New type of glasses with adjustable focus
IT’S a problem familiar to many – the struggle to focus on close-up objects such as newsprint or embroidery.
And some people even face the added frustration of having to carry spectacles of varying strengths to allow them to carry out different tasks.
But a British company has come up with a solution – spectacles on which the focus can be altered in the same way as on a pair of binoculars.
A tiny dial on the arms of each pair of the Eyejusters glasses enables the wearer to bring whatever they want to look at into sharp focus.
Creator Owen Reading explained: “Lots of people need reading glasses but they need glasses with lots of different strengths.
“Eyejusters replace the need for multiple pairs of reading glasses, by covering the whole range from 0 to +3, which is the strongest over-the-counter product.
“You can put them on and just turn the dial until what you want to see comes into focus. They are much like adjusting binoculars.”
Reading came up with the idea with friend David Crosby, who studied physics at Oxford with him.
The concept is simple: the lenses in glasses work to focus images by changing the direction of light beams entering them. When a person with long sight wants to look at an object that is very close to them, they will need fat lenses with a highly convex “bulging” shape. When they want to look at something further away, they will need thinner ones with a less convex shape.
Eyejusters work because each lens in the spectacles is actually made up of two, and the pair slide past one another as the dial is turned to give a different shape.
Reading said the idea behind variable-focus glasses had been around since the 1960s but Eyejusters was the first to use the sliding lens concept.
He and Crosby started with a product aimed at customers in poorer countries, where millions struggle to get a pair of the right strength glasses. But last year they decided to focus on the British market, too.
Eyejusters are made at a UK factory and cost £70 (R1 205). They are available from the company’s website.