Eye problems are one of the most significant complications of diabetes, and diabetic retinopathy is the most common cause of blindness in people aged 30-65.
The retina is made up from special cells called rods and cones which line the back of your eyes. Light enters your eye and passes through the lens which focuses the light on to the retina. Messages about what you see are then passed from the cells in the retina to the optic nerve, and on to the brain. There are many tiny blood vessels next to the retina which take oxygen and nutrients to the cells of the retina.
Diabetic Retinopathy and how it occurs
The term ‘retinopathy’ covers various disorders of the retina, which can affect vision. Retinopathy is usually due to damage to the tiny blood vessels next to the retina. Retinopathy is commonly caused by diabetes, but is sometimes caused by other diseases such as very high blood pressure.
Over time if the diabetes is not controlled, constant high blood sugar levels can weaken and damage the tiny blood vessels next to the retina resulting in the following complications:
- Small ‘blow-out’ swellings of blood vessels (microaneurysms).
- Small leaks of fluid from damaged blood vessels (exudates).
- Small bleeds from damaged blood vessels (haemorrhages).
- Blood vessels may just become blocked. This can cut off the blood and oxygen supply to small sections of the retina.
- New abnormal blood vessels may grow from damaged blood vessels. This is called proliferative retinopathy. These new vessels are delicate and can bleed easily.
The leaks of fluid, bleeds and blocked blood vessels may damage the cells of the retina . In some severe cases, damaged blood vessels bleed into the vitreous humour (the jelly-like centre of the eye). This can also affect vision by blocking light rays going to the retina.
How do we treat Diabetic Retinopathy?
An eye examination can detect early signs of eye disease caused by diabetes, and digital imaging (photographing the back of the eye) is an accurate way of checking and monitoring any retinal changes from one examination to the next.
Serious eye problems are less common if the diabetes is controlled in the early stages.
Most sight-threatening diabetic problems can be prevented by laser treatment if it is carried out early enough. It is important to realise, however, that laser treatment aims to save the sight you have – not to make it better. The laser, a beam of high intensity light, can be focused with extreme precision to seal the blood vessels that are leaking fluid into the retina. If new blood vessels grow, more extensive laser treatment may be needed.