An Adlens innovation means spectacle wearers could soon change the strength of focus on their glasses at the turn of a dial

Although it is often impossible to remember where you’ve left them, it’s increasingly common for people to have multiple pairs of glasses dotted around the house for various purposes.

With a pair for reading, another for using a computer and another to watch the television or drive the car, finding the right ones can be a frustration. But turning the house upside down in the search for the right pair of specs could be a thing of the past thanks to Adlens.

The Oxford-based company specialises in “adjustable focus eyewear” – glasses that can change their strength at the turn of a dial, depending on what activity you’re using them for.

Around 600,000 pairs have been bought around the world in almost four years – including in the developing world, with the eyewear sold for £1 a pair to Rwandans in need of corrected vision via a connected charity.

The “Adlens Adjustables” are based on technology from the 1960s developed by the Nobel prize-winning physicist Luis Alvarez. The distinctive lens system on the glasses is made up of two polycarbonate plates on each eye which slide across each other by twisting the dials at each side. Where the plates sit determines the strength of the lenses.

When they were initially developed in the 1960s, each lens cost $1,000, according to Dr Graeme MacKenzie, director of industry and regulatory affairs at Adlens. Using injection moulding techniques, the company has brought down the price substantially with the flexible glasses now being sold for under £30.

James Chen, a member of a wealthy Hong Kong Chinese family, who co-founded the company in 2005, says: “With this you can have [glasses for the] computer, reading, reading in bed [and] different lighting. Adjustability proved a huge factor.” Where the glasses differ from cheap pairs sold by high street chemists is their flexibility to be changed to whatever the user needs at the time, he said.

Adlens has marketed the glasses as a temporary measure for when prescription glasses are lost or broken and for those with diabetes who see changes in their vision as blood levels fluctuate.

Any fears that the self-diagnosis may damage the eye are unfounded, says MacKenzie. “The visual system is really good at detecting discomfort and if, particularly on this product, if you turn it in and you get it wrong, you will feel it. If you go too far, you will feel your eye straining and you can very easily turn in the other direction.

“What this product does is it takes that exact procedure [with an optician] but it cuts out the external person. You can make a judgment on your own.”

Japan has proved a fruitful market, selling 100,000 of the 600,000 sold so far, with the US, Mexico and Norway emerging as other key sales areas. Not so the UK, however. Only 1,000 pairs have been sold because they can only be bought through optometrists.

Regulations dictate that glasses can only be sold via a prescription from an optometrist unless they are reading glasses, which can be bought off the shelf in retailers such as Boots. “In the UK, the current regulation restricts the sale of our glasses in a way that you don’t have in Japan or in other countries,” says MacKenzie.

Running parallel to the commercial operation is the charity Vision for a Nation, which supplies the glasses free of charge to Rwanda’s health authorities and funds a training programme for nurses to conduct eye tests.

It is estimated that up to 1 million of the country’s 11 million people need glasses, says Chen. Most of those with sight difficulties will need standard reading glasses while between 5% and 10% will be able to get the Vision for a Nation adjustable lenses. Chen, who says that vision issues have a low priority in the developing world, hopes to expand the project to Bhutan in the future.

“I would not have even started this project if all I was thinking about was making money from this,” he says. “If all I did was make a lot of money, sold a lot of these things in the developed world who already have access to glasses, I would feel I had not succeeded. The benchmark to success is that we are able to bring access to vision and to bring glasses to people who otherwise would not have been served and I think that is something that informs everything that we do.”

By charging £1 a pair, the glasses are given a value to the person buying them as opposed to being given away for free, says Chen. That money is then put into a fund to deal with other eye-related problems such as cataracts.

Chen’s investment in the project – he is co-founder, owner and board member at Adlens and a trustee of the charity – has been put in the millions.

The next product to come to market from the company is a much more elaborate version of the adjustable glasses. Pairs of chunky and fashionable glasses – which appear identical to conventional eyewear – have a discreet dial on each of the arms which can switch between three different pre-set strengths.

The new range uses a different type of technology to their stablemates in that fluid is injected into the lens to change the curvature. Instead of having to test and adjust to the strength, the presets switch the power of the glasses through the three different prescriptions depending on what the wearer is doing.

Dr Rob Stevens, the company’s chief technology officer, says Adlens are aiming for people over 45 who are unhappy with their varifocal lenses, which have invisible lines between the reading and distance part of the lens.

The new range of Adlens glasses have a discreet switch in the arms to vary between three different preset strengths. They cost $800 and are in the early stages of sales in the US.

The company claims that capturing 3% of the existing market for varifocals in America would be worth around $180m. If successful, they could go on sale in the UK next year.