- Diabetic retinopathy is the leading cause of blindness in people of working age in industrialised countries. It is estimated that 12% of people who are registered blind or partially sighted in the UK have diabetic eye disease.
- 50% of people with Type 1 diabetes and 30% of those with Type 2 diabetes will develop some form of retinopathy in their lifetime and need treatment to reduce the risk of vision loss.
- If diagnosed early enough diabetic retinopathy is a treatable condition.
- The best way to try to prevent the development of retinopathy is to aim for tight control of blood glucose levels [as near normal HbA1cs as possible] and good control of blood pressure [lower than 130/80mm Hg]. These targets are not always achievable in everyone.
- The only treatment for diabetic retinopathy is laser treatment. It can stop the progression of retinopathy and help to maintain sight.
- Everyone with diabetes is entitled to free eye screening for retinopathy. In 2003, the Government set national targets for eye screening – everyone with diabetes was supposed to be screened by 2008. In 2009 Department of Health figures show that around 700,000 people with diabetes in England are still not being screened.
- There are two vulnerable groups of people susceptible to retinopathy – firstly, pregnant women and secondly, children and adolescents. In the long term children and adolescents are at greater risk of microvascular and macrovascular complications of diabetes.
What is diabetic retinopathy?
Retinopathy is usually classified according to its severity. This may not be the same in both eyes. There are two classifications of diabetic retinopathy:
This is the first stage of the development of retinopathy and it is rare before 8 to 10 years of diabetes duration. At this stage the vision is normal and sight is not threatened. If there are diabetic changes present such as small haemorrhages, fatty deposits [exudates] or abnormal blood vessels [microaneurysms] then this is a sign that the retinopathy is worsening and the doctor will be alerted to arrange more frequent follow ups.
This is where the blood vessels [capillaries] block and starve the retina of nutrients causing new vessels to grow. These new vessels grow either in front of the retina on to the back of the vitreous or occasionally on to the iris. The new vessels are fragile and may bleed into the vitreous which then affects the sight and may cause floaters, dots or lines and if severe, may cause clouding of the vision or loss of vision.
If the vessels grow on the iris, they can cause a rise in pressure in the eye and severe, painful glaucoma. The new vessels eventually cause scar tissue and this can lead to a retinal detachment where the retina becomes detached from the back of the eye resulting in severe loss of sight.
Points to remember:
- If diagnosed early enough diabetic retinopathy is a treatable condition.
- Regular eye checks do not prevent retinopathy but do enable early diagnosis and early treatment which will benefit your sight.
- Small blood vessels in the retina become blocked, swollen or leaky causing oedema and new, fragile vessels grow haphazardly in the retina. This process can continue for years without causing visual symptoms or visual impairment: during this period, retinopathy can only be detected by eye examination.
- For people with diabetes, eye checks are free in the UK.
- In insulin treated diabetes, annual eye checks should be carried out and in children and young people after the onset of puberty.
- In people with diabetes not using insulin, then eye checks should take place annually from diagnosis onwards.
Who may be at risk of developing diabetic retinopathy?
Retinopathy can affect people with all types of diabetes:
- Anyone with diabetes treated with insulin, both young and old.
- People with Type 2 diabetes treated with diet and tablets or diet only.
- People who have well-controlled diabetes can develop retinopathy.
Can retinopathy be prevented?
No, but early ‘good’ blood glucose control and blood pressure may slow down the rate of progression of the condition. Improving diabetic control rarely has an effect on diabetic retinopathy itself, but it can prevent further deterioration. Therefore you should:
- Always take your diabetic treatment – not doing so is harmful.
- Control your diet.
- Avoid becoming overweight.
- Avoid smoking and alcohol.
- Have regular blood pressure checks.
Retinopathy and genetically produced synthetic ‘human’ insulins
Two of the major insulin manufacturers have admitted that ‘human’ insulin therapy may cause serious adverse reactions. These are very much in line with the evidence from a significant number of patients.
On April 24th 2000, insulin manufacturer, Aventis Pharmaceuticals, issued the following statement in a press release:
“Human insulin therapy may be associated with hypoglycaemia, worsening of diabetic retinopathy, lipodystrophy, skin reactions (such as injection-site reaction, pruritus, and rash), allergic reactions, sodium retention and oedema.”
In the Patient Information Leaflets for some of the insulin analogues, oedema in the eye has also been listed as a possible adverse effect.
The use of synthetic may be putting some people at risk of unnecessary and avoidable complications to which they are already susceptible. Any increased risk of blindness or visual impairment is unacceptable to patients when there are natural insulins available in the UK that have not been said to cause such risks.
Retinopathy and driving
You should tell the DVLA and your motor insurers, if you have retinopathy that requires treatment or has been treated as this can affect your vision or visual fields. It is a condition that should be declared under the item ‘has there been any material change that could affect your driving.’ If you were involved in an accident and you had not declared that you have retinopathy, then you may not be insured and the DVLA could take action because you have not informed them.
Pycnogenol – are we missing something?
What is it and what does it do?
Pycnogenol is the extract of bark of a particular pine tree only known to grow in a specific area in France. Apparently French people with diabetes and retinopathy are often treated with a patented pill called Pycnogenol – not known to be used in the UK or the US.
Pycnogenol apparently is made up of a particular group of bioflanonoids that have been shown to improve the elasticity of the very small blood vessels [capillaries]. It has also been shown to have antioxidant powers that get rid of the free radicals – these are harmful molecules that lead to vascular and other problems.
An article in Diabetes Interview [March 1999] reports a man who was diagnosed with retinopathy requiring laser treatment in 1982. He searched for a possible solution himself and found Pycnogenol in France – his retinopathy regressed and he has had no laser treatment.
We have to be aware that this could happen naturally but…
- A study published in Ophthalmic Research in 1996 proved Pycnogenol’s beneficial effects on the retinas of pigs and cows.
- In the Journal of Cardiovascular Pharmacology, October 1998, it was shown to counteract the blood vessel restricting effects of adrenalin, to decrease the clogging of blood vessels by decreasing platelet clustering and adhesion.
- In the journal Free Radical Biology and Medicine, May 1998, it was shown to significantly decease nitrogen monoxide generation [this is important in many diseases including diabetes].
- In Biotechnology Therapeutics, 1994-95, it was shown to protect the cells lining the lymphatic vessels and the heart from injury due to oxidation.
- In Phytotherapy Research [15;219-233:2001] 30 people with diabetes were treated with 50-mg doses of Pycnogenol 3 times a day for 2 months and 10 people in a control group were treated with a placebo [dummy pill]. The researchers found that in those who took Pycnogenol there was a slowing down of the progression of retinopathy and in some cases the progression actually halted but in the control group using the placebo, retinopathy only got worse. This study should be treated with some caution because it was only small.
Despite efforts to achieve near normal blood glucose levels, in industrialised countries diabetic retinopathy is still the leading cause of blindness in the working population. This emphasises the need to investigate all possible avenues to prevent people from becoming blind or visually impaired. Therefore IDDT welcomes the findings of this last study and believes that it should not be dismissed simply because Pycnogenol is a herbal remedy. There needs to be further independent studies using Pycnogenol involving greater numbers of participants over a greater duration of time.
To those that either have or are at risk of retinopathy, every avenue of possible prevention or stabilisation should be considered and explored. We now have laser treatment but this does not mean that we should be complacent and not look for other means of prevention and treatment. It surely must be worth some research funding or a review of published studies.
The use of Pycnogenol must not be a seen as a substitute for ‘good’ control and because of its powerful antioxidant effects should only be used in consultation with your medical adviser, as indeed should all supplements and complementary medicines. It is also essential that the use of Pycnogenol does not replace essential regular eye examinations.
More information is available on the manufacturer’s website www.pycnogenol.com