Causes of Diabetic Retinopathy
Poor diabetic control, which results in consistently high blood sugar levels over long periods, is the main cause of diabetic eye disease.
Diabetic eye disease, also known as diabetic retinopathy, affects up to eight out of ten patients who have had diabetes for 10 years or more.
Types of Diabetic Retinopathy
There are two types of sight-threatening diabetic retinopathy:
Diabetic Macular Oedema (DMO)
Fluid leaks out of tiny, damaged blood vessels in the back of the eye and accumulates in the macula, the central part of the retina responsible for fine details and central vision.
This leads to swelling of the tissue and blurred vision. Over time, patients with diabetic macular oedema can develop poor central vision, making reading or driving difficult, although peripheral vision usually remains normal.
Proliferative Diabetic Retinopathy (PDR)
PDR is the advanced stage of diabetic eye disease. Abnormal, fragile blood vessels grow on the surface of the retina, which can lead to permanent vision loss due to bleeding, retinal scarring, and retinal detachment.
How Diabetic Macular Oedema Causes Vision Loss
Vision loss occurs when fluid builds up in the macula (the centre of the retina that provides sharp vision), causing swelling. Early on, changes may not be noticeable. Over time, diabetic macular oedema can blur central vision. A healthy macula is essential for clear vision.
Who Is at Risk of Diabetic Macular Oedema
All people with type 1 and type 2 diabetes are at risk.
You are at greater risk if you:
- Have had diabetes for a long time (about one in three people with diabetes for 20+ years will develop DMO)
- Have poorly controlled blood sugar
- Have high blood pressure
- Have high cholesterol
- Smoke
- Are pregnant
How to Reduce the Risks
Diabetic macular oedema may be detected during annual eye screening visits offered to all patients with diabetes. Digital photographs of the retina can reveal early signs, often before any vision changes are noticed.
If detected, treatment should begin as soon as possible to prevent vision deterioration.
Treatment for Diabetic Retinopathy
Regular Eye Checks
Regular eye checks are essential for all diabetics to detect signs of diabetic retinopathy as early as possible. If you experience blurred vision, you should visit an eye specialist immediately.
Laser Treatment
Laser photocoagulation is used to treat areas of leakage in the retina. This slows fluid accumulation and may prevent further vision loss. While laser treatment may not always restore vision, it can stop it from worsening.
Eye Injections
In some cases, anti-VEGF injections (e.g., ranibizumab/Lucentis and aflibercept/Eylea) are administered directly into the eye. These medications prevent the formation of new blood vessels and can improve or stabilise vision.
Eye Surgery
Vitreoretinal surgery may be needed if:
- A large amount of blood has collected in the eye
- Extensive scar tissue is likely to cause, or has already caused, retinal detachment
Surgery involves removing the jelly-like substance (vitreous) behind the lens to restore clarity and prevent further damage.