“An eye in place of an eye, a tooth in place of a tooth, a hand in place of a hand, a foot in place of a foot.” 21:24
An eye in place of an eye – One who causes the loss of an eye must compensate him for the worth of his eye. For instance, if he were sold as a servant he would be worth less with only one eye than with two eyes. The one who inflicted the wound must compensate him the difference. This is true of all of the cases mentioned in the pasuk; the intent is not the severance of the actual limb, as our sages have explained in Masechteh Bava Kama 84b. – Rashi
He must compensate him the monetary value of the eye… -Rashbam
The reason the Torah expresses the punishment as if it expected the literal removal of the eye, is because that would be his fitting punishment measure for measure. Our tradition however, teaches us that in reality one must only pay the value of the eye… - Sforno
This verse, though widely quoted, is frequently misunderstood. The Oral Law makes it abundantly clear that the punishment is not for the criminal to lose his own limb, but rather, to replace the missing limb through monetary compensation. The various commentaries must be studied to appreciate why this understanding is not a departure from the literal meaning of the verse in order to appreciate the interconnectedness of the Written and Oral Law. An excellent elucidation of this point is offered by the classic commentator Rabbi Yaakov Meklenberg, in Ksav V’kabblah.