Denial is a blinding thing. Especially when you are a diabetic.

I was diagnosed with diabetes - defined as a chronic, complex and destructive disease in which my body is unable to use the glucose from the food I eat - when I was four.

Now, after 25 years of erratically attempting to manage my Type 1 diabetes on my own, I have been forced to confront the potential cost of my insistence on doing so: my sight.

I have fallen prey to diabetic retinopathy, the most common eye disease to affect diabetics and a leading cause of blindness in adults between the ages of 20 and 60.

I was shocked to learn that because of changes in the blood vessels of my retinas - the light-sensitive nerve layers inside my eyes that process light signals into nerve signals that are delivered to the visual brain centre - I had put myself at risk of being completely blind within six months.

While my failure to properly monitor and control my blood sugar has played a large part in the development of my retinopathy, the condition is also an almost inevitable consequence of having diabetes for a long time.

I am not a wildly out-of-control diabetic. I don't drink, smoke or take drugs. I have never not injected myself with the insulin I need to process my food and I eat healthily, avoid sugar and exercise regularly. But that was not enough.

Only regular monitoring and good control of my blood sugar and regular check-ups with an ophthalmologist could have helped me to avoid the severe diabetic retinopathy that I am now trying to improve with painful laser treatment.

This, according to ophthalmologist Dr Peter Ambrose, is because the longer a person has diabetes, the greater the chance that they will develop retinopathy.

Diabetics are also 25 times more likely to go blind, usually because of retinopathy, than non-diabetics.

"One study concluded that virtually everyone who was diagnosed with diabetes before age 30 has diabetic retinopathy within 15 years of their diagnosis," said Ambrose.

"About three-quarters of those who are diagnosed after age 30 have diabetic retinopathy within 15 years of diagnosis.

"Another study proved that after 20 years of diabetes, nearly all patients with Type 1 diabetes and more than 60 percent of patients with Type 2 diabetes have some degree of retinopathy," he said.

When Ambrose examined my eyes he told me that I had developed the most severe stage of the disease, proliferative diabetic retinopathy.

He explained the condition: "The lack of oxygen in the retina due to microvascular damage causes new fragile blood vessels to grow along the retina and in the gel-like fluid that fills the inside of the eye.

"These unhealthy blood vessels are not able to feed the retina. Without treatment, these blood vessels will bleed and cause floaters (spots in the eyes) and cloudy vision, and eventually destroy the retina."

According to Ambrose, I have also developed macular edema in my right eye.

"Macular edema occurs when the damaged blood vessels leak fluid and lipids onto the macula, the part of the retina that gives us central vision.

"The leakage makes the macula swell, which blurs vision and can occur at any stage of diabetic retinopathy," he said.

While there is nothing I can do to immediately improve the poor vision in my left eye, which can take up to three months to clear, I am undergoing laser treatment in both my eyes to prevent the retinopathy from progressing.

During this treatment, the pupils of my eyes are dilated and numbed with eye drops that contain local anaesthetic.

As I sit in front of the laser machine, a contact lens is placed on whatever eye is being treated first. The laser light passes through the contact lens and the pupil and is accurately directed at the many small vessels that have created the problem.

The laser works by clearing the vessels that have a tendency to bleed, and so prevents any further bleeding. It also destroys substances in the retina that support the unhealthy creation of small vessels in the surface of the retina.

Experts estimate that 2500 to 3000 tiny burns are needed to treat my severe retinopathy. The treatment is painful, but 95 percent successful in preventing blindness.

My brush with sightlessness has been difficult, forcing me to stop driving because of the poor vision in my left eye and making me dependent on others for help.

But it has also forced me to take real responsibility for the proper management of my diabetes.

The blood that now obscures my vision has made me see clearly that which I did everything to avoid acknowledging: I can no longer pretend that I am in control.

I only need to close my right eye, and try to see through my left, to see just how much I need help.

How is diabetic retinopathy diagnosed?

There are often no symptoms in the early stages of diabetic retinopathy, nor is there any pain. It is wise not to wait for symptoms before seeing an ophthalmologist, as your vision may seem unchanged until the disease becomes advanced.

Diabetic retinopathy can be detected with the following tests:

  • Visual acuity test: This test uses an eye chart to measure how well a person sees at various distances.

  • Pupil dilation: The eye-care professional puts drops into the eye to widen the pupil, allowing him or her to see more of the retina and look for signs of diabetic retinopathy.

  • Optical coherence tomography: Specialised imaging equipment is used to produce cross-sectional images of the retina, which can be used to measure the thickness of the retina and resolve its major layers. This allows for the observation of swelling and or leakage.

  • Fluorescein angiography: In this test, a special dye is injected into the arm. Pictures are then taken as the dye passes through the blood vessels in the retina. This test allows the ophthalmologist to locate leaking, blocked or neovascular blood vessels that is important in diagnosis and to plan treatment strategies.