Self-adjusting glasses

Although an estimated 60-70 per cent of people in the UK wear glasses, only around five per cent of people in developing countries do, due to the cost of the glasses and a lack of access to eye specialists.

Prof Joshua Silver, director of the Centre for Vision in the Developing World at Oxford University, has devised glasses which can be adjusted according to the severity of a person’s sight problems.

Plastic syringes full of silicone oil can be attached to each side of the thick frames, allowing the wearer to pump as much liquid into the glasses as needed to correct their eyesight. Those with more severe vision problems pump in more and those with milder problems pump in less. The syringes are then detached.

A pair of the glasses costs around $19, but Prof Silver hopes this cost can eventually be reduced. He aims to start by distributing a million pairs of the glasses, which are made in China, in India in the next year.

Prof Silver became interested in the emerging area of adaptive optics in the mid-1980s. After considering the way the eye-brain adaptive optical system works, he suggested that self-refraction with suitable adaptive lens eyeglasses could be a useful procedure for correcting refractive error, after trying such a procedure on himself.

He created several adaptive lens eyeglasses (adaptive eyewear), and then carried out research supported by the UK’s Department for International Development.

Tonight, Prof Silver will deliver a Gates Distinguished Lecture, which is open to the public, entitled ’How do we really bring vision correction to those that need it in the Developing World?’ in the Cambridge Union Society debating chamber from 6:30pm-8:00pm.