x Abu Dhabi, UAESaturday 22 July 2017

Blindness could be avoided in most cases – so why isn’t it?

There are 285 million vision-impaired people in the world, of whom 39 million are blind, but 80 per cent of blindness is avoidable.

Tomorrow is World Sight Day – the day when the world focuses on the issue of avoidable blindness.

For those of us with good sight, it is hard to imagine the personal impact of being blind: the loss of independence and economic security, the inability to see your family and friends, to read a newspaper or simply watch a movie.

There are 285 million vision impaired people in the world, of whom 39 million are blind.

The extraordinary fact is that 80 per cent of blindness is avoidable, either because it is treatable or could have been prevented in the first place. Globally, the top causes of blindness are cataract (the lens of the eye becoming cloudy), glaucoma, retinal disease (particularly diabetic retinopathy and macular degeneration), corneal scarring from xerophthalmia (vitamin A deficiency) and trachoma (an infectious disease passed on by flies).

In resource-poor countries, a huge impact on rates of blindness can be made by simple public health interventions.

Availability of clean water together with education about hygiene can reduce both trachoma and vitamin A deficiency. Immunisation campaigns against measles and rubella can prevent blindness from corneal scarring and from congenital cataract.

In the UAE, malnutrition and infectious diseases no longer feature as causes of vision loss, but even in such a highly developed country there are eye diseases that, undetected and untreated, can steal your sight.

Cataract is the most common cause of vision impairment in the UAE, when the clear lens of the eye becomes opaque causing blurred vision and glare from bright light.

For adults, cataract surgery is now a quick and reliable intervention which can be carried out under local anaesthesia. For children, the surgery is more challenging and requires general anaesthesia but is now available by skilled surgeons at specialised centres within the UAE.

The two stealthy thieves of sight are diabetes and glaucoma.

Unlike cataract, where sufferers notice a decline in clarity of vision and glare in bright light, people with diabetic eye disease or glaucoma can be completely unaware that they have problems until the eyes have become severely damaged.

Awareness of this means that all diabetic patients need examination of their retina each year, either by an ophthalmologist or by professionally graded photographic retinal screening, to find treatable disease.

Diabetic eye disease is the leading cause of blindness in the working age population of many developed nations, since diabetes has a prevalence of 18 per cent in UAE – the 11th highest in the world – its effects on the population of the UAE will grow in the next few decades, as the population ages.

Diabetic eye disease of any sort – such as Diabetic Retinopathy – is present in 50 per cent of people who have had diabetes for 10 years and 90 per cent of those with the disease for 20 years.

Lifestyle factors can reduce the burden of diabetic eye disease: an active lifestyle, weight loss, consistent diabetic control and avoiding smoking are key ways in which people with diabetes can protect their eyes.

Once disease is detected it can be treated using specialised retinal lasers or with injections of specially engineered molecules. Severe cases may need vitreo-retinal surgery. Treatment of diabetic eye disease can reduce the progression of the disease, preventing severe vision loss or blindness by up to 90 per cent.

Glaucoma is the other main silent blinding disease, where high eye pressure damages the optic nerve and patches of the field of vision become permanently lost. People with glaucoma do not notice the changes but eye tests that include eye pressure, examination of the nerve health and a visual field test can detect glaucoma, enabling its treatment before vision loss is significant.

This combination of tests needs to be done at an eye clinic as it is not generally available at an optical shop.

Anyone can develop glaucoma but adults with glaucoma and people with affected family members are particularly at risk. Modern treatment methods mean that when detected early the disease is eminently controllable.

The challenge for the UAE is to make sure that people know the importance of accessing high quality eye care for glaucoma screening, and that people with diabetes undergo retinal examination annually.

At present people with diabetes in the UAE only have an eye test if they are asked to by their diabetes doctor or are motivated to organise it themselves.

In contrast, in countries such as the UK, disease registers are kept to ensure that every patient in whom the diagnosis is made is systematically called up each year for retinal screening photographs which are professionally graded, with those at risk of vision problems being seen by an ophthalmologist for assessment and treatment.

A national professional photographic retinal screening system could ensure that all diabetic retinal disease in the UAE is diagnosed and treated early.

Finally, although much eye disease is treatable, there will always be some individuals for whom blindness cannot be avoided.

As a community we must provide the best possible opportunities for vision impaired people both in education and employment, enabling each individual to develop their skills and reach their full potential.

Dr Clare Roberts is medical director at Moorfields Eye Hospital Dubai