The retina is the layer at the back of the eye which is made up of light-sensitive cells, like the film in a camera.

These cells turn the light into signals which are sent to the brain, which converts the information into your view of the world. The retina is thin and delicate and has no pain receptors. Retinal problems tend to have symptoms of:

• Flashing lights, due to pulling on the retina
• Floaters, an increase in the number of worm-like cobwebs (visible against a white wall or blue sky), sometimes a significant increase
• A curtain or veil across your vision
• Distorted or twisted straight lines

If you experience any of these symptoms, especially if they appear suddenly or increase a lot, then you should seek immediate help from your nearest Eye Casualty Unit.

A naevus is a birthmark at the back of the eye.

These are normally harmless, but they do need monitoring regularly with an OCT scan (optical coherence tomography) which provides a 3D scan of the naevus and allows us to see even the smallest of changes.

The vitreous is the gel that fills the eye, and it attaches to the retina at the back of the eye.

As we age the vitreous shrinks, and it can break away from the retina. Very occasionally, as the vitreous breaks away from the retina, it can cause a small tear.

If you experience flashing lights and floaters, it is important to check your retina carefully to see if there is any risk of tears.

If the retina moves (detaches) from its normal position it rapidly stops working because it no longer receives the normal blood supply.

Retinal detachments can develop from retinal tears or other problems such as diabetic eye disease, eye injuries or elevated levels of short-sightedness.

If a retinal detachment is detected and treated very quickly with surgery, further sight loss can be prevented.

Macular degeneration comes in two types: wet and dry.

Dry AMD is the most common and is part of the natural aging process whereby ‘drusen’ deposits build up in the macula area at the back of the eye, the part of the retina which gives us our detailed high-resolution central vision.

There are no treatments for dry AMD but a diet rich in anti-oxidants and minimising exposure to UV light can help to slow down its progression.

Magnifying aids can help in more advanced cases. It is important to regularly monitor dry AMD to make sure it does not become wet AMD.

Wet AMD is where the blood rich layer beneath the retina leaks and lifts the retina causing quite a sudden reduction in vision.

This can be treated with injections to help clear the leaking blood, but early treatment is important to have the best outcome and to reduce the subsequent scaring on the retina.

Diabetic retinopathy is an eye condition caused by diabetes, where abnormal blood vessels grow in the retina. People with type 1 and type 2 diabetes can both suffer from diabetic retinopathy.

Risk factors include those who have had diabetes for a long time and those where blood sugar levels are not under control. Whilst initially it may cause very few problems to vision, when left it can lead to blindness.

To minimise the risk of developing diabetic retinopathy, patients should maintain their blood sugar levels, blood pressure and cholesterol.

Everyone with diabetes over the age of 12 can attend an annual eye screening test. If you have diabetes and haven’t attended the diabetic eye screening service within the last 12 months, it is important to arrange a screening soon. Your GP can arrange this for you.