Diabetes and how it can affect your eyes

This Diabetes Awareness Month, Spec-Savers promotes the importance of regular eye tests.

Did you know?

Just one in five adults is aware that an optometrist can detect diabetes-related eye conditions, and even diabetes, during an eye exam.

Diabetes is the primary cause of avoidable blindness in adults ages 20 to 74, so it can be overwhelming to be diagnosed with a diabetic eye disease. The good news is that regular testing can detect these conditions before they affect your eyesight, and there are treatments available that can prevent further damage from occurring.

Diabetes is a condition in which the blood glucose level is higher than normal. If blood glucose remains high for prolonged periods of time, this can damage the blood vessels throughout the body, including the eyes, which contain some of the smallest blood vessels in the body. As a result, people with diabetes are at higher risk of developing specific eye conditions.

What are these specific eye conditions?

Blurred vision

High blood glucose levels can cause fluid to build up in the eyes and cause the lens to swell, making it difficult to focus clearly. To correct it, your blood glucose needs to remain in the target range, but it may take as long as three months for your vision to return to normal. It’s important to advise your optometrist if this occurs, so they can check if this is a symptom of a more serious problem.


The natural internal lens of the eye allows it to see and focus on an image. When that lens gets cloudy, it means a cataract has formed and the eye can’t focus like it should. People with diabetes are at greater risk of developing cataracts and are more likely to develop them at a younger age. Symptoms include blurred vision and glare, and surgery is required to replace the cloudy lens with an artificial one.


People with diabetes have double the chance of developing glaucoma compared to people with normal blood glucose levels. Medication can treat open-angle glaucoma, the most common form, by lowering eye pressure, speeding up drainage and reducing the amount of liquid your eye produces.

For less common forms of glaucoma, treatment can include medicine or special eye drops, or surgery or laser treatments to help lower eye pressure.

Neovascular glaucoma

If you have diabetes, you’re also more likely to develop a rare condition called neovascular glaucoma. This causes new blood vessels to grow on the iris, the coloured part of the eye, which block the normal flow of fluid and raise eye pressure. Primary treatment is to reverse the formation of new blood vessels by using laser treatment or an anti-vascular endothelial growth factor (VEGF) injection to reduce the number of blood vessels and reduce eye pressure.

Diabetic retinopathy

The retina is the layer of the eye that detects light which allows us to see. High blood glucose can damage the tiny vessels at the back of the eye which can result in them leaking, leading to a condition called diabetic retinopathy. If unmanaged, over time this condition can lead to gradual vision loss.

People with Type 1 diabetes rarely develop the condition before puberty. In adults, it’s rare unless they’ve had Type 1 diabetes for at least five years. Keeping tight control of your blood glucose will mean you are far less likely to get this condition.

If you have Type 2 diabetes, you may already have signs of eye problems when you’re diagnosed. Control your blood glucose, blood pressure, and cholesterol to slow or prevent the disease, and if you smoke, try to quit.

Diabetic macular oedema

The macula is the part of the eye responsible for sharp, straight-ahead vision, which we use for driving, reading and facial recognition. Diabetes can lead to macular oedema or swelling, which over time can cause sharp vision to deteriorate.

Save your vision

A full annual eye examination can help detect problems early when they’re easier to treat, which could save your vision.

Spec-Savers’ standard consultations now include a separate diabetic screening using non-invasive artificial intelligence imaging technology at no extra cost. With your permission, your screening results are shared with your ophthalmologist and general practitioner, as they are the most important team managing your condition.

It is essential that, as a person with diabetes, you regularly monitor the status of your eyes for any pathological changes as it provides an immediate monitor of how well you are managing your condition, and is the best way to ensure you have clear vision for life.

For more information or to book an eye exam, please visit www.specsavers.co.za.