Side of the Eye

ZetaTalk wrote “look around the spot”, (of the coordinates). Also, looking out the side of your eye (something to do with retina reception) helps. Amazing. Just last night I was reading about improving nighttime vision. Here's a couple lines from a 1961 book called Living Like Indians: If you've lost sight of an object in dim light, look a little bit to its side. Often you can see it more clearly than if you look directly where you think it is. This army trick will help develop the rods in your eyes related to nighttime vision.

Offered by Mike.

This is not so much a "trick", it is a fact of how your eyeball is physically constructed. What should be patently obvious is that your vision is not the same in your entire field of view, all you need to do is look out of your eyeballs and notice that you cannot see something clearly at the side, but you can when you look directly at it. The most important thing to remember is that your eyes are not TV cameras and the operation principals are different in meaningfull ways. Much of what you attribute to the eye actually occurs in the brain, and in reality, distinguishing between the two is an arbitrary thing driven more by anatomy. The outermost peripheral vision is almost exclusively rods, with just enough cones to notice that there is some color there. The rods are ganged together with the circuitry in the retina which does three things.

1. the aggregate sensivivity is improved because you are adding the response together
2. there is a trememdous loss of detail
3. you optic nerve is smaller than your arm because not all points connect to your brain via a separate channel.

As you get closer to the center the ganging stops and the number of cone cells increases (color sensitive cells). In the most central region, called the fovea, where you have the greatest sensitivity to detail, there are almost no rods at all, only color sensors. At the very center of the fovea, there is a surprising lack of blue cones, so at the very center all you can see is red, yellow, orange, green (which "just happens" to be spectrally matched to the predominate color of the sun).

So the off axis trick means that you are using the ganged rods just off the central axis to see with. They are more sensitive to light in an absolute sense, can only see in B/W and are being ganged. So the bottom line is you can see objects that are dimmer, but you cannot see them with significant detail. Once you experience this, it is wierd to move you eye in and out and watch the objects "dissapear" and "reappear". If you go way off axis into your peripheral vision, you tend to lose things altogether because of the tremendous loss of detail. The trick does not "develop" over time as your eye is the way it is. What takes some time is to teach your *brain* to concentrate off to the side rather than do what it does 99.9999999% of the rest of your day. If you have never tried to do this before the temptation to move you gaze to the center is overwhelming, and when you yield, the object you are seeking simply dissapears. If you want to have the greatest sensitivity, one should avoid bright light essentially all day because only a few minutes of bright sun exposure has a dramatic effect on your night vision, hours later. Of course a much better alternative is a camera, either film or B/W CCD.

Offered by The Small Kahuna.