I would set her up with something she can wash her head in, and get Vetericyn spray set it to mist, and mist her eye as she walks by. I had to do that with Carmella once. She is a bit shy of people. So I'd just do that. It's best to get on it right away to prevent infection.
I suspect something got in her eye and is irritating it.
Vetericyn makes an opthalmic gel, you could use a mild saline solution to rinse it, too.
Does she have water deep enough to rinse her head in?