That's the problem with line of vision/interfering with play, when the ball was struck, Souza was about 3 yards to his left where the ball was going. If I was a keeper there is argument to say it was interfering with play and how far does the line of vision go are we talking peripheral vision too, as you might get distracted by that. Line of vision doesn't clear the law up neither does interfering with play. Although the goal would have been ruled out under the old Laws a simple, if you are offside you are offside approach would make things easier. On the flip side no offsides at all and just scrap Law 11 completely, it worked for (field) hockey.