Diabetes has rapidly gained the status of an epidemic in India, with more than 62 million people diagnosed with diabetes. India is now being regarded as the diabetes capital of the world with more than 5% of its population suffering from diabetes. While it is common knowledge that there are two forms of diabetes type 1 and type 2 with the later being common, it is important to realise that both types of diabetes are associated with numerous complications that can affect all organs of the human body.
Patients with diabetes should have regular screening of the eyes because of the myriad of problems that range from blurring of vision to blindness. This has in fact been highlighted in the VISION 2020 a global initiative that aims to eliminate the main causes of avoidable and treatable blindness. Both type 1 and type 2 diabetes can cause eye problems depending on the duration of diabetes and how well the blood sugars have been controlled. We discuss below the various manifestations of diabetes on the eye.
Blurred vision: - The lens in the eye helps us focus on objects, this is very similar to what happens in a camera.In people with very high blood sugar the lens could swell and can affect the ability to see.
Treatment - To correct this one needs to get the blood sugars back in to the target range (70-130 milligrams per decilitre, or mg/dL, before meals, and less than 180 mg/dL 1 to 2 hours after a meal). It might be three months before the vision returns to normal.
Blurring of vision is also a common symptom that might help patients with diabetes recognise an episode of hypoglycaemia (rapid decline in blood sugars to less than 50mg/dl). Again restoring the blood sugars back to the target range will normalise the vision.
Cataracts: - Patients with poorly controlled diabetes can develop clouding of the lens in the eye. The elevated blood sugars and their breakdown products accumulate eventually leading to swelling and subsequent rupture of the lens fibres, this initiates the process of cataract formation. Common symptoms include blurring and glare during the early stages and in the later stage inability to see.
Treatment – A surgery is necessary toremove the cloudy lens and replace it with an artificial one.
Diabetic Retinopathy: - The back of the eye is lined by a sheet of cells (retina) that translates the light it receives and sends it via the optic nerve to the brain where the image is interpreted. Very tiny blood vessels serve to maintain the nutrition of the retina. In patients with poorly controlled diabetes these tiny blood vessels can get blocked or damaged due to high blood sugars, if this is not identified and treated earlier can lead to irreversible blindness.
Your doctor is able to identify this during the annual check up by different tests and photographs of the back of the eye. Children diagnosed with type 1 diabetes, retinopathy may develop before their puberty if their blood sugars are poorly controlled. In patients who are diagnosed with diabetes later in life may have signs of eye problems at diagnosis or may develop problems in 10 to 15 years.
There are various stages of retinopathy,
Background diabetic retinopathy is an early stage where the damage has occurred, but there are no problems with the vision. Left untreated with poor sugar control this can further worsen.
Maculopathy is the swelling of the most critical area of the retina and can result in significant damage to the vision.
Proliferative Retinopathy, when there is not enough blood supply to the back of your eye due to the lack of oxygen new vessels can develop. Since the new vessels are very frail they can bleed and clot and this can in turn cause scars and adhesions leading to retinal detachment.
Treatment – Tight control of blood sugars requiring treatment with multiple daily insulin injection or delivery of insulin via an insulin pump will help stop any further deterioration. However if there are areas where there has been leak of blood or new blood vessels are seen laser treatment to burn away the new vessels and surgery may be the only available options that could prevent blindness.
Glaucoma: - Increase in the pressure of the fluid inside the eye is referred to as glaucoma.
The risk of developing glaucoma in patients with diabetes is nearly doubled in comparison to normal people. Some of the common symptoms include headache, pain behind the eyes, watering, halos around lights, holes in the vision and vision loss.
Pressure builds up in the eye due to increased production of fluid (open angle glaucoma) or when the fluid can’t drain like it should (Angle closure glaucoma).
Open angle glaucoma may not cause any symptoms until further along when it may present with significant visual loss. This can be picked up by your doctor during the routine annual check up. It is possible to treat open angle glaucoma with medications that can slow the amount of fluid made in the eye or speed up the drainage of the fluid.
Patients with poorly controlled diabetes develop proliferative retinopathy, this is associated with leakage of blood and growth of new vessels on the iris (the coloured part of your eye) causing an increase in the pressure within the eye due to blockage to the flow of fluid. This type of glaucoma is referred to as the neo-vascular glaucoma. This mayrequire LASER surgery or implants to help drain the fluid.
Recommendations: -A full eye check up on a yearly basis is necessary for all diabetic patients to identify these problems early and enable appropriate treatment.
If diabetic women are planning to get pregnant it is important that their blood sugar control is optimal and should have a full examination of their eyes before they conceive. Pregnant diabetic women are at higher risk for development of eye related complications and further deterioration of previously existing eye problems during the course of pregnancy and should therefore have their eyes checked every 3 months.
QUOTE: NEVER UNDERESTIMATE THE POWER OF AN ANNUAL EYE CHECK UP. IT COULD GO A LONG WAY IN PROTECTING YOUR EYES.
Dr. Santosh Shankarnarayan
MBBS, MRCP, FRCP (UK) CCST Diabetes & Endocrinology
Apollo Sugar Clinics