Okay. >> Okay, do you wear glasses or contacts? >> I do. I'm an optician. >> Wait, can you just turn off my front forward-facing glasses? Or light from that glass on my ring. Did you wear glasses? >> I'm an optician. >> You're what? >> An optician. >> Oh, okay. >> Yeah. >> Very cool. My aunt was an optometrist. >> That's the same thing. >> Yeah. Okay, so you do wear glasses. >> Yeah, I have contacts on right now. >> Okay. Um, would you have any difficulty tracking something from a close distance back and forth? >> No, I feel very comfortable with that. >> Okay, very good. Wait for my partner. Okay, so what we're going to be using is my pen as a stimulus, okay? I'm going to have my thumb on the top of the pen just to better help you track it. What we're going to be doing is you're going to be tracking the very tip of the pen, okay? Do you understand? >> Yes, I do. >> All right, just have your feet together and arms down at your side. Okay, very good. Okay. So, you see the pen? Okay, and I'm going to be going side to side. What I want you to do is keep your head straight and only track it with your eyes, but I don't want you moving your head side to side. Do you understand? >> Yes, I do. >> All right.