Diabetic Retinopathy:
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Eye Problems:

It may seem obvious, but looking after your Eyes is vital if you want to keep good vision, or at least delay the deterioration of any existing eye problems that you already have; most diabetics see quite well and have no major eye problems, but others develop Retinopathy, a disease of the Retina of the eye and the most common form of blindness in the UK; so if you are a diabetic it is essential that you have your eyes Screened for Retinopathy as least once a year.

What Is Retinopathy?

Retinopathy is the name given to a disease of the Retina caused by diabetes and it is a diabetic complication that affects the blood vessels that supply the Retina; there are 4 main types of Retinal damage that can occur if you are a diabetic, No Retinopathy, Background Retinopathy, Maculopathy and Proliferative Retinopathy; unfortunately, the condition can progress from No or Mild Retinopathy to a much more severe type of Retinopathy; however, blindness and partial blindness from Retinopathy can in theory be prevented by regular Eye checks and by diabetics controlling their diabetes.

What Is The Retina?

The Retina is a light sensitive layer of delicate tissue at the back of the Eye that is sensitive to light and covers about 65% of its interior surface; it is also covered in tiny blood vessels, which supply the much reeded oxygen and nutrients; it is these small blood vessels that are affected by Retinopathy causing therm to become blocked and leaky; the area at the centre of the Retina is known as the Macula and this is where the fine vision is formed, allowing you to see finer detail for reading and such.

The choroid, also known as the choroidea or choroid coat, is the vascular layer of the eye, which contains connective tissue and lies between the retina and the sclera the white of the eye, which is the opaque, fibrous, protective, outer layer of the eye containing collagen and elastic fiber; the choroid is thickest at the far extreme rear of the eye, at around 0.2 mm, while in the outlying areas it narrows to 0.1 mm; the choroid provides oxygen and nourishment to the outer layers of the retina.

A (0.5 to 0.1) mm layer of around 125 million photosensitive cells, called Rods and Cones, non uniformly cover the inner surface of the Choroid and convert the incident light energy into signals that are carried to the brain by the optic nerve.

The grouping of around (119) million rods, each about 0.002 mm in diameter, act like a high speed, black and white film, but it is extremely sensitive, performing in light too dim for the cones to respond to, yet it is unable to distinquish colour and the images it relays are not well defined.

In contrast, the grouping of around (6 or 7) million cones, each about 0.006 mm in diameter, act like separate, but overlapping, low speed colour film; it performs in bright light, giving detailed coloured views, but is fairly insensitive at low light levels.

Each Retinal vessel is lined by endothelial cells, which form the wall of the cell and the endothelial cells rest on a foundation layer of basement membrane; in diabetic Retinopathy, high sugar and blood pressure levels cause the blood flow to increase, which thickens the basement membrane layer causing the layer to stop the flow of essential chemicals into and out of the Retina.

The damaged cell then releases special chemicals, growth factors such as VEGF and FGFb, that make fresh new blood vessels grow and also make the blood vessel leak more fluid; it is these new blood vessels and leaky areas that can be seen when looking into your eye and those that reduce the vision; eventually the damage is so great that the vessel closes up and the Retina stops working.

No Retinopathy:

This is where there is no indication of Retinopathy at all; many diabetics do have good eyesight and basically healthy Retinas and if they can control their blood sugar and blood pressure levels it will help to prevent, or at least slow down, any harmful changes in the future and you may even feel better for it.
 
Background Retinopathy (Early Changes):

This is the term given to the earliest stage of Retinopathy and is common with those who have had diabetes for a long time; at this stage an eye examination will reveal tiny abnormalities, the early damage of the Retina, and this is something like what an eye specialist will see when looking into an Eye; the small red dots are microaneurysms, tiny damaged capillaries, which indicate the likelihood of more severe problems in the future.

The bigger red blobs are small haemorrhages, little flecks of blood and the white dots are exudates, leakage; the sight is not affected at this stage; however, once Background Retinopathy has developed, it will deteriorate and treatment will eventually be needed; even with laser treatment the sight may be permanently affected.

The capillaries in the Retina become blocked, they may bulge slightly (microaneurysm) and may leak blood (haemorrhages) or fluid (exudates); this type of Retinopathy will not affect your eyesight, but it needs to be carefully monitored by your GP, diabetologist or eye specialist; your annual screening test will keep a close check on these early changes and make sure that any signs that there could be a progression to more serious stages of Retinopathy are detected early and treated appropriately.
Proliferative Retinopathy when the new vessels grow:

As Background Retinopathy develops, 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 new blood vessels are very delicate and bleed easily, Laser Surgery is very effective in stopping these new vessels from growing; the bleeding (Haemorrhage) causes scar tissue that starts to shrink and pull on the Retina leading to it becoming detached and causing blindness.

The Pre-Proliferative and Non-Proliferative stages are before the Retina are deprived of a proper blood supply and any new blood vessels start to grow; only between (5 and 10)% of diabetics develop Proliferative Retinopathy; it is more common in people with Type 1 diabetes.

60% of Type 1 Diabetics show some signs of Proliferative disease after having diabetes for 30 years; those that have Early or Moderate Proliferative Retinopathy should be referred for laser treatment; if you have been diabetic for ten years or more, especially if you have type 2 diabetes, you may have a combination of Maculopathy and Proliferative disease.

What is the Macular?

The Macular is the most used area of the Retina and is the part of the Retina that is responsible for our clear, detailed and sharp central vision, due to its high density of cone photoreceptors, it is situated at the back of the retina, the posterior pole, lying about 3mm lateral to the optic disc; it has a central depression known as the fovea centralis; there are nothing but tightly packed cone photoreceptors in the fovea with no overlying blood vessels and this is where visual acuity is ultimately determined.

What is Diabetic Macular Oedema (DMO)?

DMO, also known as 'Maculopathy' and 'Non Proliferative Retinopathy', is a common diabetes related Eye complication associated with Diabetic Retinopathy, where if the Retinopathy is at or around the Macula, the fluid leaking from the enlarged blood vessels builds up and causes swelling, known as 'Macular Oedema'; DMO can occur at any stage of Diabetic Retinopathy and can lead to a blurring in the middle, or just to the side of, your field of central vision, as if you were looking through a layer of fluid not quite as clear as water; DMO can cause some loss of vision, particularly for reading and seeing fine details and can even lead to a possible loss of sight.


Maculopathy is more common in people with Type 2 Diabetes and if left untreated can cause blindness; those who develop advanced maculopathy or haemorrhages may need to consider registering as blind or partially sighted; your Eye specialist and other professionals such as a social worker will be able to help.

Lifestyle:

Looking after your diabetes can prevent or at least delay further problems, which means as a diabetic you need as far as possible to keep to a healthy diet, have regular exercise and keep your blood sugar and blood pressure levels in check; diet wise you need to eat a balanced diet of fruit and vegetables, with oily fish such as sardine, salmon, tuna and trout, avoid low animal fats, keep the salt down and eat some fibre; keep your alcohol consumption down to say 1 or 2 units a day (the lower the better) and most of all you should never smoke.

You also need to do at least 30 minutes exercise a day, have regular Eye checks, at least once a year with dilated pupils, attend the Diabetic Eye Screening every year, so that a record of any changes in your eyes can be recorded, have regular HbA1C & Blood Pressure tests and attend your annual diabetic review where your urine, protein, feet and other checks should be carried out.

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