Diabetic Retinopathy

How can diabetes affect the eye?

Diabetes affects the very small blood vessels at the back of the eye (the retina). Diabetes causes these blood vessels to leak fluid, haemorrhage (bleed) and block. Eventually, small abnormal blood vessels can grow, resulting in severe haemorrhaging inside the eye, scarring and retinal detachments.
The symptoms of diabetic retinopathy are varied. These include blurred vision, floaters, patchy vision and sometimes there may be no symptoms at all. It is therefore very important to be regularly checked by either your optometrist or ophthalmologist.

Is diabetic retinopathy common?

In Australia, diabetic retinopathy is the most common cause of irreversible vision loss in people aged 25 - 70 years old.

Which tests do I need to detect macular degeneration?

Broadly speaking, there are 2 types of diabetic retinopathy:

diabetic maculopathy, which affects the central retina; and
diabetic (peripheral) retinopathy, which affects the peripheral retina.

Diabetic retinopathy is further divided into early, non-proliferative diabetic retinopathy (NPDR), or late, proliferative diabetic retinopathy (PDR). Mild forms of NPDR are very common and don't require treatment, however PDR is a severe disease and laser treatment is required to reduce the risk of blindness.

Here is a picture of a patient with diabetic maculopathy.

I am diabetic, how can I minimise my risk of vision loss?

You can reduce your risk of developing significant eye disease by:

optimising your long-term blood sugar control
reducing weight through regular exercise and healthy eating
not smoking
controlling your blood pressure and cholesterol
having regular eye check-ups to detect disease earlier rather than later.

What tests will I require?

Most of the time, no tests are required, just a simple examination of your eyes. However, in some cases an OCT scan to assess diabetic maculopathy may be required.

In severe cases, a fluorescein angiogram may also be required to fully assess the retinal blood flow.

What is the treatment of diabetic eye disease?

Firstly, you should ensure that your general health and diabetes is as well controlled as possible and try to cease smoking.

Treatment for your eyes depends on what type of diabetes your eye has.

Diabetic maculopathy

The gold standard for treating centre-involving maculopathy is intravitreal injections.

The most commonly used medications are 'anti-VEGF' agents such as Aflibercept (Eylea) and Ranibiumab (Lucentis). These usually need to be repeated every one to three months to maintain the best possible vision.

Intravitreal steroid injections are also commonly used. Recently a dexamethasone implant (Ozurdex) has been approved for diabetic patients, and has the potential for less frequent injections.

Retinal laser can also be useful in some types of maculopathy, however, as it does not significantly improve vision and can cause scarring of the macula, it is less commonly used now than what it was previously.

Here is an OCT scan of a patient before (top) and after (bottom) treatment with regular intravitreal injections:

Diabetic retinopathy

The main treatment for peripheral retinopathy is pan-retinal laser. This usually takes several thousand laser burns to the eye and will take several sessions for complete treatment.

For more information on intravitreal injections, please click here.

For more information on retinal laser, please click here.

Other resources

Diabetes Australia: www.diabetesaustralia.com.au

PDF files of articles Dr Johnson has written for the Medical Forum Magazine: