They are standard pattern humanoids, right? They do not seem to have anything exotic in their biology, or at least that hasn't been shown. No wonky superpowers, no inherent magic, no exotic physiological quirks.
Should this not be trivial? Step 1: "ring, Planetary scan, collect and analyze biological data." Should take at most several minutes. Step 2: "Ring, fabricate an eye cloning machine and an autosurgeon". Step 3: program autosurgeon to remove the scarred / healed over tissue, then jam the clones eye into the raw eyesocket, and use PHR to heal everything together. Unless it doesn't regenerate severed nerves, in which case its utility drops greatly , but since it seems to heal broken bone, this might not be a problem.
Seriously, I get it, and there are a lot of reasons to want a good doctor in the corps, but demonstrated ring capabilities should make this issue quite trivial, really. Absent wards, acquiring data via planet-wide scans is something Paul has done.