towards visual handicap or blindness. Your eye-care professional can detect glaucoma in its early stages and advise you on the best course of action.
There will be free glaucoma testing during World Glaucoma Week. For more information on participating eye-care professionals, call 021 426 2200.
For more information on glaucoma, log on to the South African Glaucoma Society’s website at www.sags.com