Here are some examples of how it's used:
* "She has an eye for detail." This means she's very good at noticing small things that others might miss.
* "He has an eye for fashion." This means he has a good sense of style and can put together fashionable outfits.
* "The photographer has an eye for capturing beauty." This means the photographer is skilled at finding and photographing beautiful things.
The "eye" in this idiom refers to the ability to perceive and discern, often with a specific focus or area of expertise.