Is it normal to see these strange things?

My mother's CATS used to get that shit all the time.

I'm not exactly sure how detailed/etc your visions of dots/lines/colors are, but this happens to me too only it's mostly shadowy shapes that move around and morph, and sometimes look really weird. They used to scare me when I was a kid, until I realized they were only that weird when I really paid attention to them. Now, I've been told they're called "floaters", basically bubbles in the surface of the eye or somesuch, though it can also happen when I look at a bright light for too long (ie looking at a bulb while turning on a lamp - the bulbs are *bright*) and the afterimage has to fade. Either way, it's just eyes being their fluid selves, though if it starts to get too intense, you may want to go back to the doctor.