I see something in my eye?

I can't see it when i look in the mirror.But i see it cause its in my eye.Its like a little hair Cause it moves when i look left,it will slowly go to left vise versa.Is that dirt or something?I read Almanac Global for kids and i saw that if you look in the sun,you will have cataract.I remember i looked at the sun thrice but i searched the cataract looks like and i saw that a eye with cataract have white spot i looked in the mirror but i saw nothing.I see i color black hair.It changes its direction when im in a bright place it becomes white.What am i going to do?BTW i always scratch my eye cause its itchy.But now i don't scratch it but i scratch it sometime when i woke up cause i'm not in my self yet.Any idea?By the way the hair or something is moving freely like a web or something.