What causes retinopathy?
To see, light must be able to pass from the front of the eye through to the retina, being focused by the lens. The retina is the light-sensitive layer of cells at the back of the eye – the ‘seeing’ part of the eye. It converts the light into electrical signals. These signals are sent to your brain through the optic nerve and your brain interprets them to produce the images that you see.
A delicate network of blood vessels supplies the retina with blood. When those blood vessels become blocked, leaky or grow haphazardly, the retina becomes damaged and is unable to work properly. Retinopathy is damage to the retina.
Risks to your eyes
Persistent high levels of glucose can lead to damage in your eyes. To reduce the risk of eye problems, blood glucose, blood pressure and blood fats need to be kept within a target range, which should be agreed by you and your healthcare team. The aim of your diabetes treatment, with a healthy lifestyle, is to achieve these agreed targets.
Smoking also plays a major part in eye damage so, if you do smoke, stopping will be extremely helpful.
Types of retinopathy
There are different types of retinopathy: background retinopathy, maculopathy and proliferative retinopathy.
The earliest visible change to the retina is known as background retinopathy. This will not affect your eyesight, but it needs to be carefully monitored. The capillaries (small blood vessels) in the retina become blocked, they may bulge slightly (microaneurysm) and may leak blood (haemorrhages) or fluid (exudates).
Maculopathy is when the background retinopathy (see above) is at or around the macula. The macula is the most used area of the retina. It provides our central vision and is essential for clear, detailed vision. If fluid leaks from the enlarged blood vessels it can build up and causes swelling (oedema). This can lead to some loss of vision, particularly for reading and seeing fine details, and everything may appear blurred, as if you are looking through a layer of fluid not quite as clear as water.
Proliferative retinopathy occurs as background retinopathy develops and large areas of the retina are deprived of a proper blood supply because of blocked and damaged blood vessels. This stimulates the growth of new blood vessels to replace the blocked ones. These growing blood vessels are very delicate and bleed easily. The bleeding (haemorrhage) causes scar tissue that starts to shrink and pull on the retina, leading to it becoming detached and possibly causing vision loss or blindness.
Once the retinopathy has reached this stage it will be treated with laser therapy. Beams of bright laser light make tiny burns to stop the leaking and to stop the growth of new blood vessels.