As alluded to by DoubleAA, the Rambam writes (Hovel uMazik 1:3)
The Torah's statement Leviticus 24:20: "[eye for eye ...] Just as he caused an injury to
his fellowman, so too, an injury should be caused to him," should not
be interpreted in a literal sense. It does not mean that the person
who caused the injury should actually be subjected to a similar
physical punishment. Instead, the intent is that he deserves to lose a
limb or to be injured in the same manner as his colleague was, and
therefore he should make financial restitution to him.
then goes to explain it from different verses. He continues in 1:6
Although these interpretations are obvious from the study of the
Written Law, and they are explicitly mentioned in the Oral Tradition
transmitted by Moses from Mount Sinai, they are all regarded as
halachot from Moses. This is what our ancestors saw in the court of
Joshua and in the court of Samuel of Ramah, and in every single Jewish
court that has functioned from the days of Moses our teacher until the
The Rambam then goes and describes the five payments made by someone who injures his fellow: pain, unemployment, medical expenses, unemployment and damages.