system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do all vision charts start with a large capital E?
gpt
When the Snellen chart is used for a basic assessment, the order of the letters doesn't really matter--the variation starting with E just happens to be commonly used by manufacturers. (There's little reason to deviate from it.) If you want to seriously test someone's ability, especially when fraud is a concern, nowadays a random selection is used rather than a fixed chart.