Before going to Iran, my relatives were calling me every day telling me that they were cheshm entezār, literally eye anticipation. Once I got to Tehran, my Neyshaburi relatives were calling to say that they were cheshm be rāh, literally eyes on the way.
Eyes are quite precious and used in many Persian expressions. They are used in expressions of tārof or to sort of "congratulate" someone whose guest has arrived. In the above expressions, eyes are used to indicate that someone is looking forward to seeing you. Cheshm entezār is used when there is more time remaining before a person's arrival. This is kind of the "waiting" period. Now I get frequent messages from cousins telling me that they are cheshm entezār for my next Iran trip. Cheshm be rāh is looking forward, like you are almost there, so their eyes are on the road just waiting to see you. My parents were flying in to see me yesterday, so I told them I was cheshm be rāh.
Another common expression using the eyes is ghadam ru cheshm, literally your step on my eye. This is a very polite, respectful way of saying that someone is welcome (they can step on your eyes. That's how welcome they are!) While I was in Yazd, I met my friend's aunt. She told me that she would love to visit the U.S. one day. I told her ghadam ru cheshm meaning that she was welcome any time, and I would be at her service to show her around or help her with anything else that she needed.
You'll also hear people simply say chashm, eye, as a polite form of saying ok. The most common way to say ok is bāshe. But to be a little more polite say chashm. For example, my cousin asked me to send her the pictures from Iran. I could say chashm or even bāshe chashm. It's also possible to say ru cheshmam, on my eye. This is a much more formal, polite way of saying chashm meaning you are more than happy to do something and will do it from the bottom of your heart.
I think like most people, I cringe at the sound of my own voice, so I don't like to record audio. But since many of you have asked... ru cheshmam.