Information about the disease
Most people know that diabetes is a disease of raised blood sugar in the body.
India is now the world’s capital for diabetes and it is predicted that in the near future there will be more than 100 million diabetics in India.
- It is also predicted that in the future one in every 5 diabetic will be Indian.
- Diabetes is incurable however with correct treatment it can be controlled so that it does not affect one’s life.
- Untreated and uncontrolled diabetes can cause problems in almost all parts of the body
- Many people are aware that diabetes is a risk factor for heart attack and stroke.
- Unfortunately most diabetics are unaware that diabetes causes significant problems in the eyes as well.
- Diabetes affects the retina causing diabetic retinopathy.
What is the Retina?
Retina is the most important part of the eye. If we think of the eye as a camera, the retina is like the film of the camera. It is responsible for taking the photograph or what we call vision.
Retina is very thin layer of the back of the eye, which cannot be seen without special machines and tools. If the retina is damaged, even if the rest of the eye is healthy there will be no vision.
The whole eye has been made to protect and support the retina in converting light into an electrical impulse, which the brain then translates into vision.
There is no transplant or replacement for the retina and so once the retina is damaged, its permanent and so is the resulting visual loss.
What is diabetic retinopathy?
When diabetes affects the retina it is called diabetic retinopathy.
Diabetes affects the small blood vessels in the retina either causing them to shut down (occlusion) or to leak.
In a vast majority of diabetics the retinal vessels both shut down and leak.
When the blood vessels shut down due to diabetes it causes ischemia and the retinal cells die, as they do not get nutrition or oxygen. Dead retinal cells cause loss of vision.
If the blood vessels of the retina start to leak it causes swelling of the retina and fluid accumulates in the retina.
The retina is a complex structure and if there is swelling it will rot and eventually stop working, causing visual loss.
Can diabetes blind?
Unknown to most diabetics, diabetes is one of the leading causes of blindness in the world. More than 40 lac people in the world have some visual disability due to diabetes. No matter where in the world we look, diabetes is amongst the top 5 causes of blindness.
The figures of visual disability from diabetes in India are unavailable as there is no formal system for reporting visual disability in India. However, given the large number of diabetics in the country and the even larger number of undiagnosed diabetics, we can assume that this figure will be substantial.
What is most worrying is that diabetes blinds young people. It is the commonest cause of blindness in the working age group (people aged 40 to 60 years).
This is the one of the most critical times of life for most people. They have just completed their education and are on the way to establish themselves at work and have started building their life by investing in a house, car etc. This is also the age when most people start a family and have young children and they need to provide for their care, their education and also save money for their future.
If at this critical juncture one were to loose vision it is devastating not only to the individual but also his family. Due to the loss of vision they can potentially loose their job resulting in loss of income and then inability to look after the family or themselves.
Can blindness from diabetes be prevented?
With today’s technology and advanced treatment options no one should go blind because of diabetes. The key is to diagnose diabetes in the eyes early, ideally before vision is affected and treat the disease before it can affect the vision. The most essential part for preventing blindness from diabetes is the need for early detection of diabetic changes in the eyes. This can be only be achieved by routine screening of diabetics for changes of diabetes in their eyes.
What is diabetic eye screening?
Diabetic eye screening involves examination of the eyes for any changes of diabetes in the retina.
There are 2 main screening methods:
1. A detailed examination by a Specialist Eye Doctor
- The retinal examination by a Specialist Eye Doctor requires specialized machines and tools. A family doctor cannot examine the eyes for changes of diabetes.
- A good and thorough screening of the eyes needs equipment and expertise which a family doctor or general doctor will not have.
2. A digital fundus photograph of the retina by trained technicians.
- A retinal photograph needs special cameras called fundus cameras. Trained technicians or an eye doctor is needed to capture images of the retinae so that they can be examined for changes of diabetes.
- Once the retinal photographs are taken, they are then reviewed either by trained graders or by a Specialist Eye Doctor and examined for changes of diabetes in the retina.
Impact of screening
In developed countries like U.K., USA and in many countries in Europe a well-established diabetic retinopathy screening programme exists.
As soon as someone is diagnosed with diabetes they are automatically registered into the diabetic eye screening programme.
The diabetic patient attends their local diabetes eye screening location where a fundus photograph of both eyes is taken. A Specialist sitting in a distant grading centre reviews these photographs. If any signs of diabetes are seen in the retina, the patient is sent to their local Eye Specialist.
Since the inception of these screening programmes the prevalence and incidence of blindness from diabetes has decreased significantly in these countries.
Diabetes eye screening in India
Unfortunately there is no formal diabetic screening programme in India.
Hence it is up to the individual diabetic to ensure that they see the Eye Specialist regularly to ensure that they have no diabetic eye disease.
Unfortunately most diabetics are unaware that diabetes affects the eyes and can cause blindness and therefore have never seen an Eye Specialist for diabetic eye screening.
Many general doctors treating people for their diabetes are also unaware of the risks diabetes causes to the eyes and vision and hence do not recommend routine screening to their diabetics.
Most often a diabetic is sent to an eye specialist only if the vision is affected. Once the vision is affected it is often too late to completely recover the lost vision.