The past two decades have seen an explosive increase in the incidence of diabetes mellitus worldwide, making it one of the most common non-communicable diseases today. According to the World Health Organization (WHO), there were an estimated 135 million diabetics in the world in 2000, and this number is expected to increase to 300 million by 2025.
What is of more consequence is that India has the largest number of diabetics in the world. In 1994, 19.4 million suffered from diabetes mellitus, 32 million were diabetics by 2000 and the number is expected to increase to 57.2 million by 2025. Moreover, according to current estimates, diabetics will increase by 42 per cent in developed nations and by 170 per cent in developing nations. According to an ICMR study, prevalence of diabetes mellitus, which was 2.3 per cent in urban population in 1970, increased to 12.1 per cent in 2001.
The increase in incidence of diabetes mellitus and its complications has been attributed to change in life style caused by increased urbanization, high calorie diet, decrease physical activity and stress. Other important factors are genetic factors, family history and increased longevity. And what is worrying that diabetes is striking at an early age among the urban population.
Types of Diabetes:
Diabetes mellitus occurs in two forms:
Type 1 (Insulin dependent) – Also called juvenile diabetes, this is seen in younger people and is characterized by absolute insulin deficiency due to which these patients are completely dependent on insulin treatment. The incidence of this form of diabetes is doubling every decade.
Type 2 (Non-Insulin dependent) – This is seen in older people and is characterized by insulin resistance or abnormal insulin secretion. These patients can be treated with tablets or may require insulin. This form accounts for 90 per cent of all cases seen globally, but its increasing incidence in India is due to changing diet, from traditional Indian food to modern diet caused by a more stressful life-style and increased urbanization. This type is being seen in younger people due to obesity. Moreover, type 2 diabetics have a greater tendency to develop hypertension and heart disease.
It’s not just the disease itself that is a cause for concern. Diabetics are more prone to develop systemic complications. They are also 25 times more likely to develop blindness, twice as likely to have a stroke, 2-4 times more likely to have myocardial infarction and much more likely to develop kidney disease or undergo amputation.
Effect of diabetes on the eye:
Diabetes can cause eye complications such as:
1. Diabetic Retinopathy: This is the most common complication and it has been seen that 25 per cent of all diabetics develop this complication after 10 years of diabetes and 50 per cent develop it after 20 years of diabetes. Diabetic Retinopathy is also more common in the upper socio-economic group.
Diabetic Retinopathy has two types –
Non-Proliferative Diabetic Retinopathy – This is the early stage in which tiny blood vessels in the retina get damaged and leak blood or fluid, which cause the retina to swell or form deposits called exudates. 90 per cent of Diabetic Retinopathy cases are of this type. This stage often has no symptoms.
Proliferative Diabetic Retinopathy – This is the advanced stage. Abnormal new blood vessels grow on the surface of the retina and often bleed into the jelly in front of the retina, giving rise to floaters, dots or lines or sometimes loss of vision. These new vessels can eventually pull the retina causing a traction retinal detachment. 10 per cent of Diabetic Retinopathy is of this type.
Maculopathy – Leaking fluid collects in the centre of the retina called the Macula giving rise to blurring of vision.
Studies have shown that there has been a 3-fold increase in the incidence of Diabetic Retinopathy in India in the last 10 years.
2. Cataract – This is more commonly seen in diabetics at a younger age and more commonly in the lower socio-economic group. Important causes are exposure to ultraviolet light and oxidative stress.
3. Glaucoma – This involves increase in intra-ocular pressure within eye and is more commonly seen in persons afflicted with diabetics.
4. Diabetics are also more prone to develop paralysis of the nerves of the eyes due to obstruction of the blood supply.
Incidence of vision loss:
The following categories of individuals are at a higher risk of losing vision in diabetes:
- Those who have had diabetes from a younger age
- Those who have had diabetes for many years
- Those who have poorly controlled blood sugar
- Those who have poorly controlled blood pressure
- Those who smoke
Diet plays an important role in the control of diabetes and diabetic retinopathy. Studies have shown a much lower incidence of diabetic retinopathy in persons who follow a healthy diet. A good diet consists of
- Ghee as the cooking medium
- Fish and fish-oil capsules, which are rich in selenium and zinc. Fish is considered to be one of the best foods for diabetics
- Green leafy vegetables
- Vitamin A rich foods like carrot and green leafy vegetables
· Vitamin C rich foods such as citrus fruit like orange, lemon
- Vitamin E rich foods like cereals and grains
Diabetics must avoid fried food, animal food (except milk and fish), processed food and preserved food.
Regular eye examination
All diabetics must have the eyes examined regularly with dilated pupils. Juvenile diabetics must have their eyes examined at least once a year after the age of 12 years because diabetic retinopathy is rarely known to occur before puberty. Those with diabetes at an older age must have the eye examination done once at the time of diagnosis and then at least every 6 months to one year thereafter.
If Diabetic Retinopathy has been diagnosed, they should have the eyes examined as often as recommended by their eye doctor.
A special test called fluorescein angiography may be required to identify areas that require laser treatment. If leakages or new vessels are detected, laser treatment must be promptly given. Sometimes there is leakage of blood from the retina of the eye into the jelly in front of the retina, which may cause blurring of vision. An operation called vitrectomy may be required to remove the bleeding and replace it with clear fluid.
Studies have shown that vision can be preserved in 90 per cent of diabetics if laser treatment in done in time.
Newer treatment modalities:
Anti-VEGF Injections for Diabetic Retinopathy
Injection treatments (Lucentis™, Avastine™) used commonly for macular degeneration have also proven to be effective for diabetic eye disease, in some cases better than laser treatment.
Results from a large clinical trial conducted by the Diabetic Retinopathy Clinical Research Network, or DRCR.net, demonstrated that patients receiving a combination of anti-VEGF treatments and laser treatments had greater gains in visual acuity as compared to others.
A newer injection viz. EYLEA™ (aflibercept), known in the scientific literature as VEGF Trap-Eye, is also being used as an injection into the eye to provide a therapeutic effect in patients suffering from various eye disorders including in some cases of diabetic retinopathy.
Prevention of complications:
All diabetics must adhere to the following to prevent complications:
- Avoid obesity and have regular physical exercise
- Control the blood sugar and blood pressure at all times
- Avoid self-medication. It is better to follow the advise of a physician
- Maintain a healthy diet. Insulin or pills is not a substitute for a proper diet
- Have your eyes examined at least once every 6 months to a year by an eye doctor
Being a diabetic does not mean that you cannot enjoy a happy and healthy life. Follow the above-mentioned simple rules with a positive attitude, and you will see the change in your life.
Issued in public interest by Shroff Eye Hospital, Mumbai, India
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