Asklemmy

So, here's a lesson from the flight physiology chapter of the private pilot syllabus:

Your vision is a lot worse than you think it is. You probably conceptualize your eye as similar to a digital camera, there's a lens that focuses light on a sensor made up of an array of light sensitive cells, and that the edge of that array is as densely packed as the center. This is the case for a camera, but not for your eye.

Each of your eyes has over 30 million photoreceptors called rods and cones.

Rod cells come in one variety and are only really good for detecting presence or absence of light. They work well, or can work well, in very dim light, and they form the basis of your night vision. This is why in very dim conditions you might experience your vision in black and white.

Cone cells are less sensitive to light requiring relatively bright light to function, and come in three varieties that respond the strongest to low, middle and high wavelengths of light, what we know as red, green and blue. By comparing the relative intensities of these wavelengths, we can derive color vision. They don't work well in low light conditions.

The sensor array in the back of your eye that contains these photosensitive cells, called the retina, is sparsely populated toward the edges and doesn't have very good resolution. Try reading this sentence looking at it through the corner of your eye. It gets denser and denser, and the ratio of cones to rods increases, until you reach a tiny pit in the very center called the fovea.

This is difficult to put into words but unless you've been blind since birth you'll understand what I mean: You use your whole retina to "see." You use your fovea to "look." The detailed center of your vision, the spot where you are "looking" is drawn from the fovea through the center of the lens out into the world. When you are looking at something, you are pointing your fovea(s) at it.

There are no rod cells in your fovea, only cones. So you have very high resolution color day vision, but next to no night vision, with your fovea.

This is why things like dim stars in the night sky can be more easily seen with your peripheral vision than your central vision. Your central vision does not have the cells to see well in the dark. It's not in the anatomy.

We teach this to pilots because distant lights the pilot is using to navigate by, avoiding collisions with obstacles or other aircraft, might be dim enough that the night adjusted eye can't actually see it with the center vision but can with peripheral vision.

The same chapter teaches about the "hole" through which the optic nerve passes and how that blind spot is capable of hiding something like another airplane from you, which is why you look around and don't just stare out the windshield. It's not often a problem because most of the time one eye can see into the other's blind spot, but it's useful to know that about your vision.

Each cell will detect some light, undergo a chemical process that fires an adjacent neuron, and then take a very brief moment to reset to be ready to do it again. Each cell is doing this independently, so your eyes don't have a "frame rate" the way a camera does, but a flickering light begins to look continuous to humans at a rate of about 18 cycles per second and no flicker can be detected somewhere around 40.

Your occipital lobe takes in this choppy inconsistent resolution broken up mess of visual information passed to it via your optic nerves, does some RTX DLSS 4k HDR10 shit to it and outputs the continuous and smooth color 3D picture you consciousness experiences as "vision."

AND THEN ON TOP OF THAT your brain does optical everything recognition. You can look at millions of different objects - the letters of the alphabet, tools, toys, people, individual people's faces, leaves, flowers, creatures, stars, planets, moons, your own hands, and recognize what they are with astonishing speed and accuracy.

It's what scientists call the hellawhack shiznit that happens inside your brizzle.