being myopic shouldn't reduce your chances at the interview as long as its under 500 as stated on the career website. most of my course mates don't have perfect eyesight and many seniors/pilots i've met wear specs like me.
however i do think they are very strict about the limits (both myopia and astigmatism pre lasik) listed
a word of advice.. please prepare before going to the interview. wikipedia is a good place to start! be humble, dress well and speak clearly and u should get through the first interview. you should of course read this entire thread too to find out more about the interview process and what is expected of you. lots of good info here.. although some might be outdated, but its still good to know
gd luck to those applying and those who got rejected, don't give up on your dream!