Did you know that diabetes is the primary cause of preventable blindness in adults?[1] It’s quite a shocking fact, but it just goes to show how important it is to consider your eye health when you have type 2 diabetes. The truth is that your blood glucose levels impact the way your whole body works, which is why it’s so important for everyone to manage their blood sugar, especially people living with type 2 diabetes. One thing that doesn’t often get talked about though is how consistently high blood sugar levels can affect your eyes. This might be because it takes several years to reach a stage where it significantly damages your eyesight [2] but like a lot of health risks associated with diabetes, being aware of the symptoms and managing them early is the key to maintaining healthy eyes and preventing sight loss. 

Diabetes is the primary cause of preventable sight loss in the UK

Diabetes UK

If you have type 2 diabetes, you may already be thinking about times when you’ve noticed your vision go blurry. That’s because periods of blurred vision are symptomatic of a spike in your blood glucose levels. When you have high blood sugar levels, your lens can swell which affects your eyesight. This most likely fades once your blood sugar level regulates, and your eyesight returns to normal.[3] If your eyesight doesn’t go back then this could be a sign that there’s a more serious issue at play.

The term ‘diabetic retinopathy’ is used to describe a range of problems in the eye that are caused by diabetes. They’re all caused by high blood glucose which leads to elevated blood pressure which, in turn, can damage or block your blood vessels. The blood vessels in your eyes have an important job to do: they provide blood to your retina, which is the part of the eye that controls your sight. When they get damaged, this has a direct and long-term impact on your vision.[2] 

The three stages of diabetic retinopathy

If you have type 2 diabetes and live in the UK, you're eligible for an annual NHS eye screening, which will monitor your eye health and the development of any diabetic retinopathy. This screening is considered a vital diabetes check, so if you haven't been attending them or been offered one, we'd urge you to make an appointment as soon as possible. The results of the screening will refer to diabetic retinopathy in four different stages.

‍Stage one: background retinopathy

The first stage of diabetic retinopathy is known as background retinopathy.[1] While your eyesight hasn’t yet been affected it that doesn’t mean everything is fine, but rather that you should be actively thinking about how to prevent things from getting any worse (which we’ll cover later on!). At this stage, the blood vessels in your retinas are developing microaneurysms, which are really small lumps. The trickiet thing about stage one diabetic retinopathy is that you probably won’t notice any obvious symptoms, which is why regular eye screenings are so important for anyone with diabetes. 

‍Stage two: non-proliferative retinopathy

If any background retinopathy goes untreated, the next stage of the disease is referred to as non-proliferative retinopathy.[1] This means that the damage to your eyes has become serious and is probably causing bleeding in the retina. If your eye damage gets to this stage, you’ll almost definitely be noticing some changes in your vision. Things, like trouble seeing in the dark, blurriness, or even floating shapes, could all be signs of severe diabetic retinopathy. Sometimes your vision might become dimmed, as if you’re wearing sunglasses all the time.[1] You might also be experiencing pain or spot visible redness when you look in the mirror.[4] If you have type 2 diabetes and you recognise any of these symptoms, get in touch with your care team who will likely offer you more frequent screenings to monitor your eye health. 

‍Stage three: proliferative retinopathy

At this point, you’re at a very high risk of losing your eyesight. The impact of consistently high blood pressure and blood sugar levels means that scar tissue and new blood vessels will be forming on your retinas. If you enter stage three of eye disease, you’ll need treatment to prevent advancing your sight loss which could involve surgery, laser treatment, or injections.[5]

Other eye problems to be aware of

There’s another type of diabetic retinopathy which is a little different from the three stages above, known as diabetic maculopathy. While those first three can affect all parts of the retina, diabetic maculopathy is specific to the middle part of your retina, the macula, which is responsible for your central vision. A build-up of fluid in this part of your eye, known as a diabetic macula oedema, can seriously disrupt your day-to-day life as it could prevent you from doing things like driving or reading.[6] 

Diabetic retinopathy is the development of sight loss directly related to diabetes, but people living with type 2 diabetes are also at an increased risk of developing other eye problems. Having diabetes can mean you’re one and a half times more likely to develop glaucoma–which is when fluid builds up in your eyes–and two times as likely to develop cataracts. Cataracts can cause your vision to go cloudy. Both glaucoma and cataracts, if left untreated, can lead to blindness.[1]

Fortunately, diabetic eye screenings will help identify all these problems early and help protect you from diabetic retinopathy, cataracts, and glaucoma.

Reducing your risk of developing diabetic retinopathy 

It all sounds a bit scary, but if you’re on the path to managing, or even reversing, your type 2 diabetes then you’re already doing all the right things to reduce your risk of eye damage. It’s something you’ll hear a lot, but the single most useful thing you can do to take care of your body—and your eyes!—as someone with type 2 diabetes, is to monitor and regulate your blood sugar levels. It’s definitely easier said than done, but here’s some food for thought on reducing your risk of eye disease:

Watch your blood sugar, blood pressure, and cholesterol levels

Monitoring your levels regularly will help you notice when things change, for better or worse. High blood glucose and high blood pressure are the two big things to look out for when it comes to your eye health. A quick guide for what you should be seeing is:

If you check your blood sugar at home, it should be 4 to 7mmol/l, and you should try and check at different times throughout the day

• GP blood sugar tests take an average from the past few weeks and most people with diabetes should be looking for 48mmol/mol or 6.5% 
• As someone with diabetes you should aim for your blood pressure reading to be no more than 140.80mmHg, and no less than 130/80mmHg but if you’ve been given alternative guidance by your GP, you should follow that  
• A healthy total cholesterol level is below 4mmol/l and can be measured with a blood test by your GP [7]

Get regular screenings

As someone living with type 2 diabetes, regular eye screenings are a crucial part of managing your health. Even if you think you have things under control you should still get tested as the screening could identify a problem before you even know there is one. Early detection means that your treatment options are much more likely to be effective, and it’s important to remember that stage one diabetic retinopathy very rarely causes symptoms, so by the time you notice it it’s likely to be quite advanced. That’s why it’s so important to have regular check-ups.

Live a healthy lifestyle

Making positive changes to your diet, habits, and routine can have a huge impact on managing your type 2 diabetes, and that includes your eye health too. 

Eating a healthy, balanced diet, and in particular cutting down on sugary foods like junk food, is the single most effective way of managing your blood sugar levels. It’s not always something you can just switch on, but slowly establishing better food habits will really help in the long run.

Other ways to make a positive difference are things like introducing exercise into your routine, keeping within recommended alcohol limits, and stopping smoking, if you smoke. 

‍Managing your type 2 diabetes cares for your eyes

Potential sight loss is an important thing to be aware of for anyone living with type 2 diabetes. The real danger is that diabetic retinopathy can become quite advanced before its symptoms are noticeable. This means that, even if you’re managing your diabetes, it’s really important to get regular eye screenings, and if you notice changes to your vision such as problems seeing in the dark, floating shapes or blurriness, you should contact your GP straight away. It’s important to note that those symptoms may not be diabetic retinopathy, but it’s good to get them checked out regardless because they probably mean that something’s up. 

On the plus side, keeping your eyes healthy when you’re living with type 2 diabetes comes in a package deal. By monitoring and maintaining your blood sugar levels and blood pressure, and by making healthy life choices such as upping the exercise and reducing your sugar intake, you’re automatically also taking care of your eyes. Diabetic retinopathy is caused by consistently high blood glucose levels and high blood pressure, so by keeping a handle on those, you’re doing what you need to do to prevent sight loss.

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