By Jessie Taylor
Glaucoma is the second leading cause of blindness in South Africa and the world. However, this condition is often left undetected, leading to irreversible vision loss. Yet testing for this illness is quick and painless and can prevent permanent damage to the optic nerve.
This is the message that World Glaucoma Week aims to spread. The awareness week runs between Sunday the 6th and Saturday the 12th of March and is a clarion call to all South Africans to get tested for glaucoma and other eye diseases.
A gradual progression
Glaucoma is the second most common cause of blindness worldwide, with around 4.5 million people suffering from the disease globally. In South Africa, it is estimated that about 200 000 people are affected.
Glaucoma is a group of eye diseases that cause progressive damage to the optic nerve. The disorders affect the point of the optic nerve where it leaves the eye to carry visual information to the brain. The condition sees patients develop a specific pattern of progressive damage to the optic nerve. This usually begins with a slight loss of peripheral vision.
The eye has internal pressure, created by a clear fluid that flows through the eye which drains into the blood via an area called the anterior chamber angle. However, in glaucoma patients, this outflow is obstructed and this, in turn, causes increased eye pressure. This pressure can, over time, damage the optic nerve.
If left untreated, glaucoma can progress gradually towards blindness without giving any warnings or obvious symptoms to the patient.
Glaucoma is not preventable, and anyone can potentially develop it. The disease is common in South Africa and particularly affects those of African descent. This is why it’s essential to have regular eye tests.
Testing and treatment
Because of the silent progression of the disease, especially in the early stages, almost half of all people in the developed world don’t realise they have glaucoma. In developing nations, this is insignificantly higher – as much as 90% of those with the disease don’t are undiagnosed.
While there is no cure for the damage caused to the optic nerve by glaucoma, cases that are diagnosed in time can be managed and controlled.
The recommended treatment will depend on the type of glaucoma, but most treatment plans aim to reduce the pressure in the eye.
Some treatment plans may include eye drops and medication to reduce the pressure in the eye or reduce the rate at which fluid is produced. Laser treatment may also be used to open the drainage angle and to reduce intraocular pressure. As a last resort, surgery may be used to create a new passage for fluid drainage.
The vision loss caused by glaucoma is irreversible. This means that early detection is essential to limit the visual impairment caused by the disease and prevent its progression. Not only will this ensure your visual health, but it will also reduce the impact of this disease on society.
The complications caused by glaucoma can be considerable by limiting the individual’s economic activity and creating a demand on healthcare.
What causes glaucoma?
Glaucoma can be caused as a complication of another disease, but most cases do not have a cause.
The most common types of adult-onset glaucoma are Primary Open Angle Glaucoma, which is found most frequently in Caucasian and African patients, while Angle-Closure Glaucoma is often found in Asian patients. The third type of glaucoma is Angle-Closure Glaucoma – a chronic and sometimes acute condition that is often painful and leads to rapid vision loss.
A child may be born with glaucoma or develop it during childhood, but most cases develop later in life in adults who are over 40. Both men and women are affected equally.
One of the risk factors for glaucoma is high pressure within the eye (intraocular pressure), as well as advanced age, racial ancestry, family history and high myopia.
Those with a family history of the condition; who are nearsighted; or who have medical conditions such as diabetes, heart disease, high blood pressure and sickle cell anaemia should all undergo frequent testing as they get older.
How do I test for glaucoma?
A test for glaucoma can be done at any optometrist, using a machine to send a puff of air into the eye. This test determines the intraocular pressure of your eye. If your optometrist finds any irregularity, you will be referred to an ophthalmologist who specialises in eye and vision care. The ophthalmologist will run tests for optic nerve damage, cornea thickness and loss of peripheral vision, among others.
If you are younger than 40, you should have your eyes tested every two to four years. Between the age of 40 and 54, this should increase to every one to three years. Tests should take place annually from the age of 55.
South African Glaucoma Society
Glaucoma Research Foundation
National Eye Institute (NHI)