Am I going blind, or just being observant?

[LikeMyCloset]

So last night after I turned out my lights I realized that I could see a dim light (through the a/c vent from the next room) but only using my peripheral vision. When I looked at it dead on I couldn't see the light at all until I got up and moved closer to it, but whenever I looked away from it, I could see it great. Do we naturally have more of an ability to see light/dark with our peripheral vision or have I done something to my vision that needs attention? I realize this is a bit of random question, but thought someone might know....

[Remy]

Your eyes has 2 kinds of cells: cone cells and rod cells. At the back of each of your eyeballs is a small gap where sensory neurons and whatnot connect your eyes to your brain. That's called the retina. And around that retina is an area called the fovea.

With all that said, cone cells are primarily for detecting colours, while rod cells detect shape, motion, and brightness. These cells are in all parts of your eyes, but at the fovea is where you focus your vision, and the cone cells are more prominent there. Outside of the fovea is your peripheral vision (things you see on the borders of your vision even when you're not directly looking at them), and the rod cells are more dominant in these areas than cone cells. What all this means is that, you will have an easier time detecting the brightness of the dim light in your peripheral vision, because there are more rod cells there.

I personally get this from staring up at the stars too. It's quite cool.

[Chandra]

You have found your blind spot: http://en.wikipedia.org/wiki/Blind_spot_(vision) And not to worry, everyone has one. You are not going blind.

I found mine in the same way, by looking away from a little point of light in the dark, and suddenly not being able to see it. You usually can't find your blind spot during full daylight, because your eye automatically "fills in" the missing information for you.