Diabetic eye disease — most commonly called diabetic retinopathy — is a complication of diabetes that affects the blood vessels in the retina, the light-sensitive tissue at the back of the eye. It is the leading cause of preventable blindness in working-age adults in Australia.
Like many diabetes complications, diabetic retinopathy develops silently. In its early stages it causes no pain and no change in vision — which is precisely why regular eye screening for anyone with diabetes is so important. By the time vision problems are noticed, the disease may already be advanced.
The good news is that when caught early, diabetic retinopathy is highly treatable, and much of its vision-threatening impact can be prevented.
How does diabetes affect the eyes?
The retina is one of the most blood vessel-dense tissues in the body, and those vessels are particularly vulnerable to the effects of chronically high blood glucose. Over time, high blood sugar weakens the walls of the retinal blood vessels, causing them to bulge, leak fluid or bleed. As the condition progresses, new abnormal blood vessels may grow across the retina — a process called proliferative retinopathy — which can cause more serious bleeding, scarring and, ultimately, retinal detachment.
A related condition, diabetic macular oedema (DMO), occurs when fluid leaks into the macula — the central part of the retina responsible for detailed, central vision — causing blurring and vision loss.
Who is at risk?
Anyone with diabetes — type 1 or type 2 — can develop diabetic retinopathy. Risk increases with the duration of diabetes and is strongly linked to how well blood glucose and blood pressure are managed over time. After 20 years of living with diabetes, the majority of people will have some degree of retinopathy, though not all will develop the vision-threatening forms.
Additional risk factors include high blood pressure, high cholesterol, pregnancy in women with diabetes and smoking.
What are the symptoms?
In the early and moderate stages, diabetic retinopathy typically has no symptoms. As it progresses, symptoms can include blurred or fluctuating vision, floaters or dark spots, difficulty seeing at night, colours appearing washed out and, in severe cases, sudden vision loss.
If you experience any sudden change in your vision, seek urgent medical attention.
How is it detected and treated?
Detection relies on regular dilated eye examinations — a straightforward procedure in which eye drops are used to widen the pupil, allowing the eye specialist to examine the retina thoroughly. Digital retinal photography is also widely used for screening.
People with diabetes should have a comprehensive eye examination every 1 to 2 years. More frequent review may be recommended depending on the level of disease found.
For early diabetic retinopathy, the most effective treatment is optimising blood glucose, blood pressure and cholesterol control. When the condition progresses, several treatment options are available including laser therapy, anti-VEGF injections (medications injected into the eye that target the abnormal blood vessel growth) and vitreoretinal surgery for advanced cases.