What is Diabetic Retinopathy? Symptoms & Screening

What is diabetic retinopathy?

Diabetic retinopathy is an eye condition that can happen if you have diabetes. Over time, high blood sugar can harm the small blood vessels at the back of the eye, called the retina. This can affect vision.

Early on, you might not notice changes, but without treatment, it can get worse and may cause permanent sight loss. Your optometrist (sometimes called an optician) will be able to spot signs of diabetic retinopathy during an eye test – and treatment is available if needed.

Whether you’re newly diagnosed or have lived with diabetes for years, eye tests help protect your sight.

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Retina
The light‑sensitive layer at the back of your eye where images are focused. High blood sugar harms small vessels in the retina.
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Damaged blood vessels
These can swell, leak or become blocked. This reduces oxygen and may blur or darken vision.
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Macular oedema
Swelling in the macula, which you use to see fine details. It’s a common cause of vision trouble with diabetic retinopathy.
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Vitreous haemorrhage
Fragile new vessels can bleed into the vitreous, the clear gel in the eye. This may cause sudden floaters or even vision loss.

What are the symptoms of diabetic retinopathy?

In the early stages, diabetic retinopathy might not affect your sight at all. That’s why many people don’t realise there’s a problem until the condition has progressed.

What does diabetic retinopathy look like? When symptoms do appear, they can vary depending on which part of the eye is affected. You might notice:

Blurred Vision
Floaters and flashes
Patchy or missing areas in your vision
Cloudy vision
Tunnel vision, where your side vision starts to narrow
Difficulty seeing at night
Halos around lights
Faded colours symptoms may come and go or get worse over time.

In severe cases, sudden vision loss can happen, often from bleeding or retinal detachment. This is rare but serious.
If you notice these changes, book a diabetes eye check as soon as you can. Early treatment can help.

Types of diabetic retinopathy

Diabetic retinopathy is often divided into two main types, based on how advanced it is and the changes in the eye.

Non‑proliferative diabetic retinopathy (NPDR)

The early stage. Tiny blood vessels in the retina are damaged and leak fluid or blood. Mild cases affect a few vessels. Moderate to severe cases cause more swelling and damage.

NPDR may have no symptoms but can worsen without regular eye checks.

Proliferative diabetic retinopathy (PDR)

The advanced stage. The body grows new fragile vessels that leak easily. This can cause scar tissue and sometimes retinal detachment.

Diabetic Maculopathy

Without treatment, PDR can lead to serious sight loss. Diabetic macular oedema (DMO) can happen at any stage. Fluid builds in the macula, the area used for sharp vision. It can blur vision and needs monitoring or treatment.

What are the stages of diabetic retinopathy?

Diabetic retinopathy builds up over time. The longer you have diabetes and the harder it is to control blood sugar, the more likely it will progress.

1. Background retinopathy

Earliest stage. Small bulges form in the eye’s blood vessels. You may not notice symptoms, but an eye test can detect it.

2. Pre‑proliferative retinopathy

More vessels are affected and may block. It often causes no symptoms but needs watching.

3. Proliferative retinopathy

New weak vessels grow and can bleed. This stage has a higher risk of major vision loss.

4. Diabetic macular oedema

Can happen at any stage. Fluid leaks into the macula, causing swelling and blurred vision.

Regular diabetes eye checks help detect it early.

What causes diabetic retinopathy?

Diabetic retinopathy happens when high blood sugar harms the small vessels in the retina, the part of the eye that senses light and sends messages to the brain. Over time, these vessels can swell, leak or block. This cuts oxygen supply to the retina and can affect vision. Poor blood sugar control raises the risk. High blood pressure, cholesterol and years living with diabetes also play a role.

What the experts say about diabetic retinopathy

Our expert optometrists regularly see patients with signs of diabetic retinopathy, often before they’ve noticed anything themselves. Here, one of our optometrists shares how they spot early changes, what happens during an eye test, and how they work with patients to protect their sight.

Sometimes it’s just about closer monitoring. Other times, it’s helping someone understand what their results mean and referring them for specialist care. Whatever the stage, we’re here to guide you every step of the way.

Who is most at risk of diabetic retinopathy?

Anyone with diabetes, type 1 or type 2, can get diabetic retinopathy. Risk goes up the longer you’ve had diabetes, especially if blood sugar has been hard to manage.

Other risk factors include:

High blood pressure that puts strain on eye blood vessels
High cholesterol that reduces oxygen supply
Smoking that lowers circulation and increases damage
Pregnancy, when hormone changes can increase risk
Missing eye checks, as early signs are easy to miss

Regular diabetes eye checks are important. Keeping blood sugar, blood pressure and cholesterol in check and having yearly eye checks lowers risk.

How is diabetic retinopathy tested and diagnosed?

At your eye test, your optometrist will ask about your eye health, any changes, and how your diabetes is being managed. This helps us check your risk and choose the right tests.

We’ll do several painless checks for early signs:

Visual acuity test

You’ll read a letter chart letter chart so we can check your vision and look for changes.

Tonometry

Measures the pressure in your eye.

Dilated eye exam

Drops may be used to widen your pupils so we can clearly see the retina and optic nerve.

Digital retinal photography

A quick scan takes detailed pictures of the back of your eye.

OCT scan

Creates 3D images of the retina to check for swelling or damage. If we find signs, we’ll explain what’s happening and refer you for specialist care if needed. These checks are quick and help protect your sight.

Treatment for diabetic retinopathy

If diabetic retinopathy is found early, you might not need treatment right away, but regular eye tests will help monitor it.

If you’ve noticed blurred vision, floaters or changes in your sight, book an eye test as soon as you can.

The right treatment will depend on the stage and type of retinopathy. Your eye specialist will explain your options and answer your questions.

How is diabetic retinopathy treated?

You might be referred to an eye specialist for one of the following:

Laser treatment

Laser treatment seals leaking blood vessels and stops new ones from growing to help protect the retina and prevent further vision loss.

There are two main types:

Focal laser photocoagulation – targets a specific affected area
Pan‑retinal photocoagulation – treats the wider peripheral retina

Laser treatment is done under local anaesthetic at an outpatient clinic. Your pupils will be widened with drops, and a special lens will keep your eye open. You may feel a mild pricking sensation in some areas, but most people don’t find it painful. The whole procedure usually takes 20–40 minutes.

After treatment, your vision may be blurry for a few hours, and you’ll be sensitive to light, so bring sunglasses and arrange for someone to drive you home. It may take several sessions and a few months to see the full benefit.

Eye injections

Injections, delivering anti‑VEGF drugs, help reduce swelling in the macula and stop abnormal blood vessel growth. Sometimes steroids are used instead.

The injection is given under local anaesthetic, using a fine needle. You may need monthly injections at first, with fewer as your condition stabilises.

Side effects can include floaters, mild irritation, or watery eyes, but the treatment is safe and can improve vision in many people.

Eye surgery (vitrectomy)

In more advanced cases, surgery may be needed to remove blood or scar tissue from inside the eye. This is called a vitrectomy.

It’s usually done under local anaesthetic and sedation. You’ll go home the same day or the next, wearing an eye patch for a few days. It can take several months for your vision to settle afterwards.

Risks like infection or retinal detachment are rare. The surgery is considered safe and helps improve or stabilise vision in most patients.

Is diabetic retinopathy preventable?

You can’t always prevent diabetic retinopathy, but there’s a lot you can do to lower your risk and slow it down. Managing your diabetes well and having regular eye checks makes a real difference.

1. Keep your blood sugar in check.

The better your control, the lower the risk of damage to the blood vessels in your eyes.

2. Manage your blood pressure.

High pressure puts extra strain on the delicate vessels in the retina.

3. Watch your cholesterol.

Raised cholesterol can affect blood flow to your eyes.

4. Don’t smoke.

Smoking reduces circulation and speeds up damage to blood vessels.

5. Go to all your diabetes check‑ups.

This includes foot checks, blood tests and other health reviews.

6. Get regular eye checks.

A yearly diabetes eye test or eye screening helps spot any changes early, when treatment works best.

Even if you already have early signs of diabetic retinopathy, these steps can still help stop it getting worse.

Driving and diabetic retinopathy

Diabetic retinopathy, especially in later stages, can affect your ability to drive safely. Early stages often leave vision unaffected, but advanced stages can cause black spots, blurry sight or narrow side vision, all of which make driving harder.

Here’s what to know:

Visual impact

Changes to your sight can affect reaction time, reading signs and judging distance, especially at night.

Driving standards

Check with Waka Kotahi NZTA about driving vision rules. If your sight doesn’t meet the standards, you must stop driving and inform them. You also need to tell them if you’ve had laser treatment in both eyes, have proliferative retinopathy or are told to stop after a screening or hospital visit.

Ophthalmologist advice

If you’re unsure, speak to your optometrist or eye doctor. They’ll check your vision and advise you. Support and next steps If you can’t drive, use public transport, taxis or local help.

Common questions: Diabetic retinopathy

Did you know?

AA Members are entitled to a free eye test (valued at $60), once every two years. Remember to present your AA Membership card in‑store.

Book an appointment See more eye conditions

Written with care and checked for accuracy

Dr Joseph Paul

B.Optom PhD

Dr Joseph Paul studied optometry at the University of Melbourne, graduating in 2011. He then completed a PhD in retinal structure and function at the University of Melbourne and a post‑doctoral position in optic nerve bioenergetics at the Centre for Eye Research Australia.

Alongside this work, Dr Joseph has practised in a wide range of public, private and corporate optometry practices across Victoria over the past decade. He is Head of Professional Services at Specsavers Australia and New Zealand.

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