An eye on the future

Get your eyes checked: Some eye problems are preventable.   | Photo Credit: Photo: V. V. Krishnan

Ophthalmic surgeon Dr. Mohan Rajan answers frequently asked questions on diabetic retinopathy.

As diabetes emerges as a major epidemic in India, Diabetic Retinopathy, loss of vision due to diabetes is in sharper focus. The World Sight Day 2008 (the second Thursday of October) highlights the fight against vision impairment in later life.

How do you see our problems of sight as another World Sight Day goes by?The problem of blindness is enormous in India because of the enormity of the population. India accounts of a quarter of the world’s blind population of 80 million. The alarming fact is that 75 per cent of blindness it is avoidable.

There is a growing concern about Diabetic Retinopathy in the world. Does India face the threat on a similar scale?

Diabetic Retinopathy (DR) is the major cause of irreversible blindness in old age, and all diabetics are prone to it. It is one of the most devastating complications of diabetes. A diabetic is 25 times more likely to go blind than a person in the general population.

With Diabetes emerging as a major epidemic, India is likely to emerge as the diabetic capital of the world by 2025. The diabetic population in India has crossed 30 million, and is expected to touch 75 million by 2025. This means 20 per cent of these patients will develop DR in the eye.

How common is DR?More common than we think. About two million of the 20 million blind population has DR in India, which could multiply at least four-fold by 2020. Today a third of people with diabetes don’t know that they have diabetes. Just two-thirds seek medical attention. Only a miniscule percentage go through regular eye checkups.

Who is at risk?

All diabetics risk Diabetic Retinopathy. It may worsen during pregnancy. The longer the history of diabetes, the greater the risk of diabetic retinopathy. About half the number of diabetics will develop some degree of diabetic retinopathy during their lifetime.

Are there any contributory factors to DR?Hypertension, Renal disease, Obesity, Smoking, Anaemia… all have an adverse impact on DR. Pregnancy in women can be associated with worsening of the retinopathy. High levels of serum cholesterol and/or triglycerides are significant risk factors for retinopathy.

How does diabetes affect the eye?The pathological changes in diabetes lead to lack of blood supply (ischemia) to the retina, resulting in inadequate oxygen to the retinal tissues (hypoxia). Long-standing hypoxia leads to formation of new vessels. These are fragile, and readily bleed. Excessive bleeding in the eye leads to vitreous haemorrhage, which leads to lack of vision.

In some areas, there is a swelling of the vessel wall and the fluid leaks leading to retinal oedema. If the macula, the central part of the retina is affected, there will be a severe drop in vision. DR can be corrected in stage one and stage two by laser treatment. Stage three and stage four are advanced. There is formation of scar tissue, which pulls the retina to cause retinal detachment, resulting in permanent loss of vision.

How do you manage DR? Laser photocoagulation is the mainstay in managing DR. Advanced cases with vitreous haemorrhage and tractional retinal detachment, require surgery (vitrectomy) and laser treatment. Patients with hypertension, renal disease or pregnancy should have a regular ophthalmic check up every six months. Those who have undergone Laser should have check ups every three months.

Are there any precautions to prevent DR? An annual eye check up is mandatory for all diabetics. There must be control over diabetes by regular medication, diet and exercise. Control of associated disorders such as hypertension, renal disease, and hyperlipidemic status management is a must.

How is Vision 2020 strengthening the fight against blindness?Vision 2020 is a global initiative to eliminate avoidable blindness. Launched jointly by the World Health Organization (WHO) and the International Agency for the Prevention of Blindness (IAPB), Vision 2020 envisions a world without avoidable blindness. > How can India tackle the problem?According to a recent survey in Chennai city, only 15 per cent of the urban population is aware of the link between diabetes and eyesight. If this is the level of awareness of the urban population, what will be the state of rural areas?

India is now focusing only on curative healthcare due to the enormity of its population, and has not been able to do much in the direction of preventive healthcare. We have to shift the emphasis to preventive healthcare. If we can prevent cataract, DR, or glaucoma, we can prevent loss of vision due to various problems. We can save all the resources which are now being spent on curative healthcare.

A major step would be extensive screening of diabetics for DR. Though resource-intensive, it will yield results if it covers 80 per cent of known diabetics. The screening process should be free and convenient for patients to be effective.

The keyword seems to be awareness. How does one create awareness on the scale needed in the Indian context, given the socioeconomic barriers?The need of the hour is to ensure that awareness percolates down to all members of the community. For instance, many spectacle users get their eyes checked by an optometrist who sees only the front of the eye, and changes their glasses.

The optometrist does not look at the back of the eye, where early indications of Glaucoma, DR, or problems with the retina are available. If undetected, the symptoms do not surface until advanced stages. They need to go to an ophthalmologist to get their eyes checked to avoid preventable eye problems.

Elimination of DR calls for a determined effort by the government, NGOs, healthcare and eye care organisations to heighten awareness of Diabetes and its complications, extensive screening of the population, especially in rural areas, and provision of free eye care.

In India, the government cannot be expected to tackle the problem of blindness single-handedly due to the sheer size of the blind population. We have an excellent example of public-private partners where NGOs and eye care hospitals join hands with the government to conduct awareness camps to educate people on various aspects of blindness.