Diabetes and the Eye
Diabetes Mellitus is a condition where the body is not able to process all the sugar consumed through food
and the excess sugar in the system can affect many parts of the body like eyes, kidney, nerves and heart.
Once a person is detected to have diabetes, the sugar levels are brought under control by a combination of diet, exercise and medicines. The medication may be in the form of tablets or injections or both. The aim is to keep blood sugar and associated factors like lipids, hemoglobin, thyroid and blood pressure within the normal range for long term good health.
How can diabetes affect the eye?
In the eye, diabetes affects mainly the retina which is the light sensitive layer at the back of the eye. The condition is called Diabetic retinopathy. Diabetes affecting the central retina also called macula is called Diabetic maculopathy, both may coexist and the treatment modalities are different for the 2 conditions. The other conditions which may be seen in diabetics are
- Early onset of cataract
- Retinal vein occlusion
What is Retina?
Retina is a layer within the eye, which consists of specialized cells which receive light and send it to the brain through the optic nerve. The retina also consists of a fine network of blood vessels. Macula, is the central area of the retina and the most sensitive part of the retina.
How does diabetes affect the Retina?
Diabetes causes weakening of the wall of the delicate blood vessels in the retina. These blood vessels then leak fluid and in more advanced stages blood. The leaking fluid in the macular area causes Diabetic Maculopathy or Macular Edema.
With progress of the condition, the blood vessels may stop carrying blood permanently and the cells will die because of lack of nourishment. Nature’s way of trying to repair this damage is by making new blood vessels. These new blood vessels attempt to start the blood flow but they are weak, and tend to leak blood causing more damage. The blood leaks into the cavity of the eye causing rapid loss in vision. The leaked blood then shrinks and distorts the retina causing retinal detachment.
The 2 main vision threatening conditions in diabetic retinopathy are macular edema and proliferative retinopathy which may result in bleeding within the eye. This bleeding causes severe vision loss and may later progress to cause retinal detachment.
There are no early symptoms in diabetic retinopathy. Blurring of vision indicates fairly advanced retinopathy. Routine comprehensive eye evaluation helps detect early diabetic retinopathy changes and timely treatment can preserve vision. Hence regular visits for eye checkup are critical for preventing visual loss.
Will all diabetics get diabetic Retinopathy?
Any person with diabetes can develop diabetic retinopathy. Studies have shown that 18% of diabetics can develop retinopathy. Those who do not keep blood sugar under control have a higher risk of developing retinopathy. Early age of onset of diabetes and longer duration of diabetes have a higher chance of developing retinopathy
How frequently must I have my eyes examined?
If you are a diabetic you should have your eyes examined by an ophthalmologist
- No retinopathy – annual check up
- Mild retinopathy – 6 monthly check up
- Moderate to severe retinopathy – monthly once to three monthly – the decision will be taken by your eye specialist.
What investigations are done in diabetic retinopathy?
Vision, Refraction, slit lamp examination, intraocular pressure measurement and retinal examination by indirect ophthalmoscopy (which are part of a comprehensive eye checkup), is the routine clinical examination done for a diabetic.
Optical Coherence Tomography (OCT) – a non-contact test which scans the various layers of the retina especially at the macula (central retina) and gives detailed information.
OCT Angiography(OCTA) - is a relatively new tool which is incorporated in the newer OCT machines and is able to delineate the blood vessels in various depths of the retina thereby giving more information about the extent of the pathology
Fundus Fluorescein Angiography (FFA) – a dye is injected and photos of the retina are taken. This will help detect the leaking areas and any areas which are ischemic(less blood supply)
How is Diabetic Retinopathy treated?
Laser Treatment – One or more sessions of laser treatment for retinopathy or maculopathy are given where required. The laser treatment is an outpatient procedure and is not painful. Following this treatment the patient may need to use some drops but otherwise can immediately return to normal activities. The aim of the laser treatment is to prevent further loss of vision and stabilize the condition.
Surgery – For advanced retinopathy, surgery may be needed to clear the blood or to reattach a detached retina.
Your eye specialist trained in treating retinal conditions will advise you on the type of treatment.
- Eyes can be affected in diabetics
- 7% of the newly diagnosed diabetics have diabetic retinopathy
- Checking for glass power and changing glasses alone is not sufficient
- Early eye involvement in diabetes has no symptoms
- Only a thorough eye examination by an eye doctor will detect early changes
- Early detection of diabetic retinopathy can considerably reduce the risk of visual loss in diabetic individuals
- Diabetic retinopathy is preventable and treatable – Periodic eye evaluation is the key to good ocular health and vision