Yes, just use 2 pieces of scatch paper you get from the proctor, the same size as the answer sheet and cover up everything above the line you're on with one, and everything below with another. I'd only be able to see the question I was working on. Too, I'd write the numbers of the questions on one of the pieces of scratch paper (1 to 60, for example, 1, 2, 3, 4, etc.) and after I answered, I'd put a checkmark next to that number and not allow going back, that question would be "through" and I'd have proof with my checkmark.

Another way would be to use your fingers as you start to work on a question to make sure you're working on "that" line only at that time and the rest of your hand/arm would naturally cover the rest of the test "below" so it wasn't so disturbing.

You could try starting at the bottom, last question, and work forward, up the page? That might be "difficult" enough to get your mind to have to focus better on what you're doing? Moving "up" the page is not "logical"/normal so it would be hard to be distracted by what was "beneath" because you'd be going the other direction.