Twisted Word Verification

WTF is the deal with the twisted word verification? I wholly get the idea that random letters eliminate spam from my website. I do not, however, understand why they must be twisted. Is it possible that spammer programs do not have the ability to read these letters as long as they are distorted?

It's good to know that all the legitimate commenters are crosseyed-squinters like myself.
Furthermore, I invariably get stuck with the long ones. 8 letters or more. I assure you that I have fouled up more than one attempt.
Dyslexics - you have my deepest sympathy.