DIABETES AND EYE HEALTH
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. BACKGROUND 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 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 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. HOW IS
RETINOPATHY TREATED? LASER TREATMENT : The type of laser treatment used to treat diabetic retinopathy is called photocoagulation. Many people having laser treatment have very little visual impairment. Others who may have early or moderate maculopathy and proliferative retinopathy will also benefit from laser treatment. Laser treatment has revolutionised retinopathy treatment. Together with effective screening, good blood glucose control and good blood pressure, it can successfully maintain vision. Tiny laser burns allow more oxygen and nutrients to reach the retina, which improves the blood circulation. This signals that there is no need for 'new vessels' to be produced. You may need more than one treatment as the vessels may start growing again.
WHAT’S THE PROCEDURE ? You have local anaesthetic and pupil-dilating eye drops put in your eye.A special contact lens is placed on your eye to hold your eyelids open and allow the laser beam to focus onto your retinaThe laser beam is directed at damaged areas of the retina.Small bursts of tiny beams of laser light then seal leaky blood vessels and destroy abnormal new blood vessels in the retina. An eye specialist (ophthalmologist) carries out laser treatment and nearly always as an outpatient procedure, allowing you to go home afterwards. A session of treatment can vary in length from person to person. Ask your eye specialist how long your sessions will last and whether you will be expected to come back for more treatment. As a local anaesthetic is used, laser treatment is not painful for most people, although a few will experience some discomfort. Many people say that the first laser sessions are not painful, but treatment can become uncomfortable if many sessions are needed. Before your laser sessions, speak to your eye specialist about using your usual methods of pain relief, should it be needed. Some lasers operate with bright flashes of light during a session. In others, the beam is invisible to the person. Whichever method is used, most people describe feeling slightly dazzled or say that their vision is affected for a while immediately after treatment. However, vision should return to normal after a few hours. It is a good idea to ask a friend or family member to come home with you after a session, and to allow yourself time to rest quietly. As your eyes will take time to return to normal after the treatment, remember to: Take sunglasses with you as your eyes may be more than usually sensitive to bright light for a whilearrange for someone to drive you home, because the dilating drops will temporarily blur your vision. Anti-VEGF (INTRA-OCULAR) INJECTION An anti-VEGF injection is for the treatment for maculopathy and can stablise and help rapidly improve vision. Vascular endothelial growth factor (VEGF) is a protein produced by the retina that stimulates the growth of new blood vessels. It is part of the system that restores the oxygen supply to tissues when blood circulation is inadequate. It is activated when blood vessels are blocked due to high blood glucose levels. In recent years new treatments, called anti-VEGFs, have been developed to bind to and inhibit VEGF. The intra-ocular treatment is injected directly into the eye and helps to reduce the leakage of fluids into the macular. VITRECTOMY : This is an operation that may be done when a haemorrhage does not clear within several weeks, or when the person has advanced proliferative retinopathy, or when the retina detaches or peels away from its underlying tissue. This surgery may restore useful vision but it is a major procedure and you need to discuss how well it may work with your eye specialist. WHAT’S THE PROCEDURE ? During this operation the vitreous, which gives shape and support to the back of the eye, is surgically removed and replaced with a clear substance. This operation is usually done under general anaesthetic, requiring a stay in hospital. The outcome depends on a number of factors. The best person to advise you on your suitability for this or any other eye treatment is your eye specialist.
Op.Dr.Ahmet UMAY
