Optime-Trick by Dave Bartlett

It’s easy to remember because of the college degrees: PH.D and B.A.
These are the key letters that you need to know. If you look at the third line of each eye chart, the first letter of the line is a KEY LETTER.

Place the eye charts in the PHDBA order with the “p” chart facing the audience first.

PERFORMANCE
In performance, you’ll have someone think of a letter in the alphabet. You’ll show them the eye charts and ask if the letter is on each chart.