What is diabetic retinopathy?

If you have diabetes, you’re at risk of developing diabetic retinopathy, a complication of diabetes that damages the light-sensitive layer at the back of the eye called the retina. This occurs because the retina at the back of the eye is supplied with blood by a delicate network of blood vessels.

Diabetes can cause the blood vessels to become blocked or leak, meaning the retina can’t work properly because it is not receiving a good blood supply. Left undiagnosed and untreated, diabetic retinopathy can lead to complications resulting in sight loss. Thankfully, with ongoing diabetes management and regular screening, you can protect your vision and reduce the likelihood of these visual complications.

Types of diabetic retinopathy

The stages of diabetic retinopathy are explained in various ways depending on who you speak to. At Specsavers we would break them down into the following four stages which covers damage to the retina’s blood vessels, this is known as retinopathy:

  • No retinopathy — there is no diabetic retinopathy visible, but we’ll continue to monitor this at each visit.
  • Background retinopathy — (also known as mild non-proliferative diabetic retinopathy - NPDR) — we can detect small changes to your blood vessels, usually seen as tiny bulges in the walls of the blood vessels supplying the back of your eyes. These can also bleed easily due to the weakening of the blood vessel walls, so some small haemorrhages may be detected. Your eyesight isn’t usually affected at this stage. Your optometrist will advise on the next examination interval.
  • Pre-proliferative diabetic retinopathy (also known as referable retinopathy) — we can see more severe and more widespread damage to the blood supply of the retina and there is a higher risk that your eyesight could be affected. You may at this stage be referred to a diabetic eye clinic to decide on how to reduce any further deterioration to the blood supply.
  • Proliferative diabetic retinopathy (PDR) – This is where, as a result of the poor blood supply at the back of the eyes, new vessels have formed to try and compensate for the reduced blood flow in the usual retinal blood vessel network. These new vessels are fragile and can bleed significantly and there may also be scar tissue formed on the retina which can lead to more serious sight-threatening problems such as retinal detachments. At this point there is a very high risk you could lose your eyesight and referral for potential treatment would be offered in order to try and stabilise your vision, however at this stage any vision which is already lost is unlikely to be restored.
  • Diabetic maculopathy — This is a form of diabetic retinopathy that occurs when the vessels supplying the central part of the retina, which is responsible for our central vision and seeing fine detail, become blocked or leak fluids, fats and proteins. At this point there is a significant chance that your eyesight will be affected, and it can impact your ability to read or see fine detail. Referral to a diabetic eye specialist would be necessary to determine if any treatment is indicated or for further monitoring.

Diabetic retinopathy causes

The retina is the light-sensitive layer that covers the back of our eyes and needs a constant supply of blood to keep it healthy. 

Diabetic retinopathy occurs when high blood sugar levels start to damage these blood vessels. The damage happens in three main stages (background, pre-proliferative and proliferative) all of which can be accompanied by diabetic maculopathy. It’s in the advanced stages that the vessels become weaker and blood can leak out and cause complications which may lead to vision loss.

How is diabetic retinopathy diagnosed?

As some of the features of diabetic retinopathy cannot always be detected through normal eye tests, a common method of detection and diagnosis is through diabetic eye screenings. These appointments are specifically designed to diagnose the condition, using dilating eye drops to get a wider view of the retina and taking photographs of the back of the eye.

Diabetic eye screening

Everyone with type 1 and type 2 diabetes will be invited to a diabetic eye screening programme from the age of 12, your GP can arrange this for you. This can be an annual or biennial check to assess the health of the retina and keep an eye out for any signs of diabetic retinopathy. In certain parts of the country, we provide this regular screening service on behalf of the NHS.

You should receive a letter from your local Diabetic Eye Screening Service inviting you to attend a screening appointment. The letter will include a leaflet about diabetic eye screening.

Diabetic eye screening is separate to your normal eye test, so you’ll still need to see an optometrist regularly. Along with testing your vision, your optometrist will also be able to check for any signs of diabetic retinopathy during your eye test. One way of doing this is with an OCT scan, that allows us to see all the layers within the eye and helps our optometrists to see any slight change in the retina that could signal diabetic retinopathy. 

Following a diabetic eye screening appointment, the photos from your screening will be assessed by a number of specialists, including someone who is trained in identifying and grading retinopathy. Within six weeks, both you and your GP should receive a letter with your results.

You may need to have a further assessment if:

  • The photographs are not clear enough to give an accurate result
  • You have retinopathy that could affect your sight and follow-up treatment or further assessment is needed
  • You have retinopathy that needs to be monitored more closely and checked more than once a year
  • Other eye conditions are detected, such as glaucoma or cataracts

If your results show no retinopathy or background retinopathy, you will be invited back for another screening appointment at the recommended screening interval. 

There’s a lot involved in the detection and diagnosis of diabetic retinopathy, so together with our in-house clinicians, we’ve put together everything you need to know about the tests and technologies used to do this effectively. You can read more here: What happens at a diabetic retinopathy screening?

Treatment and management of diabetic retinopathy

Treatment for diabetic retinopathy will depend on which stage of diabetic retinopathy is present and will only be necessary if your screening identifies that your vision is at risk.

Management in the meantime will usually involve maintaining a healthy lifestyle and keeping a close eye on your blood sugar levels.

For advanced stages of diabetic retinopathy, there are three main treatment options:

  • Laser treatment
  • Anti-VEGF injections into the eye
  • Surgery

Read more about how diabetic retinopathy is treated in the UK in our in-depth article.

Sir Steve Redgrave on diabetes

Sir Steve Redgrave CBE already won four Olympic gold medals in four consecutive games when he was diagnosed with type 2 diabetes in 1997.