I think it's literal. He says that her hand hit his eyes. Pressure on the eyes causes a sensations of sparkles of light, called "phosphenes." This is sometimes called "seeing stars."
James M. Barrie writes about phosphenes when he says "If you shut your eyes and are a lucky one, you may see at times a shapeless pool of lovely pale colours suspended in the darkness; then if you squeeze your eyes tighter, the pool begins to take shape, and the colours become so vivid that with another squeeze they must go on fire."
"The Surprising Adventures of Baron Munchausen makes whimsical reference to this, suggesting that the Baron was able to fire a gun by using the "sparks" you see when you hit your eye: "In an instant I took my gun from the corner, ran down-stairs and out of the house in such a hurry, that I imprudently struck my face against the door-post. Fire flew out of my eyes... I soon came within shot, when, levelling my piece, I observed to my sorrow, that even the flint had sprung from the cock by the violence of the shock I had just received. There was no time to be lost. I presently remembered the effect it had on my eyes, therefore opened the pan, levelled my piece against the wild fowls, and my fist against one of my eyes. A hearty blow drew sparks again; the shot went off, and I killed fifty brace of ducks, twenty widgeons, and three couple of teals."