Blog - Diabetes Information, Symptoms & Diagnoses
What is Diabetic Retinopathy?
Diabetic retinopathy is a complication of type 1 and type 2 diabetes that affects the eyes which can, if left untreated, cause loss of vision or blindness. Diabetic retinopathy can occur if blood sugar levels remain high over an extended period. Without treatment, increasingly high glucose levels can damage blood vessels within the retina¹ (the light-sensitive tissue at the back of each eye), leading to long-term complications.
On average, diabetic retinopathy happens to around 35% of those with type 1 or type 2 diabetes.² It is more common for people who have had diabetes for a long time – around 20% of those who have had diabetes for less than 10 years are affected by the condition versus 76% of those who have had diabetes for two or more decades.² Sadly, diabetic retinopathy is set to be the leading cause of vision loss in many countries.²
Whether you have been recently diagnosed with diabetes or have had type 1 or type 2 diabetes for several years, regular glucose monitoring with Dexcom CGM can look to reduce the risk of diabetic retinopathy and alert you if your glucose numbers become too high or too low so you can act fast.
What are the symptoms of diabetic retinopathy?
There are few diabetic retinopathy symptoms during the early stages of the condition, but they become increasingly apparent as it progresses. Some of the first signs can include slight changes to vision, particularly when looking into the distance or focusing to complete a task.3
Other common warning signs of diabetic retinopathy include¹:
- Spots or dark strings floating in your vision (known as diabetes eye floaters)
- Blurred/fluctuating or double vision
- Dark or empty areas in your vision
- Vision loss
- Eye pain.
However, it is important to note that symptoms of diabetic retinopathy can be broadly similar to other eye conditions, such as macular degeneration (blurred vision that happens as the eye ages) and hypertensive retinopathy (caused by high blood pressure). If you experience any of the above symptoms, contact your family doctor or diabetes specialist as soon as possible.
What are the complications of diabetic retinopathy?
Even if you have diabetes but do not spot any signs of diabetic retinopathy, it is important to visit an ophthalmologist once a year to check your overall eye health and reduce the risk of long-term complications.
Long term complications include⁴:
- Vitreous haemorrhage: new blood vessels in the eye can bleed, impacting vision.
- Detached retina: new, weakened blood vessels can result in the growth of scar tissue and lead the retina to detach. This can cause visual disturbances or vision loss.
- Glaucoma: blood vessels in the iris can cause increased pressure, affecting the circulation of fluid to the eye. This can damage to the optic nerve, which enables images to be sent from the eye to the brain.
- Diabetic blindness: if left untreated, significant damage to the back of the eye can lead to diabetic blindness or vision loss.
What causes diabetic retinopathy?
Diabetic retinopathy is caused by consistent high blood sugar levels that, over time, result in blocked blood vessels within the eye.
To counteract this blockage and improve blood circulation in the retina,⁵ the eye will develop new, abnormal blood vessels on the surface of the eye, but these are weak and prone to bleed. Those with diabetic retinopathy will see their eyesight affected as fluid leaks into the central part of the retina, otherwise known as the macula, leading to long-term damage and significant changes to vision.⁵
Risks factors for diabetic retinopathy
Those with type 1 or type 2 diabetes are at risk of diabetic retinopathy. Additional risk factors can include the following:1,4,5,6
- Duration of diabetes: you are at greater risk of diabetic retinopathy if you have had diabetes for a long time
- Race: racial and ethnic minorities who have higher rates of macro and microvascular complications of diabetes are more susceptible to known risk factors of diabetic retinopathy
- Medical conditions – high blood pressure or high cholesterol levels can place individuals at higher risk
- Pregnancy – becoming pregnant can raise the risk of diabetic retinopathy (this does not include gestational diabetes).
What are the four stages of diabetic retinopathy?
For those with diabetes, changes to eyesight occur over time. There are four key stages to diabetic retinopathy: background retinopathy, non-proliferative retinopathy, proliferative retinopathy and diabetic maculopathy.1
1. Background retinopathy
Background retinopathy is one of the first identifiers of diabetic retinopathy and is characterised by swellings in the walls of blood vessels in the eye, which are known as blebs. Small dots will also appear on the retina, alongside yellow patches of exudates (cells and fluid from the blood).⁷ While those with diabetes ordinarily won’t experience any changes to their vision at this stage, preventative steps should be taken to reduce the risk of the condition advancing.
2. Non-proliferative retinopathy (NPDR)
Non-proliferative diabetic retinopathy (NPDR), or ‘early diabetic retinopathy’, is when the walls of the blood vessels in the retina weaken⁴, leaking blood and fluids. The walls of smaller blood vessels also change in size and diameter, with various swellings and distensions, eventually leading to blood vessel closure and non-perfusion.
3. Proliferative retinopathy (PDR)
Proliferative retinopathy (PDR) is where diabetic retinopathy symptoms have advanced. Blood vessels to the eye have become blocked and damaged over time, leading to the growth (proliferation) of new, weakened and abnormal blood vessels that have a high risk of leakage and bleeding.
4. Diabetic maculopathy
Over a long period, leaking eye vessels can create a build-up of fluid in the centre of the retina (known as the macula), and result in diabetic maculopathy.⁴ Images that are sent from the eye to the brain can become distorted and can lead to an inability to focus.
How to diagnose diabetic retinopathy
Diabetic retinopathy can be diagnosed through an eye exam. If you have diabetes and eye problems, a health professional will assess your medical history and discuss any concerns you have regarding your overall eye health and diabetes management.
A test for diabetic retinopathy involves a health professional looking for changes to your vision, overall ocular structures and the appearance of the retina⁵. During an eye screening the typical steps are5:
- You'll be asked to read letters on a chart.
- Drops are then put in your eyes. The drops make your sight blurry after about 15 minutes.
- When the drops start working, you'll be asked to look into a camera.
- Pictures are taken of the back of your eyes.
You will then need to wait 6 weeks typically for the results.
How to prevent diabetic retinopathy
The here provided information are intended to give a general overview on available information. Please always consult with your family doctor or diabetes specialist for before doing changes to your diabetes management.
Maintaining a healthy blood sugar (glucose) level range through regular glucose monitoring will reduce the risk of diabetic retinopathy. Informing your family doctor of any changes to your eyes and ongoing diabetes management ⁸ will be vital, alongside regular diabetic eye screenings.5,8
Adopting a healthy diet and increasing physical activity to at least 150 minutes each week4 will help to lower blood pressure and cholesterol levels, which can also impact your diabetes and eyesight.3 Additionally, taking essential medications provided by your family doctor to manage your diabetes symptoms4 and quitting smoking will also be advantageous.4
For those who have recently been diagnosed or are looking to review an existing diabetes management plan,3 a haemoglobin A1C (HbA1C) test can be completed by your family doctor which can detail your average blood sugar levels over a three-month period and allow for the development of an individualised plan.
Whatever your age, lifestyle, daily routine or health status, Dexcom CGM has therefore been designed to make type 1 and type 2 diabetes management easier and safer. With accurate9, real-time glucose readings every five minutes, without the need for finger pricks†‡, using Dexcom CGM systems lead to better glycaemic control and HbA1CX and can therefore reduce the risk of long-term complications.10-15
Learn the differences between Dexcom One, G6 and G7 CGM devices for type 1 and type 2 diabetes in order to choose the right continuous glucose monitor for you.
References and Footnotes
† Display devices sold separately. For a list of compatible smart devices, please visit www.dexcom.com/en-GB/compatibility.
‡ Finger pricks are required for diabetes treatment decisions if symptoms or expectations do not match readings
1 NHS. Diabetic Retinopathy. Updated 16 December 2021. Accessed 11 January 2023. NHS.
2 Amoaku, W.M, et al. Diabetic retinopathy and diabetic macular oedema pathways and management : UK Consensus Working Group. Eye. 2020;34(S1) :1–51. Eye.
3 National Eye Institute. Diabetic Retinopathy. Updated 8 July 2022. Accessed 11 January 2023. NEI.
4 Mayo Clinic. Diabetic retinopathy. Published 24 June 2021. Accessed 11 January 2023. Mayo Clinic.
5 American Optometric Association. Diabetic retinopathy. Accessed 11 January 2023. AOA.
6 Barsegian A, et al. Diabetic Retinopathy: Focus on Minority Populations. Int J Clin Endocrinol Metab. 2017;3(1):034-045. Int J Clin Endocrinol Metab.
7 Diabetes.co.uk. Diabetic Retinopathy. Updated 10 June 2022. Accessed 11 January 2023. Diabetes.co.uk.
8 Diabetes UK. Diabetic Retinopathy — Diabetes And Eye Problems. Accessed 11 January 2023. Diabetes.org.uk.
9 Dexcom G6, G7 and Dexcom ONE user guides
10 Šoupal J, et al. Glycemic Outcomes in Adults with T1D Are Impacted More by Continuous Glucose Monitoring Than by Insulin Delivery Method: 3 Years of Follow‐Up from The COMISAIR Study. Diabetes Care. 2020;43:37-43.
11 Beck RW, et al. Effect of continuous glucose monitoring on glycemic control in adults with type 1 diabetes using insulin injections: The DIAMOND randomized clinical trial. JAMA. 2017;317(4):371-378.
12 Aleppo G, et al. The Effect of Discontinuing Continuous Glucose Monitoring in Adults With Type 2 Diabetes Treated With Basal Insulin. Diabetes Care. 2021;44(12):2729-2737.
13 Visser MM, et al. Effect of switching from intermittently scanned to real-time continuous glucose monitoring in adults with type 1 diabetes: 24-month results from the randomised ALERTT1 trial. Lancet Diabetes Endocrinol. 2023;11:96–108
14 Lind M, et al. Sustained Intensive Treatment and Long-term Effects on HbA1c Reduction (SILVER Study) by CGM in People With Type 1 Diabetes Treated With MDI. Diabetes Care. 2021;44(1):141-149.
15 Diabetes Control and Complications Trial (DCCT). Diabetes Care. 1987;10(1):1-19. Doi: 10.2337/diacare.10.1.1
† Display devices sold separately. For a list of compatible smart devices, please visit www.dexcom.com/en-GB/compatibility.
‡ Finger pricks are required for diabetes treatment decisions if symptoms or expectations do not match readings
1 NHS. Diabetic Retinopathy. Updated 16 December 2021. Accessed 11 January 2023. NHS.
2 Amoaku, W.M, et al. Diabetic retinopathy and diabetic macular oedema pathways and management : UK Consensus Working Group. Eye. 2020;34(S1) :1–51. Eye.
3 National Eye Institute. Diabetic Retinopathy. Updated 8 July 2022. Accessed 11 January 2023. NEI.
4 Mayo Clinic. Diabetic retinopathy. Published 24 June 2021. Accessed 11 January 2023. Mayo Clinic.
5 American Optometric Association. Diabetic retinopathy. Accessed 11 January 2023. AOA.
6 Barsegian A, et al. Diabetic Retinopathy: Focus on Minority Populations. Int J Clin Endocrinol Metab. 2017;3(1):034-045. Int J Clin Endocrinol Metab.
7 Diabetes.co.uk. Diabetic Retinopathy. Updated 10 June 2022. Accessed 11 January 2023. Diabetes.co.uk.
8 Diabetes UK. Diabetic Retinopathy — Diabetes And Eye Problems. Accessed 11 January 2023. Diabetes.org.uk.
9 Dexcom G6, G7 and Dexcom ONE user guides
10 Šoupal J, et al. Glycemic Outcomes in Adults with T1D Are Impacted More by Continuous Glucose Monitoring Than by Insulin Delivery Method: 3 Years of Follow‐Up from The COMISAIR Study. Diabetes Care. 2020;43:37-43.
11 Beck RW, et al. Effect of continuous glucose monitoring on glycemic control in adults with type 1 diabetes using insulin injections: The DIAMOND randomized clinical trial. JAMA. 2017;317(4):371-378.
12 Aleppo G, et al. The Effect of Discontinuing Continuous Glucose Monitoring in Adults With Type 2 Diabetes Treated With Basal Insulin. Diabetes Care. 2021;44(12):2729-2737.
13 Visser MM, et al. Effect of switching from intermittently scanned to real-time continuous glucose monitoring in adults with type 1 diabetes: 24-month results from the randomised ALERTT1 trial. Lancet Diabetes Endocrinol. 2023;11:96–108
14 Lind M, et al. Sustained Intensive Treatment and Long-term Effects on HbA1c Reduction (SILVER Study) by CGM in People With Type 1 Diabetes Treated With MDI. Diabetes Care. 2021;44(1):141-149.
15 Diabetes Control and Complications Trial (DCCT). Diabetes Care. 1987;10(1):1-19. Doi: 10.2337/diacare.10.1.1