Amanda Serrano ’s title defense against Nina Meinke on Saturday in her home country of Puerto Rico was canceled at the last moment because the champion has an eye injury. Jake Paul , her promoter, said she has an “exposed cornea,” which means it is damaged. Neither he nor Serrano said how or when she suffered the injury. A tearful Serrano, who cherished the opportunity to fight in front of her fans,  was clearly devastated as she and Meinke stood in the ring in San Juan for the stunning announcement. She said she was willing to do battle despite the injury but doctors nixed the fight after she failed an eye exam. “I’m so sorry