Yoreh Deah Siman 267 Seif 34

לד הִכָּהוּ עַל עֵינוֹ וְחִסֵר מֵאוֹרָהּ, עַל שִׁנּוֹ וְנִדְּדָהּ, אִם יָכוֹל לְהִשְׁתַּמֵּשׁ בּוֹ עֲדַיִן אֵינוֹ יוֹצֵא לְחֵרוּת.

Seif 34

If the master struck his eye and the slaves vision was impaired or struck him on his tooth and it becomes loose, if he is able to use them (where he was struck) he does not go free if not he does go free.