Her name is Ditzy Do. Great art though.

Derpy makes it sound like she's retarded or something. It sounds mean. It's just her eyes and in the show her name is Muffins.

Derpy name never was in episodes. Unless it's some translation or edit..
Derpy was fan name that was given to pony that was visible in few background images, including old intro )
Lauren Faust pondered Derpy Hooves variant.
First variant of episode, where Dash calls her, actually used Ditzy Doo. Some localizations\translations and edits used fanmade name.Fanmade translation of FiM to russian uses Ditzy Doo, official used Muffins. Finalized episode edit doesn't use _any_ name because a) aforementioned problem b) Ditzy Doo apparently was a trade mark used by other company. In result booth names weren't legal.

Some offer to call her Muffins.

Bobby Curnow stated on June 21, 2014 "Derpy isn't the official name, there is no official name".

that seems a per-network edit (i.e. was done for certain region or channel). It's a first time I see the different eyes in this episode.Provided that those which were on air _here_ officially started to be aired in late 2015, long time after the episode was out.

Awe look at the cute Derpy I want to hug and cuddle her :3

Cute

D'awwwww this is stunning! And wow the improvement from then to now!!

Hooray for Derpy Pony!