。
My eyes tire easily.
Literal
Eye [subject-が] tire-easy is.
疲れやすい is a compound built from the masu-stem 疲れ- plus the suffix ~やすい ('easy to X'). やすい attaches to any verb stem to form an i-adjective meaning 'easy/prone to do X.' Its opposite is ~にくい ('hard to X'). The polite copula です at the end keeps the register formal.