It's often used to express:
* Empathy or sympathy: Like "Oh dear" or "Oh my goodness" in English.
* Surprise or amazement: Similar to "Wow" or "Amazing."
* Affection: In a more intimate context, it can be a term of endearment.
The literal translation is "Oh, my eye," but it's important to remember that language is nuanced. The exact meaning of "Ya einy" will depend on the context and the tone of the speaker.