Lots of Grainyness in my Vision (especially in the dark)?!

Hello. So for pretty much as long as i can remember, i have been seeing grainy in the dark. kind of like static from a T.V. set. I get the occasional sparkly spot, too. I used to think nothing of it, but now i am unsure if it is abnormal, as i can't seem to find any posts or anything like that that completely relate to my problem. I do frequently stare at my computer screen, but as i said, it's been happening since i was a little kid. I do not use drugs, nor have i ever. Also when i close my eyes, i do not see completely pitch black- i will see the usual grainyness, as well as some patches of random blobs (it's hard to explain) moving around. This is sometimes visible in the day. When i look up at a clear sky, i can see tons of floaters and sometimes the grainyness. Also, when i look at something dark in color, such as a blackboard, i can sometimes see grainyness. I am 15 years old. SIDE NOTE: I don't know if this relates at all, but i was recently told by my doctor i have panic disorder or anxiety. Could this be in relation to that? (i don't know if i've had it my whole life, but i've always been a little paranoid, and have had frequent nightmares as a child.

Please help as best you can.
Thank you very much.