There's always a lot of excitement surrounding a movie prequel and the ways it might answer questions that fans have about a series. Going into Captain Marvel one of the biggest questions fans were expecting to get an answer to surrounded how Nick Fury lost his eye. The film eventually gave us the answer, though not in the way many were likely expecting. Although, it seems that, for the most part, what happened was a foregone conclusion.
It was a somewhat anti-climactic, and yet hilarious, answer, as Nick Fury got scratched by an alien creature called a Flerkin, which doesn't sound nearly as impressive when you realize a Flerkin perfectly resembles a house cat. However, Captain Marvel co-director Anna Boden says that while we might not have seen this moment coming, it was really the most obvious scenario under the circumstances...
People ask if we always knew that the Flerkin was going to be responsible for Nick Fury losing his eye, and we didn’t know it would happen exactly that way, but it seemed pretty clear that when we had a Flerkin in this movie, it was going to be responsible for taking Nick Fury’s eyes out.
Anna Boden had previously admitted that there was a lot of discussion of different ways that the lost eye could have happened. However, in the directors' commentary of the Captain Marvel Blu-ray she indicates that, really, one way or another, there was never going to be another source of the lost eye.
And really, if you have a character in your movie that looks like a domesticated feline but is actually a viscous space alien creature with a pocket dimension in its mouth full of killer tentacles, how the hell are you going to have anything else be part of the iconic moment?
Of course, knowing that the Flerkin would be responsible for the lost eye and knowing exactly how the scene would play out are not quite the same thing. Anna Boden says that they didn't know it would happen exactly like that at the beginning, so there was likely still a lot of brainstorming of ideas even once they'd settled on Goose the cat/Flerkin being the source.
The only reference previously made to the events of Nick Fury's injury in the Marvel Cinematic Universe come in Captain America: The Winter Soldier when Fury says the loss came from trusting someone. In Captain Marvel, Fury actually speaks to Goose after discovering what she really is, and says he's trusting the creature not to eat him.
Instead of revealing what really happened, Fury lets everybody else start their own rumors, which he conveniently avoids confirming. The actual cause of the damage isn't ultimately important to the character, though the fact that he lets it remain a mystery very much is in character for the man that we know.