Paz comes to mind obviously. He broke his neck and then won a title afterward. Greb's trouble with his eyesight is well documented.
Langford beat Tiger Flowers whilst close to blindness. Barrera has wins over Morales, Juarez and Ayala with that mad metal plate thing in his head. Sugar Ray Leonard famously came back from eye surgery. Holman Williams basically fought a whole career with very fragile hands which had supposedly been repeatedly broken in the early part of his career. Battling Siki came to the LHW title inspite of his being a totally mad *******.
There's Calzaghe and his later career hand issues. Shannon Brigg's asthma. Corey Sander's was beaten so badly by Andrew Golota that he went blind in one eye. Kept fighting.
Yes and yes! It's not as dramatic as it sounds, i believe, the controversy was more about the burst blood vessels the insert was protecting than the tiny insert itself.
I personally think it's quite impressive that Cleveland Williams came back to fight for the heavyweight title after what happened to him. http://vault.sportsillustrated.cnn.com/vault/article/magazine/MAG1079257/index.htm
Holyfield's health problems that forced him to retire after the first Moorer fight. Archie Moore's ulcers that forced him out of the ring for nearly a year when he was a fast rising middleweight prospect.
Harry Corbett ,British Featherweight Champion 1928-29 ,fought the last four years of his career blind in his left eye ,after a loose lace damaged it in a fight.