DIABETIC EYE DISEASES
Ophthalmologist Dr Shanel Sharma
explains why it’s vital to be vigilant if you have diabetes and why the
eye is vulnerable to damage from the complications of diabetes.
Diabetes
is the most common cause of blindness for people between 20 and 65 and
diabetic eye diseases can affect anyone with diabetes whether type 1 or
type 2. Chronically high blood glucose levels over time damage blood
vessels throughout the body. Our small blood vessels are the most
vulnerable and are affected first. These include the small blood vessels
supplying our eyes, kidneys and our peripheral limbs (toes). People
with chronically elevated blood glucose levels have substantially more,
and more severe, retinopathy than those with lower blood glucose levels.
What
happens in the eye is that the blood vessels become damaged and develop
micro-aneurysms, start to bleed causing haemorrhages and stop carrying
blood, resulting in retinal ischaemia. Ischaemic retina causes the
release of a protein (VEGF – vascular endothelial growth factor),
resulting in the development of sick and abnormal blood vessels, which
can bleed or cause tractional retinal detachment and loss of vision. The
other major way people lose sight is from diabetic macular oedema, from
leaking of blood product into the macular. The macular is the part of
the eye that allows one to read, look at people’s faces, or do any fine
detailed work.
As there is usually a 10–15-year delay in chronically high BGLs
and appearance of diabetic eye diseases, it is important to control BGLs
well from the start. Although the damage to the eye is irreversible,
early detection and treatment can reduce the risk of blindness by up to
approximately 95%.
If you are diagnosed with diabetic
retinopathy, don’t despair. Good blood glucose control can reduce its
progression. People with diabetes who follow healthy eating principles
can reduce their HbA1c levels by 1 to 2 percentage points. On a low GI
diet, they can reduce can HbA1c levels by another 0.5 percentage points.
While this may not sound significant, a decrease of just 1 percentage
point in HbA1c levels will decrease the common complications of diabetes
by 19% to 43%. Talk to your doctor or diabetes educator.
Reducing
blood pressure helps too. The UK Prospective Diabetes Study showed a
reduction of 10mmHg systolic and 5mmHg diastolic reduces the rate of
retinopathy by 30%.
As diabetic eye diseases most
commonly have no symptoms, it is essential to ensure that you are being
screened regularly by your GP, optometrist or your ophthalmologist.
Symptoms that are associated with diabetic eye diseases can include
intermittent blurred vision, difficulty with focusing, loss of contrast,
double vision or distortion to your vision. Additionally, diabetes is
an independent risk factor for developing other eye diseases such as
cataracts and glaucoma.
Protecting your eyesight is one of the most important things you can do to ensure quality and enjoyment of life.
Read more:
- Preventing Diabetic Retinopathy Progression
- Diabetic Retinopathy and Systemic Factors
- Blood pressure control for diabetic retinopathy
- Risks of progression of retinopathy and vision loss related to tight blood pressure control in type 2 diabetes mellitus (UK Prospective Diabetes Study)
- Dietary hyperglycemia, glycemic index and metabolic retinal diseases
