Glaucoma, “the silent thief of sight”
Glaucoma It can develop imperceptibly over the course of years, even leading to blindness if undetected. We look at the value of regular eye checks and who should be particularly aware.
Glaucoma is one of the most common chronic eye diseases in old age, affecting around some 2% of those over 40 and 10% of the over-85s, says Professor Stephen Vernon, a glaucoma specialist and Vice-President of The Royal College of Ophthalmologists. “The name covers various conditions relating to damage to the optic nerve. Glaucoma generally develops over the course of years, though some types develop in a matter of days or weeks, and it is even possible to be born with it.”
Because it usually takes the form of chronic or slow onset without symptoms, regular checks for early detection are essential, says Vernon. “It’s commonly understood to affect your peripheral vision, but in fact glaucoma initially affects bits of the sight relatively close to the central vision, causing blank patches which gradually spread outwards and inwards. It can eventually lead to total loss of vision, and still commonly does in places like Africa where detection levels are lower than in Europe.”
What should we look out for and who is most at risk?
“Everyone over 40 should have an eye check at least every two years,” stresses Vernon. “Glaucoma’s called the silent thief of sight because it has no symptoms until it’s very severe. Those who have a sibling with diagnosed glaucoma, and those of Afro-Caribbean extraction should be particularly careful because they are more prone.”
And he’d add a surprise third group – drivers.
“I’ve had a number of patients, typically males who’ve always bought reading glasses off the shelf and turn up for their first eye check at 65 or 70 with visual symptoms; they can read the eye-test board perfectly well but they’ve actually lost a lot of side vision and have advanced glaucoma. At their first consultation I have to advise them that they have to stop driving immediately and inform the DVLA .”
Current and future treatments
Most cases of chronic glaucoma can be treated with eye drops, which usually cause no, or very minor side effects but have to be used for life. Next lines of treatment are laser treatment and surgery, which are both increasingly successful and safe. Vernon says procedures called MIGS – minimally invasive glaucoma surgery – are also becoming more popular for early-stage glaucoma.
In the coming decades, he sees exciting developments in gene therapy: “Glaucoma is related to many genes; it would be a lot easier to identify and treat if it were a one-gene disease. If we can find out which affected gene a patient has and replace local cells to keep the eye pressure down, that could solve the problem.”
One of the main issues with glaucoma is detection and monitoring. “The number of patients will increase by 44% over the next 20 years in our ageing population – a huge increase that will be quite a drain on the health services,” explains Vernon. “You can’t just diagnose, give out some eye drops and forget about it: treatment needs to be monitored and adjusted as necessary.
“It can be very hard to prevent loss of sight when a patient has been detected late. It’s better to have glaucoma diagnosed than not. Everyone, get regular checks.”