C. F. Keil and Franz Delitzsch on Exodus 21:26-27

Exo 21:26-27

But the lex talionis applied to the free Israelite only, not to slaves. In the case of the latter, if the master struck out an eye and destroyed it, i.e., blinded him with the blow, or struck out a tooth, he was to let him go free, as a compensation for the loss of the member. Eye and tooth are individual examples selected to denote all the members, from the most important and indispensable down to the very least.