Don't become another blinding statistic, James Muecke warns

Our sight is our most precious sense. It's why I wanted to become an eye surgeon: to protect sight, to restore sight, to give the gift of sight - not to take it away. And especially, not to take it away from somebody who has been needlessly blinded by an avoidable man-made disease such as type 2 diabetes.

These words opened my National Press Club address in December, the climax of my year as 2020 Australian of the Year. Fortunately, the need to remove an eye that's been destroyed by type 2 diabetes is relatively rare. What's not rare is the blinding threat posed by diabetes.

I received the national award for my work with Sight For All, a not-for-profit organisation dedicated to fighting blindness in some of the poorest communities of the world. Sight For All has been training and equipping eye surgeons throughout Asia and Africa so they can comprehensively and sustainably fight all blinding diseases they encounter, including diabetes. Diabetes is also a blinding threat right here in Australia; in fact, it's now the leading cause of blindness among working-age adults.

There are two reasons diabetes has become such concern. Firstly, the majority of cases of diabetes-related eye disease, or diabetic retinopathy, are due to type 2 diabetes, a largely avoidable dietary disease that globally has risen four-fold over the past four decades. Secondly, well over half of the 1.7 million Aussies with diabetes are not having their regular, all-important, sight-saving eye checks. When the eyesight suddenly drops, it may be too late to recover what's been lost. Take Neil Hansell for example.

Neil is an everyday Aussie bloke with a wife and four kids. He constructs light machinery for a living. He also has type 2 diabetes. A few years ago, at the age of 50, diabetes changed Neil's world forever. Unfortunately, he'd neglected his disease, and he paid the price. He went to bed one evening with normal sight and woke up the next morning blind, in both eyes. One of my colleagues worked hard to try to retrieve his sight. Unfortunately, it was too late. Neil was to spend the rest of his life in darkness. The thing that upsets Neil more than anything is that he can no longer see the wife and grandkids smile.

Sadly, Neil is not alone. He is just one of perhaps 150,000 Aussies with sight-threatening eye disease due to diabetes. How does diabetes threaten the sight? There are two main mechanisms. Firstly, the persistent high blood sugar levels in patients with diabetes damages the fine blood vessels of the retina, the light sensitive layer of tissue that lines the inside of the backs of our eyes. Blockage of these blood vessels can lead to a lack of oxygen flow in the delicate retinal tissue, ischemia, and this in turn can trigger the ingrowth of fragile new blood vessels, neovascularisation, a condition known as proliferative diabetic retinopathy. These abnormal blood vessels can, in turn, lead to bleeding inside the eye (or eyes), that can take away the eyesight in an instant, and sometimes permanently. More commonly, they give rise to the sudden appearance of floaters or shadows.

Fortunately, the blood can often be cleared from the jelly (vitreous) through a surgical procedure known as a vitrectomy. Occasionally, the blood triggers a scarring reaction on the surface of the retina that can detach the retina and threaten the sight a second time (tractional retinal detachment), a complication which demands sophisticated and highly exacting microsurgery by a trained retinal specialist. Fortunately, the success rate for re-attaching the retina in these cases is more than 75 per cent.

The other mechanism of sight loss is caused by damage to the inner lining of the blood vessels of the retina that can lead to leakage of fluid into the tissue of the central vision area, the macula, a condition known as diabetic macular oedema (DMO). This presents as blurring or distortion of the sight in one or both eyes. The commonest treatment for DMO involves the injection of an antibody (anti-VEGF) into the vitreous cavity. The anti-VEGF (Lucentis, Eylea, or Avastin) 'seals' up the leaky vessels, allowing the fluid to reabsorb and the eyesight to recover, or at least stabilise.

There are over 100,000 of these intra-vitreal injections performed every year in Australia for patients with sight-threatening eye disease due to their diabetes. This is a huge burden on our health system but, more importantly, on the lives of patients with this devastating complication, the most feared of the myriad of diabetes complications.

When 98 per cent of the blindness due to diabetes is preventable or treatable, this is one complication we should not be seeing here in Australia. Blindness has a far-reaching impact on both the patient and their family. If you have diabetes, remember to have regular eye checks. Better still, if you have type 2 diabetes, please speak to your GP or endocrinologist about potentially putting your condition into remission. I'm now advising all my patients with sight-threatening diabetic retinopathy that there is a sustainable dietary approach achieving remission success rates of more than 50 per cent. I'm beginning to see promising visual and health outcomes in these patients. It does require a little extra effort, but a lot less effort than for a life spent in darkness.