Vision testing

A few weeks ago I was reading about the history of the eye chart for vision testing and the different forms for non-literate or children to use. I can't find that article - looking for it... I found this:
https://www.aao.org/eye-health/tips-prevention/eye-chart-facts-history

I was thinking that I should include something to learn about vision testing instead of this post just including a cartoon...

You may have to look at this one for a moment or two ... or maybe you only have to do that if you are sleep deprived and it makes sense immediately to everyone else!