What do a 16th century Pope, Japanese military pilots and a founding father of the United States of America have in common?
Not very much, you might think. But in fact, they were all involved in some way or another with the science of optics, and played key roles in the lengthy historical development of improvements in the ways we see today.
Here, we explore the history of vision correction from the first spectacles to the use of lasers to improve sight, and pinpoint the pioneering inventions that eventually led to laser eye surgery being a hugely popular choice for millions of people wanting better vision without glasses or contact lenses.
The history of eyesight correction starts in Rome...
The Early Days – a timeline
- Precisely when the first instance of spectacle use as we now know it was recorded is a little (ahem) blurry. However, notable Roman philosopher Seneca was known to have used water-filled objects to magnify texts he was studying all the way back in 4BC. Needless to say, it’s not exactly the ideal solution to a very common problem…
- Somewhere around the 12th Century AD, there were reports of eyeglasses in historical texts from the Middle East, China and Europe, although their lenses were crudely fashioned from rock crystal and offered little accuracy in terms of a prescription
- These early prototypes were only ever used to magnify images for long-sighted people; it wasn’t until 15th century Italy that lenses were made with a convex surface, for those of us wrestling with short-sightedness
- Perhaps the most famous ‘early adopter’ of eyeglasses for short-sightedness was 16th century Pope Leo X: he wore new-fangled convex lenses while hunting, and was convinced that they helped him see better than his fellow hunters
- Around the same time as old Leo was out hunting with his enhanced vision, master spectacle makers in London formed their own Guild, complete with Royal Charter, known as The Worshipful Company of Spectacle Makers. The guild is still in force to this day, providing training, qualifications and guidance for those whose careers lie in optical laboratories
Important developments in the history of eyesight correction
You may be familiar with the concept of bifocals or varifocals, designed to provide sharp vision at both long and short distances – but did you know that it was Benjamin Franklin, founding father of the United States of America, who invented the bifocals?
Precisely when he came up with the idea is unknown, but as he lived from 1705-1790, we know that it was sometime in the 18th century.
Franklin pulled off this masterstroke simply by splitting two lenses – one for long-sightedness and one for short-sightedness – into semi-circles, and fixing them together in a frame. In this way, when he looked down to read, he was looking through the lens that corrected for close work.
Spectacles for both long vision and close work are far more sophisticated (and aesthetically appealing) nowadays, but this type of lens – often called the Franklin Split, even now – is still used occasionally to correct complex prescriptions that require two very different elements.
- The eye test as we know it, with its definable unit of lens requirement measurement – the dioptre, which we still use today – was invented by Frenchman Ferdinand Monoyer in 1836
- The dioptre unit enabled much more precision in lens making and dispensing, and Monoyer is credited with introducing the letter chart to establish the dioptric power needed in a patient's lenses
- In much the same way that we now read letters from a poster at the opticians, 19th-century French scientists used myriad complex calculations to work out how bad a patient’s eyes were from what they could read on Monoyer’s version of the chart
- Throughout the 19th and 20th century, testing and lens-making continued to become more precise, and glasses quickly evolved into the standard way by which opticians aimed to improve vision for the masses
- Fundamentally, little changed in terms of new ways to correct sight until the 1930s, when the idea of physically correcting the eye itself started to become a reality
You’d be forgiven for thinking that the idea of corrective eye surgery was a more recent invention; after all, it involves extremely precise calculations and highly sophisticated technology, including lasers.
Actually, though, theoretical papers were being written about the possibility of bettering sight by changing the shape of the cornea – the domed front portion of the eye – as early as 1936.
It’s the cornea, along with the lens inside it, that focuses light entering our eye, and in turn determining how well we can see. If the light doesn’t hit the back of our eye in quite the right place, our vision will not be as sharp as it could be.
Think of it as like being in a hall of mirrors; some mirrors make you look shorter or taller, some make you look fatter or thinner, and it’s the curvature of the mirror that decides what you will see.
In the same way, if your cornea is curved too much or too little, the image you see will be slightly distorted.
- In 1896, Dutch ophthalmology teacher Lendeer Jans Lans realised that the cornea was responsible for vision problems, and so he set his mind to working out how this could be fixed
- Lans never got further than the theory – but, just a few decades later in the 1930s, a Japanese eye doctor called Tsutomu Satu performed the first corneal reshaping surgery on military pilots
- Satu’s pioneering early surgeries managed to alter vision by up to 6.00 dioptres (that’s a lot!), but his method of making incisions in both the front and the back of the eye resulted in major problems down the line for patients who went under Satu’s knife, and his methods were quickly abandoned as a reliable way of correcting vision for the masses
- Fast forward to the 1960s, and Colombian eye surgeon Jose Barraquer performed what is regarded to be the first effective corneal reshaping for the correction of both long and short-sightedness
- Of course, the use of lasers was still a fair way off at this point; Barraquer used a cryogenic technique instead, removing a thin layer of the cornea and freezing it so that it could be manually reshaped before replacing it on the eye
- Although Barraquer’s method was refined and improved over time, it was still a crude solution compared with the infinitely precise surgeries known and used today
The modern era
The 1970s brought us many much-loved inventions – not least the Post-It note and the Rubik’s Cube – but in terms of corrective eye surgery, it was the invention of the excimer laser that had the most impact.
- Initially developed for precise jobs like making microscopic circuits in microchips, the excimer would eventually prove to be an optics revelation, heralding better vision for millions of people across the globe and offering the first genuinely widespread alternative to glasses and contact lenses for millions of customers
- It wasn’t until 1980 that IBM scientist Rangaswamy Srinivasan made the breakthrough discovery that the excimer laser could cut organic tissue without the risk of heat damage. This made it the perfect solution for performing highly accurate incisions in a delicate structure such as the human eye
- The first performance of this modern laser eye surgery procedure took place in 1983, when the excimer laser was used to physically reshape the cornea
- Known as ‘photorefractive keratectomy’ (or PRK), the technique became a jumping-off point for scientists to develop different ways of using the excimer laser in eye surgery. A new era in vision clarity had truly begun!
Before long, LASIK (laser assisted in-situ keratomileusis) was introduced as an alternative. This method used a very fine tool to cut a small flap on the surface of the eye, exposing the different layers of the cornea for the laser to reshape, before the flap is delicately replaced and left to heal.
- By the 1990s, the technology behind all this was coming on in leaps and bounds, and new techniques were continually being developed - not least the use of the laser itself to make the initial incisions on the cornea, rather than a blade
- With the digital revolution came the ability to use ever-more precise computer programming to calculate exactly where to implement the laser, allowing for eye movement during surgery and taking into account the very individual shape of each patient's cornea
- This technology, known as wavefront, allows for better results than ever before by mapping the cornea in 3D, highlighting the shape of the front of the eye in microscopic detail
- With this information, the surgeon can tailor the treatment to get the very best results for each individual patient. Wavefront mapping also reduces the risk of issues with night-time vision such as halos or glare around lights
Modern wavefront mapping drastically reduces light glare and haloing in post-surgery vision
- Today, with laser eye surgery becoming an ever-more popular choice for vision correction, the ways in which these cutting-edge techniques can be deployed to rid people of glasses or contact lenses has grown as fast as the demand for it
- Cataract surgery - among the most performed surgeries in the UK, where the eye’s lens in replaced due to it becoming cloudy over time - has been modified for people wishing to see both near and far without the aid of spectacles
- Lenses can now be replaced with ones tailor-made to enable the eye to focus at all distances on its own
- Normally, by around the age of 40, the ability to see close up diminishes, so regardless of whether you need glasses for long distance, close work will require some assistance - refractive lens exchange enables a tailor-made synthetic lens to replace your own, allowing crystal-clear vision at any distance
- Laser surgery has also evolved to be even less invasive, with the SMILE technique using keyhole incisions to enable vastly increased precision, faster healing times, and less uncertainty around how the vision will settle with healing
All of these developments mean that more and more people can be considered as suitable candidates for laser eye surgery, with all but the most complex prescriptions corrected by these wonderful leaps in technology.
As for the future? Right now, a Canadian company is in the process of developing the next evolutionary step in lens replacement: synthetic lenses will soon be capable of using dynamic movement in the muscles of the eye to enable sharp focusing at a much wider range of distances and angles than ‘stock’ human eye lenses are naturally capable of.
Scientists hope to have the technique available by 2020, so we’ll keep our eyes peeled - as it were - for any new developments!