Johannesburg - Mary Tlholoe was born blind. When she was six months old, she had her first eye operation and wore her first pair of spectacles. Her diagnosis – early childhood glaucoma.
Tlholoe, now 27, had her latest in a long line of operations last month, and while she can now see with the aid of her spectacles, her vision is still extremely poor.
“Sometimes I lock myself in a room and cry and ask myself: Why? Why me? Sometimes I worry I’ll wake up and can’t see anymore,” she said.
Glaucoma, a disease of the optic nerve, is the leading cause of irreversible blindness worldwide.
As part of Glaucoma Week, which runs until Saturday, Tlholoe, a Kagiso resident, spoke on Wednesday at St John’s Eye Hospital in Soweto of her daily struggle to see.
“In 2007, I had a tube touching my cornea when I walked in the sunlight, I could feel it. By the time it was repositioned, my vision had been damaged further, and it hasn’t been the same since then,” she added.
Dr Sue Williams, a consultant ophthalmologist at St John’s, said glaucoma caused progressive loss of the retinal nerve fibres, which led to cupping of the optic nerve. This caused visual-field changes.
Williams, who has extensively researched the genetics of glaucoma, said that in most cases, patients presented late because they did not perceive the “black hole” caused by the loss of the visual field, called scotoma.
“Patients develop tunnel vision with advanced glaucoma… and because vision is subjective, your patient with glaucoma isn’t aware they have the disease, and that’s what makes it a dangerous and blinding disease,” she added.
There are two types of glaucoma: primary, which is more prevalent, and secondary.
The two types do not have a defined cause and develop by themselves.
In secondary glaucomas, pressure damages the optic nerve. This can be caused by trauma or diabetes. “Because there’s still a lot we don’t know about glaucoma, genetics is one way of finding more details about it. It is quite important to predict the disease,” Williams added.
On Wednesday, there were queues at the dispensary, and the benches were full of patients waiting to be treated. Williams said that was the norm.
“We treat 1 200 a month – a third of them new patients.”
Because of the patient loads and cost constraints, staff could not go out into the community to screen for eye diseases, she said. - The Star