Baltimore Ravens running back Alex Collins acknowledged that he's wearing a dark visor on his helmet to help his long-time migraine battle.

"I would get a little slight headache here and there, but for the most part, from wearing a dark visor, it does a good job," Collins said. "I have it in practice, and I am able to run full speed out there."

Collins, the Ravens' leading rusher this season, got approval from the league during the preseason to wear the visor.

Alex Collins got approval from the league during the preseason to wear the visor. Jeff Hanisch/USA TODAY Sports

He still deals with the severe headaches occasionally. He couldn't speak to reporters after a game earlier this month because of a migraine.

"I have had this migraine problem for a while, like since high school," Collins said. "Just throwing up before the games and having to play through it ... I am used to playing with them and dealing with it."

Collins ranks ninth in the NFL with 825 yards rushing and has scored five touchdowns. He ran for a career-high 120 yards in Sunday night's 39-38 loss to the Pittsburgh Steelers.

How dark is the visor?

"It's like playing in the shade all the time," Collins said. "What really activates the migraines is just ... When everyone looks at the sun, you have to put your hand over your eyes to block the sun, and you have to squint your eyebrows. For most people, that doesn't bother them -- they're just blocking the sun. But for me, that strain is what stimulates the migraine." Collins added, "Just from straining my eyes trying to focus on something, and playing out there at that speed, just straining and trying so hard to block out the sun is when the migraines really come in. But, when I'm able to play with a relaxed face out there, just reading my keys and doing what I need to be doing without that strain on my eyes, then the migraines don't happen."