I didn't see anyone addressing this explicitly, but it seems to me from the subject matter there would be no monetary compensation for a damage to the fetus which does not result in the termination of the pregnancy.
See Bava Kama 49a with Rashi. When the mishna said the value of the fetus, that encapsulated the monetary benefit (to the woman) of the fetus. As such, reparations are deduced by calculating the value of a woman who is pregnant against her value when not pregnant, imagining the value of this woman if she were sold as a slave. And as Rashi explains, being pregnant makes her seem bigger and healthier so she is worth more monetarily. The Tur brings a different method of assessing the mother's value. We assess her as having been weakened more through a violent termination of the pregnancy and therefore worth less than had she gone through a normal childbirth.
But what we see is that the payment concerning the fetus has nothing to do with the value of the actual fetus itself, but rather the value of the woman as concerns the fetus. It is that difference in value of the woman, not the fetus's value, that gets paid.
Being so, I will point out that a blind fetus still serves the purpose of making her look bigger and stronger due to her pregnancy, so there was no monetary loss as concerns the mother's value. She herself also did not become weaker from this act.
A related clarification once we're on this topic: The Aruch HaShulchan in Ch'M 423 2 asks why don't we in fact assess the value of the fetus themselves? He answers that since every pregnancy carries a risk of miscarriage, no buyer pays for a fetus what he would pay for an already born infant. Therefore all assessments are made only concerning the mother.
A similar idea is found in the Perisha as well.