Ferdinand Monoyer – Know About the Inventor of Eye-test on his 181st Birthday


Ferdinand Monoyer was a French ophthalmologist, who introduced the dioptre in 1872.

Google comes up with an interesting doodle to pay tribute to the popular French Ophthalmologist on his 181st birthday and probably it’s the best time to talk about his good deed due to which millions of people around the world are able to correct their vision.

Have you noticed the alphabetical chart of varying letter sizes hung on the wall at your eye doctor’s clinic? Well it’s not just a chart; it actually aids to get you right pair of corrective lenses.

If you are able to eliminate your blurry vision, it’s primarily because of more than 100 years old, ground-breaking creation of visual acuity chart which was invented by the Ferdinand Monoyer. The chart is also known as Monoyer chart.

Apart from this invention, the French Ophthalmologist is best known for inventing dioptre which is the unit to measure optical power of lens.

Who is an ophthalmologist?

Ferdinand Monoyer was an ophthalmologist which is actually a totally different profession than optometrist or optician.

An ophthalmologist in an eye and vision care specialist and have the license to perform surgery. They are skilled in diagnosing all kind of eye diseases and prescribing suitable lenses.

Ophthalmologist are qualified enough to participate scientific researches related to optical line. Due to such qualification, Ferdinand Monoyer was able to come up with such a great and useful invention.

About Monoyer’s invention:

Monoyer used to run an ophthalmic clinic where he took his innovative idea and used it for the first time. The chart was designed as per the decimal system. He chose right type of font style without focusing on same linear dimensions.

Dioptre denotes how strong the lenses are with respect to focus light on person’s retina. This unit of measure was used for placement of letters. Every row of letters on the chart  represents different dioptre

Some interesting facts about Monoyers’ inventions:

  • Dioptre which was started using in 1872 is still used to measure eyesight.
  • Dioptre is the measurement of the distance of you have to be from the text you read. It is like the distance between you and the text to be read.
  • The most notable invention of Monoyer, the eye test chart represents various dioptre ranging from smallest to largest letter.
  • Monoyer chart which still is used by ophthalmologists around the world was devised long back in 1872.
  • Monoyer chart was the first eye-test to use a decimal technique.
  • Monoyer made sure the letters on the chart are as legible as possible. According to him, if this test is going to determine a person’s vision then it should be clearly readable.

If you clearly look at the Monoyer eye-test chart, you can spot the hidden secret. Ferdinand Monoyer cleverly placed his name on either side of the chart, starting from the second line of the bottom of the chart.

Leave a Reply

Your email address will not be published. Required fields are marked *

You May Also Like