Dr Paula Diab advocates the need to move away from a curative, rehabilitative model of treating diabetes and invest time and money into preventing the complications, such as eye disease, by early detection, timeous treatment where necessary and appropriate follow-up.
It’s probably fairly common knowledge that diabetes can affect your eyes and, in some cases, even cause people to lose their sight completely. It’s estimated that over 7 million people over the age of 40 have some degree of diabetic retinopathy and that this number will increase to 11 million by 2030. The good news though is that it’s estimated that 95% of severe visual loss from diabetic retinopathy can be prevented.
Who is at risk?
All people with diabetes, be it Type 1 or Type 2 diabetes, are at risk. Complications are more common in those people who have had diabetes for longer or whose diabetes has been uncontrolled, but that doesn’t mean that everyone else is safe.
Anyone who already has another form of vascular disease is already at high-risk of developing eye disease. The blood vessels in the eyes are obviously much smaller than those in the heart, brain and limbs so we can often pick up early vascular disease much earlier by shining a light in the eye than we can on an angiogram. Anyone who already has heart disease, suffered from a stroke or heart attack or poor limb perfusion is most certainly already at high-risk.
Because the eyes also have multiple vessels that supply them, the clinical signs of poor vision don’t always correlate with the pathological decline. In other words, it’s not reliable to wait until you experience visual loss or a deterioration in your vision before getting your eyes examined.
How is it detected?
The only way of detecting diabetic eye disease is by regular screening by an optometrist or ophthalmologist. This is not the same as your annual update of your glasses or contact lenses. This is a comprehensive examination where the optometrist or ophthalmologist is specifically looking for complications related to diabetes.
When we renew our script for glasses or contact lenses, we are concentrating mainly on the lenses, the windows of the eye through which we see. In diabetes, we need to assess the blood supply and the potential damage to the retina of the eye which often requires a more sophisticated examination and photographs to be taken. Current South African guidelines recommend that every person with diabetes has their eyes screened at least annually from the time of diagnosis of diabetes, even in childhood.
As mentioned above, please don’t wait for deterioration in your vision before you seek help; at this stage it’s often too late. Regular monitoring and documentation of declining eye function often encourages a diabetologist to enhance medical therapy and prevent the decline in vision before it becomes noticeable. This is why comprehensive care and good communication amongst the various specialists is vital.
How can eye disease be treated?
Firstly, and most importantly, addressing any additional risk factors is very important.
- Stop smoking.
- Ensure that your blood glucose levels, blood pressure and cholesterol levels are well within target and that you’re taking all the correct medication.
- Maintaining a healthy diet and regular physical exercise will also go a long way to ensuring good cardiovascular health.
Some eye conditions can be treated with eye drops and topical medications whilst others may need surgical intervention. Eye surgery and treatment has progressed at a rapid rate over the last few years and many procedures are extremely safe, quick and have remarkable outcomes. However, the longer that these diseases are left before treatment is commenced, the more difficult it becomes and the more the prognosis deteriorates.
What type of damage can occur?
Diabetic retinopathy is a general term for all disorders that affect the retina caused by diabetes. The retina is the back surface of the eye where all the blood vessels are found and where the images we see are imprinted onto the retinal cells. It stands to reason that if these blood vessels are blocked or leaking in any way, that the images we see may not be correct.
Proliferative retinopathy refers to the new vessels that are formed when older vessels become damaged or obstructed. These new vessels are often fragile or weak and can leak into the vitreous humour (jelly-like substance at the back of the eyeball) causing haemorrhages, scar tissue and even retinal detachment.
Non-proliferative retinopathy refers to the phenomenon where capillaries in the back of the eye balloon and form pouches. As the condition worsens, more blood vessels become blocked depriving areas of the retina from their blood supply. This results in new but weaker vessel formation.
Maculopathy is when fluid leaks into the centre of the macula, causing the macula to swell and blur the vision. The macula is the central area of the retina where colour vision is perceived and where the image is the most focussed.
Cataracts may also be found as a result of diabetes although they may also occur independently of blood glucose levels. These cause cloudy vision and difficulty with night vision.
Glaucoma (damage to the optic nerve) caused by an increased pressure build-up within the eye can also be a consequence of diabetes and may occur quickly or over a longer period of time but can also have a severe impact on vision.
What should you do?
Talk to your doctor today and ask for a referral to get your eyes tested as soon as possible. South African guidelines recommend that you get your eyes checked annually regardless of what visual symptoms you may have.
Trials have shown that good glycaemic control, managing other risk factors and regular eye screening can prevent or delay many complications related to diabetic eye disease. Test your glucose levels regularly and understand the fluctuations that occur on a daily basis. Ask your doctor to explain how you can manage your diabetes more effectively and look for complications. Don’t wait for the symptoms before you act.
Finally, please don’t put off these tests because you can see okay or just got new glasses last month. Diabetic eye disease is preventable and treatable if detected early. It’s also an excellent sign of other vascular damage in the body and a skilled clinician will be able to adjust your chronic medication to address these changes and prevent any further damage taking place. There is no need to lose your vision due to diabetes.
MEET THE EXPERT
Dr Paula Diab is a diabetologist at Atrium Lifestyle Centre and is an extra-ordinary lecturer, Dept of Family Medicine, University of Pretoria.
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