Short sightedness isn’t a disease, yet myopia is the commonest cause of poor sight worldwide. In the west, it is usually no more than a minor inconvenience alleviated by corrective eyewear, but in countries with poor infrastructure it can make the difference between a successful life and one of poverty and dependence. WHO estimates that 153 million people live with uncorrected refractive errors. The personal costs of short sight are significant. Children may be able to read a book by holding it inches from their face, but they can’t read a blackboard. When they grow up they won’t be able to drive. In an increasingly technological world myopia will be an increasingly serious handicap.
How can these children be provided with spectacles?
The gold standard for primary care eye services is assessment by an optometrist, who checks for eye diseases and can prescribe lenses for refractive errors. (The term optician is apparently falling out of favour and being reserved for dispensing opticians). Every high street in the UK has several optometrists, one for every 10,000 people. Sub-Saharan Africa averages one optometrist per million people. Even relatively sophisticated South Africa, with a population of 41 million, has fewer than 300 optometrists. But refraction is only the start. Optometrists take measurements so the glasses will fit the face. Someone has to make the lenses and fit them in the frames. The spectacles have to be delivered. And they have to be affordable in countries where people on average earn only $1 a day. Refraction services are rarely free of charge. Cheap lenses are usually of poor quality. And how do you provide services and deliver spectacles in the bush?
Myopia clearly has a genetic element, and the distribution of short sight – very common in the Far East, much less common in Africa – suggests that bookwork, and these days screen-work, promote myopia. There is no hard evidence, however, and the phenomenon is not fully explained.
One vision charity estimates that 100 million children aged 12-18 in poor countries are going to need glasses if they are to get the most out of their schooling, and 60 million of them lack access to appropriate eyeglasses or to eye care professionals. Their lives will be constrained by lack of spectacles. Unless an alternative service can bridge the gap.
A possible solution is self-adjustable glasses. One version was developed by former professor of physics Josh Silver. He adapted technology used in his Oxford laboratories to produce lenses containing a membrane filled with silicone fluid. Using small syringes on the arms of the spectacles the amount of fluid in the lens, and hence its curvature, can be adjusted to the wearer’s needs and then fixed by turning screws on the frame. The syringes are removed, leaving a normal-looking pair of glasses. With very little training teachers can sit pupils in front of a chart and adjust the glasses until the children can see clearly. Within minutes children have the glasses they need. It’s a one-stop shop for specs for people with short or long sight. Teenagers can refract themselves. Studies in China and Boston show that self-refraction compares well with refraction by a trained optometrist.
In 2011 Professor Silver’s glasses were shortlisted for the 2011 European Inventor of the. Year Award, and won the BMJ’s debate at the Innovation Expo conference to find the idea that would most influence healthcare in the next few years. Yet, four years later, few people have heard of self-adjusting glasses and less than 50,000 of the millions of people worldwide with acuity problems have tried them. So what are the obstacles?
Cost is a problem. Self-adjusting lenses are still more expensive than traditional lenses of similar quality. Robustness has been questioned, though current designs are said to be as able as traditional glasses to withstand the rough treatment meted out by children. Self-refraction may generate a stronger lens than is necessary, leading to headaches and eyestrain. Self-adjusting lenses come in standard frames which don’t permit changing the position to fit the face and match the distance between the pupils. Acceptability is another issue. Currently, adjustable spectacles all have round frames – fine if you fancy a Harry Potter look, but not cool if everyone is wearing the same specs. In some societies, unfamiliarity with eyewear affects uptake of glasses, however provided, and children anywhere can be the butt of teasing. And even in rural Africa teenagers may judge themselves against international norms and feel that they are being offered a second-best solution; not for the rich but good enough for the poor.
Self-refraction and adjustable glasses are not the complete answer to the problem of refractive errors. They will not solve the problem of astigmatism, and without skilled assessment and fundoscopy other eye problems cannot be picked up. But in the absence of optometrists, at least short-sighted kids can get serviceable glasses and those children whose poor vision can’t be corrected by spherical lenses can be identified, and then helped if services exist.
Radical ideas face big obstacles. Does this one have legs? Setting up the self-refraction one-stop shop requires organisation: education, personnel, publicity, planning sessions, training people to supervise them, arranging referral pathways for those who fail self-refraction, collecting data to assess outcomes. It’s simpler than establishing a full-blown optometry services, but still requires significant investment. International agencies and governments are already committed to the optometrist model. Should they introduce an alternative service running alongside the development of conventional services, thereby diverting substantial resources from the long-term solution?
The long-term may be very long. In Malawi the first five local optometrists graduated in 2012. How long will it take this large, poor rural country to establish conventional refraction services for its 16 million people? For governments struggling to provide their people with clean water or threatened by insurgents or epidemics, what is the priority for short-sighted children?