How Could Diabetes Affect Your Eyes?

Our eyes are endlessly impressive organs, but the fact is, they don’t exist on their own. They are just one part of a complex system consisting of various nerves, neurons, and other organs, including the brain. And they are also linked to other parts and systems in the body. This means that, when something isn’t quite right in another part of your body, your eyes may also be affected. One such condition is diabetes.

Diabetes is a common condition that causes blood sugar levels to become too high. This is the result of low levels of insulin, the hormone that helps turn food into energy and controls blood sugar levels. This deficiency can lead to a number of complications, but many people don’t realise that diabetes can also affect your eye health. For example, diabetes is often associated with an eye condition known as diabetic retinopathy.

What is Diabetic Retinopathy?

The lack of insulin associated with diabetes can lead to a build-up of glucose in the blood. This can affect blood vessels all over the body – including the eyes. In fact, as the eyes have some of the smallest blood vessels in the body, they are often among the first areas to be affected.

Our eyes require a constant supply of blood in order to function efficiently. Much of this blood is supplied to the retina – the light-sensitive layer at the back of the eye that sends signals to the brain – via tiny blood vessels. Over time, high blood sugar levels can damage these blood vessels, and eventually the eye. This occurs in three main stages:

  • Background retinopathy – small bulges will develop in the blood vessels. These may begin to bleed slightly but this doesn’t usually affect vision.
  • Pre-proliferative retinopathy – changes to blood vessels become more severe and widespread causing 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 vision loss.

Diabetic retinopathy is a serious eye condition that can cause significant vision loss and even blindness if left uncontrolled.

Diabetic retinopathy may not have any symptoms at first. Therefore, if you have diabetes, it’s important to undergo a comprehensive dilated eye exam at least once a year. Catching it early can help you take steps to protect your vision.

Other implications of high blood sugar on your eyes

Over the long term, however, diabetes can lead to significant vision loss and permanent damage to your eyes – and diabetic retinopathy is not the only potential problem. Elevated blood sugar levels can also cause:

Fluctuating vision

Diabetes can cause swelling in the eye’s lens, leading to blurred vision. As blood sugar levels rise and fall, this can change the shape of the lens, causing temporary vision impairment. As blood sugar levels stabilise (as achieved with effective diabetes treatments), vision will also usually return to normal.

It is therefore important to ensure your blood sugar levels are controlled before having an exam for visual aids such as glasses and contact lenses and for Laser Eye Surgery. This will ensure that your prescription is measured as accurately as possible.

Diabetic macular oedema

Diabetes can cause damage to the macula – the central area of the retina that is responsible for central and detailed vision. We rely on this part of the eye to provide sharp vision for reading, driving and recognising faces.

As fluid begins to accumulate in the macula (caused by leaking blood vessels) over time, central vision can become less sharp. Eventually, this can lead to partial, or even complete, vision loss. This is known as diabetic macular oedema (DME).

There are two main forms of DME:

  • Focal DME – occurs due to abnormalities in the blood vessels in the eye
  • Diffuse DME -occurs due to the widening/swelling of retinal capillaries

It is possible to avoid or reduce the effects of DME by having regular eye exams and controlling blood sugar levels.


Glaucoma can affect anyone – whether or not they have diabetes. However, people with diabetes are at an increased risk of developing the condition. Patients with diabetic retinopathy are also at greater risk of developing glaucoma.

Typically associated with age, glaucoma occurs when there is an excess amount of fluid pressing on the optic nerve – the bundle of nerves that connects the eye to the brain.

In its early stages, glaucoma can have very few symptoms. However, as it advances, you may notice blurred or missing areas in the vision. The exact symptoms you experience depend on the type of glaucoma you have. But whatever the type, they all pose a serious risk to your vision.

Thankfully, this can be avoided if caught early, and there are now several methods of glaucoma treatment that can significantly reduce its effects.


Cataract is another common eye condition that many people experience as they get older. According to the WHO, cataract is the leading cause of blindness and one of the main causes of visual impairment globally.

Cataracts are characterised by the gradual clouding of the eye’s crystalline lens. This occurs over a long period of time – often years – and can eventually cause significant obstruction to vision.

High blood sugar levels can lead to structural changes in the lens, leading to accelerated development of cataracts. As a result, people with diabetes are more likely to develop cataracts at an earlier age than those without diabetes. Thankfully a short surgery can remove the cataract and restore your vision.

Learn more about Cataracts and Cataract Surgery here.

What can I do to protect my eyes?

As outlined in this article, diabetes can have significant implications for your eye health and vision. Thankfully, there are a number of things you can do to safeguard against these complications and prevent the development (or progression) of diabetic eye disease.

Advice from the National Institute of Diabetes suggests “managing your ABCs”: your A1c (testing to measure your average blood sugar levels), blood pressure, and cholesterol. It is also recommended that patients who smoke quit.

The next step is having a comprehensive dilated eye exam at least once every year. Even if you feel your vision is great, many of the above conditions can develop with few to no symptoms. Aside from this, there really is no downside to getting your eyes checked often.

If you have diabetes and have struggled in the past to manage your health, it’s never too late to start. Put the steps above into practice today and give yourself the best chance at maintaining clear and healthy vision for years to come.

If you’d like to learn more about diabetes and eye health, get in touch with one of our friendly clinic coordinators or Book a Consultation today.