How do I give my 4 year old eye-drops; he won't lie still?

2 ways. That work: 1. Put one eye drop in the corner of his eye near his nose and have him open his eye, ..The drop goes in. 2. Pull the lower lid at the outer corner out and down and put in one drop. He doesn't have to hold that still and it works.
Create a shelf. Even adults will flick out a drop by reflex if place directly in the eye. I like to put a finger or thumb at below the eye and tug down on the skin to create a shelf. The drop can be put in that shelf and the skin released. You may need another adult to hold the kid while you do it, but it woorks most of the time.