Who created the modern eye test?
Around three quarters of the UK need to wear contact lenses or glasses or have had to have laser eye surgery at some point in their lives. And anyone who has visited an optician to have their eyes tested will be familiar with the rows of letters that get progressively smaller that they’re asked to read during a test. But what you may not be familiar with is the inventor of the test and how our modern-day testing routine came about. Ferdinand Monoyer was a French ophthalmologist born in 1836 who’s greatest achievement was inventing the test we still use to assess eyesight today.
Monoyer was one of the leading ophthalmologists in France, having worked at universities in Lyon, Nancy and Strasbourg until his death in 1912. He was incredibly innovative and created the letter chart that changed the landscape of vision testing. Monoyer was known to change the fonts of particular letters if they didn’t suit him, arguing that if someone’s vision is being tested by it then it needs to be as legible as possible.
The Monoyer chart comprises rows of letters that decrease in size the closer they get to the top, which the patient being tested is asked to read out loud from the largest to the smallest. He even snuck his own name into the chart along the side of each row! With each row of letters, a different dioptre is represented which is a measurement term that Monoyer coined to describe the refractive abilities of the lens. For patients who are able to read the top line correctly – the smallest of all the letters – then their eyesight is deemed exceptionally good.
Snellen and LogMAR
The Monoyer test was rivalled by the Snellen chart which uses symbols instead of letters and was created by a Dutch ophthalmologist of the same name. In fact, the term 20/20 vision came about as a result of the Snellen chart – it’s actually a measurement in feet, while a metric-friendly version would be 6/6. Both tests have since been replaced by many opticians with a LogMAR chart, the Monoyer chart is still considered a vital contribution to the world of ophthalmology. The decision to replace the Monoyer test with the LogMAR chart was due to it being better equipped to detect other deficiencies in the eyes along with short and long-sightedness. The LogMAR test uses the principles of the Monoyer and Snellen charts but has subtle amendments that pick up on discrepancies in vision – it was created by researchers in Australia in 1976.
Before Monoyer added his contribution to eye testing, there were other ways of assessing a person’s vision. Ancient civilisations had their own ways of carrying out eye tests, using their own versions of the modern-day Snellen chart which was to look into the night sky and identify as many constellations as they could. If they couldn’t see the more obvious constellations, their sight was considered to be of a lower standard. The ‘Arab Eye Test’ was the first recorded attempt to measure someone’s vision ability which comprised of distinguishing between two stars – Mizar and Alcor.
Discoveries in Eye Anatomy
These tests were used for several thousand years before a German mathematics genius by the name of Johannes Kepler identified the importance of the retina in 1603. Kepler realised that images reach the back of the eye in an upside-down and inverted way, which the brain then flips so we can make sense of what we’re seeing. This knowledge of the anatomy of the eye changed how we test eyesight and the ways in which we understand how vision works.
The Invention of the Ophthalmoscope
Another German polymath – Hermann Von Helmholtz – created the ophthalmoscope which further revolutionised eye care. This tool is the small stick with a light on the end that we’re familiar with opticians using to check the health of our eyes during a test. It’s been a fundamental part of testing for more than 150 years and allows testers to check the nerve physiology and mechanics of the eyes are working correctly. This invention made Kepler an overnight star and is still used today during eye tests – a testament of how critical this tool is.
No-one can deny how crucial Monoyer’s contribution to the field was – without his innovative ideas, it may well have taken us much longer to perfect how we test vision. His chart and the invention of dioptres had a lasting impact on ophthalmology that has lasted to the present day. It’s recommended that you get an eye test at least every two years to ensure your vision isn’t deteriorating, whether you already wear glasses or lenses or not – if you find that your vision is giving you problems, book a test sooner.