text: Brook, 30, who moved up two weight divisions to face the unbeaten middleweight champion, will have an operation in Sheffield on Monday, promoter Eddie Hearn said.
  He suffered the injury in the second round in London and had blurred vision before being stopped in round five.
  It was Brook's first defeat in his 37th professional fight.
  Hearn paid tribute to Brook for accepting the challenge against Kazakhstan's Golovkin, who has 33 knockouts from 36 fights, including 23 in a row.
  "Fans always want to fighters step up and fight the best and he did that," he said.
  "Kell stepped up from welterweight to middleweight. He wanted the big fights and it was a hell of a fight. I think Kell deserves lot of respect."
  Hearn told BBC Radio 5 live's Sportsweek that Brook's trainer Dominic Ingle was correct to throw in the towel to signal defeat in the fifth round.
  "Kell traded with him and had a real go but it was absolutely the right decision from Dominic Ingle," the promoter said.
  "I know there were a few boos from the crowd but he knows his fighter more than anyone and that kind of injury can get worse and worse in a fight and ultimately end someone's career."
  Having initially questioned his trainer's actions, Brook agreed the day after the defeat that Ingle had been correct.
  "He's like a father figure. It was the right decision and I can fight another day," he said.
  "I was getting caught, and getting caught. It could have ended up seriously bad."
  In beating Brook, Golovkin recorded his 17th world middleweight title defence.
  Ex-world heavyweight champion David Haye on BBC 5 live:
  "That stoppage was absolutely spot on. You've got to realise, Kell Brook is a current welterweight champion - he had no business taking that onslaught on the ropes.
  "I'm so happy Dominic Ingle did that and didn't watch his fighter get drilled to the canvas, because give it six months and he's back in the ring, he's still earning money for his family, he's still defending his welterweight title.
  "Great bit of corner work by Dominic Ingle - the best I've seen for a very long time."
  Before he was taken to hospital, Brook spoke of his intention to return at light-middleweight.
  Hearn told BBC Radio 5 live's Sportsweek there are numerous options for the Sheffield fighter when he considers a return to the ring.
  "He is still world champion at welterweight. It's going to be difficult for him to go back to 147lbs but in terms of worldwide stock, I think Kell's rose considerably," the promoter said.
  "[US TV network] HBO asked me if I would do the re-match with Golovkin but I can see him [Brook] returning to light-middleweight, there are some huge fights out there for him.
  "There is the Canelo [Alvarez] fight, the Amir Khan fight should have happened a dozen times and hasn't, maybe they feel it is the right time for that, there are other world champions out there at light-middleweight.
  "The Golovkin re-match, if people want to see it in time to come, who knows? But it is not something that is going to happen in the very near future."
  Hearn added that a fight with Britain's Khan, a former light-welterweight world champion, would be his own preference.
  "They don't like each other and as a promoter there is nothing better in a build-up than two fighters that don't particularly like each other," he said.
  "The Canelo fight is one of the biggest in world boxing but for now it is about getting that eye tidied up, having some rest and probably returning in the spring/summer of next year."
  Meanwhile Hearn's father, the veteran promoter turned World Snooker supremo Barry Hearn, condemned a tweet from British middleweight champion Chris Eubank Jr to Golovkin after the fight.
  Eubank challenged Golovkin to a bout and, with reference to Brook having moved up two weight divisions, said it would be "with a real British middleweight" before adding "my corner don't own towels".
  Hearn senior described the tweet as "shameful" and wrote: "Possibly the most ignorant comment I have ever read on social media."
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target: Kell Brook will have surgery on the broken eye socket he sustained in Saturday's defeat by Gennady Golovkin.