Diabetic retinopathy

Published by Health Professional

on Wednesday, March 22nd 2023

DiabetesEye HealthTrending Health Topics

Diabetic retinopathy is a complication of diabetes caused by high blood sugar levels damaging the back of the eye (retina). It can cause blindness if left undiagnosed and untreated.

However, it usually takes several years for diabetic retinopathy to reach a stage that could threaten your sight.

To minimise the risk of this happening, people with diabetes should:

  • ensure they control their blood sugar levels, blood pressure and cholesterol
  • attend diabetic eye screening appointments – annual screening is offered to all people with diabetes aged 12 and over to pick up and treat any problems early on

How diabetes can affect the eyes

The retina is the light-sensitive layer of cells at the back of the eye that converts light into electrical signals. 

The signals are sent to the brain, turning them into the images you see.

The retina needs a constant supply of blood, which it receives through a network of tiny blood vessels.

Over time, a persistently high blood sugar level can damage these blood vessels in 3 main stages:

  • background retinopathy – tiny bulges develop in the blood vessels, which may bleed slightly but do not usually affect your vision
  • pre-proliferative retinopathy – more severe and widespread changes affect the blood vessels, including more significant bleeding into the eye
  • proliferative retinopathy – scar tissue and new blood vessels, which are weak and bleed easily, develop on the retina; this can result in some loss of vision

However, if a problem with your eyes is picked up early, lifestyle changes and treatment can stop it from worsening.

Am I at risk of diabetic retinopathy?

Anyone with type 1 diabetes or type 2 diabetes is potentially at risk of developing diabetic retinopathy.

You’re at greater risk if you:

  • have had diabetes for a long time
  • have a persistently high blood sugar (blood glucose) level
  • have high blood pressure
  • have high cholesterol
  • are pregnant
  • are of Asian or Afro-Caribbean background

By controlling your blood sugar, blood pressure and cholesterol levels, you can reduce your chances of developing diabetic retinopathy.

Symptoms of diabetic retinopathy

You will not usually notice diabetic retinopathy in the early stages, as it does not tend to have any obvious symptoms until it’s more advanced.

However, early signs of the condition can be picked up by taking photographs of the eyes during diabetic eye screening.

Contact your doctor or diabetes care team immediately if you experience the following:

  • gradually worsening vision
  • sudden vision loss
  • shapes floating in your field of vision (floaters)
  • blurred or patchy vision
  • eye pain or redness
  • difficulty seeing in the dark

These symptoms do not necessarily mean you have diabetic retinopathy, but getting them checked out is important. 

Do not wait until your next screening appointment.

Reduce your risk of diabetic retinopathy

You can reduce your risk of developing diabetic retinopathy or help prevent it from getting worse by:

  • controlling your blood sugar, blood pressure and cholesterol levels
  • taking your diabetes medicine as prescribed
  • attending all your screening appointments
  • getting medical advice quickly if you notice any changes to your vision
  • maintaining a healthy weight, eating a healthy, balanced diet, exercising regularly and stopping smoking

Treatments for diabetic retinopathy

Treatment for diabetic retinopathy is only necessary if screening detects significant problems that mean your vision is at risk.

If the condition has not reached this stage, the above advice on managing your diabetes is recommended.

The main treatments for more advanced diabetic retinopathy are:

  • laser treatment
  • injections of medication into your eyes
  • an operation to remove blood or scar tissue from your eyes

Diabetic retinopathy develops in stages over time.

If you’re diagnosed with diabetic retinopathy after diabetic eye screening, lifestyle changes and treatment can reduce the chances of the problem progressing.

The main stages of diabetic retinopathy are described below. You will not necessarily experience all of these.

Stage 1: background retinopathy

This means that tiny bulges (microaneurysms) have appeared in the blood vessels in the back of your eyes (retina), which may leak small amounts of blood. This is very common in people with diabetes.

At this stage:

  • your sight is not affected, although you’re at a higher risk of developing vision problems in the future
  • you do not need treatment, but you’ll need to take care to prevent the problem from getting worse
  • the chances of your sight getting worse are higher if both of your eyes are affected

Stage 2: pre-proliferative retinopathy

This means that more severe and widespread changes are seen in the retina, including bleeding into the retina.

At this stage:

  • there’s a high risk that your vision could eventually be affected
  • you’ll usually be advised to have more frequent screening appointments every 3, 6, 9 or 12 months to monitor your eyes

Stage 3: proliferative retinopathy

This means that new blood vessels and scar tissue have formed on your retina, which can cause significant bleeding and lead to retinal detachment, where the retina pulls away from the back of the eye.

At this stage:

  • there’s a very high risk you could lose your vision
  • treatment will be offered to stabilise your vision as much as possible, although it will not be possible to restore any vision you’ve lost

Diabetic maculopathy

In some cases, the blood vessels in the part of the eye called the macula (the central area of the retina) can also become leaky or blocked. 

This is known as diabetic maculopathy.

If this is detected:

  • there’s a high risk that your vision could eventually be affected
  • you may be advised to have more frequent specialised testing to monitor your eyes
  • you may be referred to a hospital specialist to discuss treatments that can help stop the problem from getting worse

Which stage am I at?

If you’ve had a diabetic eye screening test, follow up with your doctor to find out if you  have one of the following:

  • No retinopathy – this means no signs of retinopathy were found, and you should attend your next screening appointment in 12 months
  • Background retinopathy – this means you have stage 1 retinopathy and should attend your next screening appointment in 12 months; you may be seen sooner if your diabetes is not well controlled
  • degrees of referable retinopathy – this means you have stage 2 or 3 retinopathy or diabetic maculopathy and should have more frequent tests or be referred to a specialist about possible treatments

Diabetic retinopathy usually only requires specific treatment when it reaches an advanced stage, and there’s a risk to your vision.

It’s typically offered if diabetic eye screening detects stage 3 (proliferative) retinopathy or if you have symptoms caused by diabetic maculopathy.

Managing your diabetes

The most important part of your treatment is to keep your diabetes under control.

In the early stages of diabetic retinopathy, controlling your diabetes can help prevent vision problems from developing.

In the more advanced stages, when your vision is affected or at risk, keeping your diabetes under control can help prevent the condition from worsening.

Treatments for advanced diabetic retinopathy

For diabetic retinopathy that is threatening or affecting your sight, the main treatments are:

  • laser treatment – to treat the growth of new blood vessels at the back of the eye (retina) in cases of proliferative diabetic retinopathy and to stabilise some cases of maculopathy
  • Eye injections – to treat severe maculopathy that’s threatening your sight
  • Steroid eye implants – to treat severe maculopathy if eye injections are not suitable or have not worked for you
  • Eye surgery – to remove blood or scar tissue from the eye if laser treatment is not possible because retinopathy is too advanced

Laser treatment

Laser treatment treats new blood vessels at the back of the eyes in the advanced stages of diabetic retinopathy.

This is done because the new blood vessels tend to be very weak and often cause bleeding into the eye.

Treatment can help stabilise the changes in your eyes caused by your diabetes and stop your vision from worsening, although it will not usually improve your sight.

Laser treatment:

  • involves shining a laser into your eyes – you’ll be given local anesthetic drops to numb your eyes; eye drops are used to widen your pupils, and special contact lenses are used to hold your eyelids open and focus the laser onto your retina
  • normally takes around 20 to 40 minutes
  • is usually carried out on an outpatient basis, which means you will not need to stay in the hospital overnight
  • may require more than 1 visit to a laser treatment clinic
  • is not usually painful, although you may feel a sharp pricking sensation when certain areas of your eye are being treated

Side effects

After treatment, you may have some side effects for a few hours.

These can include:

  • blurred vision – you will not be able to drive until this passes, so you’ll need to arrange for a friend or relative to drive you home or take public transport
  • increased sensitivity to light – it might help to wear sunglasses until your eyes have adjusted
  • aching or discomfort – over-the-counter painkillers, such as paracetamol, should help

Possible complications

You should be told about the risks of treatment in advance.

Potential complications include:

  • reduced night or peripheral (side) vision – some people may have to stop driving as a result of this
  • bleeding into the eye or objects floating in your vision (floaters)
  • being able to “see” the pattern made by the laser on the back of your eye for a few months
  • a small but permanent blind spot close to the centre of your vision

Get medical advice if you notice that your sight gets worse after treatment.

Eye injections

In some cases of diabetic maculopathy, anti-VEGF injections may be given directly into your eyes to prevent new blood vessels from forming at the back of the eyes.

The main medicines used are ranibizumab (Lucentis) and aflibercept (Eylea).

These can help stop the problems in your eyes from worsening and may also improve your vision.

During treatment:

  • the skin around your eyes will be cleaned and covered with a sheet
  • small clips will be used to keep your eyes open
  • you’ll be given local anaesthetic drops to numb your eyes
  • a very fine needle is carefully guided into your eyeball, and the injection is given

The injections are usually given once a month, to begin with. Once your vision stabilises, it’ll be stopped or given less frequently.

Injections of steroid medication may sometimes be given instead of anti-VEGF injections or if the anti-VEGF injections do not help.

Risks and side effects

Possible risks and side effects of anti-VEGF injections include:

  • eye irritation or discomfort
  • bleeding inside the eye
  • floaters or a feeling of having something in your eye
  • watery or dry, itchy eyes

There’s also a risk that the injections could cause blood clots to form, leading to a heart attack or stroke.

This risk is small but should be discussed before you consent to treatment. The main risk with steroid injections is increased pressure inside the eye.

Steroid implants

Suppose you cannot have anti-VEGF injections, or they have not worked for you. In that case, you may be offered an eye implant called an intravitreal implant (Ozurdex) containing a steroid medicine called dexamethasone.

This tiny implant is injected into your eye using a special applicator. You’ll be given a local anaesthetic first to numb your eye.

The implant slowly releases dexamethasone over a few months. This reduces swelling in your eye and can help to improve your eyesight.

The implant eventually dissolves, so it does not need to be removed.

Risks and side effects

Possible risks and side effects of having the implant include:

  • headaches
  • increased pressure inside the eye
  • cataracts
  • bleeding in your eye
  • eye pain
  • problems with your eyesight

Side effects usually get better after a few days. Speak to your treatment team if you have eye pain or changes to your eyesight.

Eye surgery

Surgery may be carried out to remove some vitreous humour from the eye. This transparent, jelly-like substance fills the space behind the eye’s lens.

The operation, known as vitreoretinal surgery, may be needed if:

  • a large amount of blood has collected in your eye
  • there’s extensive scar tissue that’s likely to cause or has already caused retinal detachment

During the procedure, the surgeon will make a small incision in your eye before removing some of the vitreous humour, removing any scar tissue and using a laser to prevent further deterioration in your vision.

Vitreoretinal surgery is usually carried out under local anaesthetic and sedation. This means you will not experience any pain or be aware of the surgery.

After the procedure

You should be able to go home on the same day or the day after your surgery.

You may need to wear a patch over your eye for the first few days. This is because activities such as reading and watching television can quickly tire your eye.

You may have blurred vision after the operation. This should improve gradually, although it may take several months for your vision to return to normal fully.

Your surgeon will advise you about any activities you should avoid during your recovery.

Risks and side effects

Possible risks of vitreoretinal surgery include:

  • developing a cataract
  • further bleeding into the eye
  • retinal detachment
  • fluid build-up in the cornea (the outer layer at the front of the eye)
  • infection in the eye

There’s also a small chance that you will need further retinal surgery afterwards. Your surgeon will explain the risks to you.

Prevention

You can reduce your risk of developing diabetic retinopathy, or help stop it from worsening by controlling your blood sugar levels, blood pressure and cholesterol levels.

This can often be done by making healthy lifestyle choices, although some must also take medication.

Healthy lifestyle

A few lifestyle changes can improve your general health and reduce your risk of developing retinopathy.

These include:

  • eating a healthy, balanced diet – in particular, try to cut down on salt, fat and sugar
  • losing weight if you’re overweight – you should aim for a BMI of 18.5-24.9; use the BMI calculator to work out your BMI
  • exercising regularly – aim to do at least 150 minutes of moderate-intensity activity, such as walking or cycling, a week; doing 10,000 steps a day can be a good way to reach this target
  • stopping smoking if you smoke
  • not exceeding the recommended alcohol limits – men and women are advised not to drink more than 14 alcohol units a week regularly

You may also be prescribed medication to help control your blood sugar level (such as insulin or metformin), blood pressure (such as ACE inhibitors) and cholesterol level (such as statins).

Know your blood sugar, blood pressure and cholesterol levels

It can be easier to control your blood sugar, blood pressure, and cholesterol levels if you monitor them regularly and know their levels.

The lower you can keep them, the lower your chances of developing retinopathy are.

Your diabetes care team can let you know your target levels.

Blood sugar

If you check your blood sugar level at home, it should be 4 to 7mmol/l. The level can vary throughout the day, so check it at different times.

The check at your doctor’s surgery measures your average blood sugar level over the past few weeks. You should know this number, as it is the most important measure of your diabetes control. 

It’s called HbA1c; for most people with diabetes, it should be around 48mmol/mol or 6.5%.

Read about treating type 1 diabetes and treating type 2 diabetes.

Blood pressure

You can ask for a blood pressure test at your doctor’s surgery or buy a blood pressure monitor at home. Blood pressure is measured in millimetres of mercury (mmHg) and is given as 2 figures.

If you have diabetes, you’ll normally be advised to aim for a blood pressure reading of no more than 140/80mmHg, or less than 130/80mmHg if you have diabetes complications, such as eye damage.

Cholesterol

Your cholesterol level can be measured with a simple blood test carried out at your doctor’s surgery. The result is given in millimoles per litre of blood (mmol/l). A healthy total cholesterol level is below 4mmol/l.

Regular screening

Even if you think your diabetes is well controlled, it’s still important to attend your annual diabetic eye screening appointment, as this can detect signs of a problem before you notice anything is wrong.

Early detection of retinopathy increases the chances of treatment being effective and stopping it from getting worse.

You should also contact your doctor or diabetes care team immediately if you develop any problems with your eyes or vision, such as:

  • gradually worsening vision
  • sudden vision loss
  • shapes floating in your field of vision (floaters)
  • blurred vision
  • eye pain or redness
  • difficulty seeing in the dark

These symptoms do not necessarily mean you have diabetic retinopathy, but it’s important to get them checked out straight away.