Monoyer Chart

The Monoyer Scale is a tool used to measure visual acuity. It is composed of lines of letters of decreasing sizes, allowing to evaluate the ability of the eye to distinguish details at different distances. Its name comes from Ferdinand Monoyer, a French ophthalmologist who designed it in 1872.

By taking the first letter of each line from the last line, the word obtained is MONOYER, then by taking the last letter of each line always from the penultimate line, the word obtained is FERDINAND, both its first name and last name.

To be exact, it is written Monoyer DM, and DM certainly means Doctor of Medicine.

The other letters of each size do not mean anything and do not have a particular pattern, they are probably randomly selected:

Monoyer
M R T V F U E N C X O Z D
D L V A T B K U E R S N
R C Y H O F M E S P A
E X A T Z H D W N
Y O E L K S F D I
O X P H B Z D
N L T A V R
O H S U E
M C F
Z U

Each line on the scale corresponds to a level of visual acuity, expressed in tenths. Reading the line marked 10/10 indicates normal visual acuity.

Here is a PDF file to download/print: here

For a rigorous measurement, after printing on a 1:1 scale (on a format close to A2) the 10/10 line has a height of 7.3mm

The Monoyer chart (or Monoyer test) is used by opticians for testing visual acuity in patients with impaired eye.

However, this ophtalmologic table to print tends to be outdated and replaced by others like Snellen chart, or more recently by tests on screens, and possibly prescribe visual aids (glasses).

Another limitation is that the Monoyer scale only measures distance visual acuity and does not detect other visual problems such as presbyopia, astigmatism or binocular vision defects.

The recommended distance for a Monoyer Chart is 5 meters.