Anthony Joshua was taken to hospital for assessment following his loss to Oleksandr Usyk on Saturday night.
The British-Nigerian boxer is suspected to have suffered eye socket damage.
Joshua's promoter, Eddie Hearn, has revealed that he could not see properly after the ninth round.
By the 10th round, 'AJ' was carrying a black and swollen eye, as Usyk continued to batter him at the Tottenham Hotspur Stadium.
The Ukrainian almost knocked him down in the final seconds, but won via unanimous decision 117-112, 116-112 and 115-113.
"He will go to hospital. I don't know if he has broken his eye socket, it doesn't look great.
"He said he couldn't see after the ninth round, obviously he was getting tagged a lot as well.
"His power looked like it had left him, the tank was empty and it was only heart which kept him on his feet in the 12th round," Hearn said afterwards.