Diabetes is an increasingly concerning health problem in New Zealand – with more than 250,000 Kiwis living with the condition and an expected increase by as much as 90 per cent over the next 20 years.
That alarming prediction comes from a 2021 Diabetes New Zealand report and one of the most common complications associated with diabetes is also the leading cause of preventable blindness in adults.
Diabetes can damage the tiny blood vessels in the retina at the back of the eye. As many as one in three Kiwis with diabetes has some sign of diabetic retinopathy with New Zealand's largest eye health provider, Specsavers, saying they treat more than 700 patients for the condition each week.
Some patients with diabetic retinopathy might not experience any symptoms or don't realise they have a problem with their eyes until it progresses to an advanced stage. Others might experience worsening vision, sudden vision loss, floaters, blurriness, dark areas of vision or difficulty recognising colours.
Early detection and treatment is vital as Specsavers say it can prevent up to 98 per cent of severe vision loss. If left untreated, diabetic retinopathy can lead to irreversible blindness.
Specsavers optometrist Celeste Raisbeck says: "For a person living with diabetes, the most important thing to look after your sight is to manage your diabetes and blood sugar levels, lead a healthy lifestyle, and get your eyes tested every two years.
"Diabetic retinopathy can progress without much fanfare which is why it's so critical we detect it as early as possible.
"As the disease progresses, some of the blood vessels that nourish the retina can become blocked, depriving the eye's blood supply. When this happens, the brain sends signals to grow new blood vessels; these can be fragile, leaking blood into the centre of the eye – causing blurred vision and blindness.
"Macular oedema can also occur," says Raisbeck. "That's when fluid leaks into the macula, the central part of the retina responsible for our central vision, causing swelling and blurred vision."
If diabetic retinopathy is picked up early enough it can normally be treated with careful diabetes management. Advanced cases may require laser treatment, eye injections or surgery by an ophthalmologist.
Diabetes can also affect the eye in other ways, leading to an increased chance of other sight-threatening conditions, including glaucoma and complications with cataracts.
People with diabetes are twice as likely to develop glaucoma, which causes damage to the optic nerve often resulting in the gradual loss of peripheral vision. If left untreated, glaucoma can also lead to irreversible vision loss.
Much like glaucoma, people with diabetes are also more likely to experience cataracts, which can be intensified because of their diabetes. Cataracts are caused by the lens of the eye becoming opaque due to a build-up of proteins which minimise the amount of light that passes through the lens, preventing clear images being sent to the retina. Symptoms include cloudy or blurry vision, spots, sensitivity to bright lights, seeing circles around light sources, and yellowing of vision.
Raisbeck understands the challenges faced by people living with diabetes: "Diabetes is a complex condition; people with diabetes need to have a range of regular health checks and tests to manage their condition. I understand it can be time-consuming and sometimes things get overlooked – and many people with diabetes don't even know they need to have their eyes checked.
"Even individuals with well-controlled diabetes can develop diabetic retinopathy, so regular eye tests are critically important. If we detect problems early then patients can get early treatment, damage can be prevented and they can keep their sight."
According to Diabetes NZ, an estimated one in four New Zealanders are living with undiagnosed pre-diabetic symptoms.
"Sometimes we even have patients unaware they have diabetes. It gets detected in their eye test, so this simple test can save a person's vision or even their life," says Raisbeck.
All Specsavers stores have hospital-grade technology to help their optometrists detect diabetic retinopathy, and other sight-threatening eye conditions, early through an advanced 3D scan of the back of the eye.
Raisbeck's top tips to manage diabetes and keep eyes healthy:
- Manage blood glucose, blood pressure, and cholesterol
- Eat healthy
- Maintain an active lifestyle
- Discuss quitting smoking with your GP
- Have eyes tested regularly