[TYPO3-mvc] valide field only if there is value in it?

[Daniel Dimitrov]

Hey guys,
I'm wondering if it is possible to use the
@validate EmailAddress

only if the field has a value in it?

If the user fills a value in the form field email, then I want to validate 
if it is a valid email address. If the user leaves the field empty I don't 
want to output an error message.

Should I write my own validators??
Daniel