open (one's) eyes
1. To see or realize the truth about something. Open your eyes, Stan—they're just using you for cheap labor!
2. To cause one to see or realize the truth about something. The documentary really opened my eyes about the conditions in that country.
open one's eyes
Become or make someone aware of the truth of a situation, as in It's time you opened your eyes to the politics of this office, or The trip to Zimbabwe opened her eyes to the difficulties faced by developing nations. [Second half of 1800s]