Albert Barnes Commentary Exodus 21:26-27

"And if a man smite the eye of his servant, or the eye of his maid, and destroy it; he shall let him go free for his eye`s sake. And if he smite out his man-servant`s tooth, or his maid-servant`s tooth, he shall let him go free for his tooth`s sake." — Exodus 21:26-27 (ASV)

Freedom was the proper equivalent for permanent injury.