Actor Samuel L. Jackson was forced to change his method of learning his lines when he signed on to play Marvel movies' regular Nick Fury because the character's eye patch played mind games with his memory.

The 65 year old, who plays the leader of the Shield international intelligence agency in superhero films like The Avengers, Captain America and Iron Man, admits he had a hard time adjusting to Fury's sight issues.

He tells U.S. breakfast show Good Morning America, "The only problem I didn't discover until we did Captain America, the original Captain America, because I very seldom had very much to say, was that I sat at home and did all my studying and when I got to work the next day, I was having difficulty saying all the lines.

"I could only visualise half the page. I realised that when I cut my eye off with the patch, I cut off half off my sensory perception for learning. So now when I learn lines for Nick Fury, I learn them with one hand covering one eye so I can visualise the whole page in my head."

Jackson will next appear as Fury in Captain America: The Winter Soldier, which hits theatres in the U.S. on Friday (04Apr14).