How Ferdinand Monoyer created the modern eye test

Tuesday, 9 May 2017 by Callan Smith-Sheerin

You may have noticed the cool Google doodle celebrating the 181st birthday of Ferdinand Monoyer today. But, just who was Ferdinand Monoyer and why did Google honour him?

Monoyer was a French ophthalmologist born in 1836 who worked at the universities of Strasbourg, Nancy and Lyon until his death in 1912. He is best-known for inventing a test for eyesight that he named after himself. This test still forms the basis of the one used today, although there have been developments made since.

The Monoyer chart consists of rows of letters that decrease in size as you get nearer the top. The patient is asked to read each line out, starting with the largest letters first. Each row of letters represents a different dioptre; a measurement coined by Monoyer to describe the different refractive powers of a lens. monoyer-test

When you have an eye test, if you manage to read the top line correctly, you have particularly good eyesight. Take a look at the image here for an example, you may also have noticed that Monoyer snuck his own name into the chart!

This test was rivalled by the Snellen chart, which used rows of symbols originally before converting to letters. Both tests have been replaced in many opticians with the LogMar chart. This chart is useful for detecting other deficiencies in vision as well as short and far-sightedness.

Without Monoyer’s ideas, it may have taken longer for us to perfect eye tests. With both his chart and the the invention of dioptres, Monoyer made a vital contribution to opthalmology and his impact has lasted to the present day.

If you’re having any trouble with your eyesight, even if you’re already wearing contact lenses or glasses, make sure you get an eye test as soon as possible. We recommend getting an eye test every two years as a minimum.

More information on eye tests

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