Finally tonight, she lives in a world she can barely see, but she's doing something that few could ever dream, and inspiring people all over the country. So how strong do you have to be to change the... See More
Finally tonight, she lives in a world she can barely see, but she's doing something that few could ever dream, and inspiring people all over the country. So how strong do you have to be to change the world? As abc's steve osunsami shows, "america strong." Reporter: When charlotte brown runs down her lane with her pink pole vault and leaps into the sky, you hold your breath. She's just 15 years old, and she's learned to fly, but what's most amazing is -- she can't see. I can't really make up a -- make out a blur even. It just blends in for me. Reporter: She can't see the track or the fancy color of her pole vault, or the faces of the people in the stands. She's legally blind. So you have no idea what i really look like? Right. Reporter: Doctors don't know why, but she started losing her sight when she was just 16 weeks old. Several surgeries later, non of it helped. She took to the poll vault. This is what pole vaulting looks like to a sighted person, but is is what it looks like to charlotte. She said it's like looking down the inside of a little black straw and seeing a blurry light at the system. So she has a system. Her coach lays artificial turf next to her lane. She can see the difference between light and dark, and it helps her run straight. She counts her steps and then goes for it. Now get this. She's not just any pole vaulter, she's the best her high school has ever seen, and one of the best in the entire country. Clearing 11 feet six inches. When a kidomes in and talks to me about what they can't do, I point to the picture of charlotte up there and say, you tell her that. Reporter: It's not juch her coaches to think the world of her. Her parents. Don't ever tell her she can't do something. Reporter: And the letters that come from blind and visually impaired children from around the world. Dear charlotte, I wanted to say, I read a story about you, and it was awesome. Reporter: Today she's losing what little vision she has, it's getting worse, but she's not worried. She said an obstacle is just that. It can be moved, it can be jumped over. This story is not just about me. Everybody struggles with something. This was my struggle. This is not the worse thing that could ever happen. This just makes you stronger. "America strong" for sure.
This transcript has been automatically generated and may not be 100% accurate.