Diabetes is a lifelong condition and can cause several health complications it can lead to problems in various parts of the body. Your eyes are one part of your body that can be affected.

How can diabetes affect my eyes?

Not everyone who has diabetes develops a related eye condition, so it’s possible that your diabetes won’t cause any changes to your vision. However, when diabetes does affect the eyes, it can do so in other ways. These include:

An unstable glasses prescription

The changes in blood sugar levels caused by diabetes can affect the natural lens inside your eye making your vision become more blurred or more variable throughout the day or from day to day. This can make your glasses prescription variable and unreliable. As your blood glucose becomes better managed, this variation in your vision will settle down.

Diabetic retinopathy

Over time, diabetes can affect the network of blood vessels supplying the retina at the back of the eye, and this damage changes how well the retina works. This is known as diabetic retinopathy. There are different stages of diabetic retinopathy and how your vision is affected will depend on the severity of the changes to the retinal blood vessels and the area of the retina that is involved.

Cataract

Diabetes can cause the lens in your eye to become cloudy. This condition is known as a cataract. If you have diabetes, you’re more likely to develop a cataract, and at an earlier age than might be expected in someone without diabetes. Cataracts can be removed with surgery.

Glaucoma

Some people with diabetes may develop glaucoma, an eye condition where the pressure inside the eye damages the optic nerve at the back of the eye. Glaucoma can be treated with eye drops, laser treatment or surgery if necessary.

Other associated eye conditions

There may be an increased risk of other eye conditions when you have diabetes including those that affect the cornea, eye muscle problems or retinal vessel occlusion (a blocked retinal blood vessel).

What are the stages of diabetic retinopathy?

A healthy retina needs healthy blood vessels to deliver oxygen and nutrients and remove its waste products. The high blood glucose levels caused by diabetes can damage the blood vessels in the retina, so that they can become blocked, they leak, or they grow incorrectly. This can lead to complications in the eye known as diabetic retinopathy. There are different types of retinopathy:

• Background diabetic retinopathy: Background retinopathy does not usually affect your sight, but your eyes will need to be monitored carefully to make sure your retinopathy doesn’t progress and get worse.
• Proliferative diabetic retinopathy: If background retinopathy gets worse, many of the retinal blood vessels become damaged or blocked. When these changes happen over a large area of your retina, it will have an insufficient blood supply. This is known as ischaemia. As retinal ischaemia increases, the body tries to make up for the lack of oxygen by growing new blood vessels on the retinal surface or into the vitreous gel. Unfortunately, these new vessels are weak, and they bleed very easily. Ischaemia can damage the retina, causing areas of sight loss where the retina cannot work properly.
• Diabetic maculopathy and diabetic macular oedema: When diabetic retinopathy affects your macula, it’s known as diabetic maculopathy. If the blood vessels near the macula are leaky, fluid can build up and cause macular swelling. This is called diabetic macular oedema (DMO) and it can cause vision to be blurred and distorted, as well as making colours appear washed out.

How can I reduce the risk of developing retinopathy?

If your blood sugar levels are continually high, there’s a greater chance the blood vessels in your eyes will become damaged and that more serious diabetic retinopathy will develop over time. There is also some evidence that for some people, a sudden and intensive reduction in a previously high blood sugar level can also cause problems, so speak to your diabetic medical team if you have any questions about how best to manage your condition. However, the more consistently your blood sugars stay within your target range, the lower your risk of developing serious problems with your eyes. Looking after other aspects of your health is also important, such as managing your blood pressure and cholesterol. There are things you can do to help control your risk of developing retinopathy, or stop it from getting worse. These include:

• Doing your best to keep your blood glucose level in your target range as consistently as you can.
• Controlling your blood pressure to keep it within your target range.
• Controlling your cholesterol levels.
• Keeping as fit as you can with regular exercise and a healthy diet to help maintain a healthy weight.
• Giving up smoking. Nerve damage (known as neuropathy), kidney disease and cardiovascular disease are more likely in smokers with diabetes. Smoking increases your blood pressure and raises your blood sugar level, which makes it harder to control your diabetes.
• Attending regular diabetic eye screening appointments as advised. Early detection and treatment will protect your sight.

Some factors that you cannot control can increase the risk of developing retinopathy. These include the length of time you’ve had diabetes and your age, as you’re more likely to develop diabetes as you get older. If you’re pregnant, you’re more at risk if you already have diabetes or have had gestational diabetes before.

If you or your family are from India, Pakistan, Bangladesh or Sri Lanka (South Asian communities) or from an African-Caribbean background, you’re more likely to get type 2 diabetes. The factors behind this aren’t fully understood but are thought to involve insulin problems, genetics, diet, and lifestyle.

How can diabetic retinopathy be treated?

Diabetic retinopathy can be treated with a laser. This is known as laser photocoagulation. The laser used to treat proliferative diabetic retinopathy treats large areas of the edge of the retina (peripheral retina) and is known as pan-retinal photocoagulation (PRP). This treatment is given to prevent further sight-threatening complications.

If your maculopathy causes diabetic macular oedema (DMO) which does not affect the centre of the macula, laser treatment can be given in some cases as a targeted treatment to a small, localised area of the macula.

Laser treatment does not make your sight better; its aim is to protect your vision from becoming a lot worse.

How is diabetic macular oedema (DMO) treated?

The very centre of your macula is called the fovea, and if your DMO doesn’t affect this tiny area of the retina, laser treatment can be used to reduce the macular swelling that is present to try to prevent any further blurring of your central vision.

However, as the fovea is a very delicate part of the macula, it cannot be treated directly with the laser. If you have DMO that does affect the fovea, your eye may benefit from treatment with an injection instead. There are a range of different drugs which can be used to treat central DMO. These include:

Anti-VEGF injections

Anti-VEGF injections are a common treatment for central DMO. Anti-VEGF stands for anti-vascular endothelial growth factor, and it is given as an injection into the eye.

Anti-VEGF drugs work by reducing leakiness of blood vessels and stopping new leaky blood vessels from growing. They can also help the fluid to be reabsorbed, reducing your macular oedema, and this can improve vision for some people.

Coping

It’s completely understandable to be upset when you are diagnosed with an eye condition that’s related to your diabetes and it’s normal to find yourself worrying about the future and how you will cope. We can support you at every step, putting you in touch with the advisors you need from any of our supportive teams – just get in touch with our Sight Loss Advice Service.