What is diabetes?
Diabetes is a chronic (long-lasting) health condition that affects how your body turns the glucose from the food we eat into energy. After we eat, glucose normally passes to our bloodstream and then a hormone called insulin facilitates its uptake into our cells.
Diabetes occurs when our body is no longer able to make insulin or when it is unable to utilise insulin correctly. As a result blood glucose levels become high (hyperglycaemia).
Hyperglycaemia leads to blood vessel, tissue and organ damage and may even lead to blindness.
How does diabetes affect the eyes and vision?
Vision changes may be one of the first symptoms of diabetes. As blood glucose levels fluctuate this leads to vision instability with some days being worse than others. If your distance vision appears to suddenly worsen this may be a sign of hyperglycaemia causing pseudo myopia (false short-sight)
If you are a diabetic and are requiring an update to your glasses, it is important that your optometrist checks that your vision and prescription is stable before updating your lenses. This may entail being tested on different days to ensure the correct prescription is given.
Hyperglycaemia damages small blood vessels making them leaky. As the retina (the light sensitive lining of the back of the eye) maintains many fine vessels; diabetic eye disease or retinopathy may include micro aneurysms (small out-pouches of the blood vessels), haemorrhages (bleeding into the retina) or exudates (leakage of fats and proteins) as well as retinal oedema (swelling).
If damage occurs at the centre of the retina (the macular), loss of vision may occur.
More advanced diabetic retinopathy (DR) may result in proliferative DR (fine blood vessels grow in an attempt to nourish the compromised retina- this in turn may lead to scarring and retinal detachment.
Treatment for diabetic eye disease
· Laser treatment- seals off affected blood vessels, preventing further leak and vessel growth
· Intraocular injections-using medication to inhibit macular oedema and new blood vessel growth
Prevention- what you can do
· Monitor your HbA1c- the best measure of your blood glucose levels over the preceding few months.
· HbA1c of 43-52 reduces the chance of sight-threatening eye disease. HbA1c over 64 means sight-threatening eye disease is likely to develop.
· Manage your blood pressure and blood cholesterol levels with medication and lifestyle changes.
· Monitor your blood glucose levels at home to manage your glucose control on a daily basis.
· Have a retinal eye exam including retinal photography if newly diagnosed with Type 2 diabetes.
· Have a retinal exam within 5 years of Type 1 diagnosis or for children by the time the child is 10 years old – whichever comes first.
· Regular dilated eye exams with retinal photography every 2 years or as directed by your optometrist or ophthalmologist.
· Ask your GP to enrol you in the diabetic photo screening program offered by your local DHB.
· Visit your optometrist at any stage if you notice any vision changes.