This episode was proudly made possible by
the all-new 2015 Subaru Legacy. It’s not just a sedan, it’s a Subaru. Can you see everything on the screen without
moving your eyes? Look at me did you see that? Didn’t think so.[a] Howdy lookers, thanks for tuning into DNews,
I’m Trace. Eyes are little 1 inch diameter balls (2.54 cm) tucked in your head, and though
they’re magnificent, human eyes aren’t even CLOSE to the best in the animal kingdom. In
fact, your brain is tricking you into thinking your eye is seeing things that aren’t there
RIGHT NOW. We’ve all got blind spots that we can’t see, and huge sections of our vision
are just… wrong! Take a piece of paper with a dot and a plus
on it. Close one eye, hold the paper close to your face and look straight at the dot,
pulling it away slowly. Eventually, the plus should disappear! That’s your blind spot.
If you switch eyes, the dot should disappear. You might have to try it a couple of times.
To understand WHY this happens, we have to go inside the eye. If you could fly into the pupil and inside
the eyeball to look around you’d be floating in vitreous humor of the inner eye. It’s a
clear, gel-like material. On the walls of the eye, you’d see blood vessels streaming
everywhere, and spread across the back of the eye you’d see the rod and cone cells of
the retina. Rods are for low light, cones are for color and visual detail. If you got closer to the retina, you could
spot the macula right in the middle with only cone cells — that’s the only part of your
vision that you can see clearly. If you look at my face here, you can see it clearly, but
while still looking at my face pay attention to the walls around me, or my shirt. It’s
VERY difficult to comprehend the rest of your visual field. The macula is truly the only
point of visual clarity! From there, you could follow the nerves of
the retina, like following a bunch of extension cords to the wall. Eventually, you’d get to
the optic disk; a part of the eye with no rods or cones. That’s where the optic nerve
enters the eyeball! It’s kind of like where your eye plugs in. And it causes a blind spot.
There’s nothing there for your eye to perceive since there are no rod or cone cells! My eye doctor was nice enough to send me a
picture of the inside of my own eye. You can see the macula here, and the optic nerve here.
That is my point of clarity, and my blind spot! If it seems stupid to have a blind spot, you’re
right. Cephalapods don’t have one, because their optic nerves run BEHIND the retina rather
than in front of it. Think of it this way, cephalopods have their wiring inside the walls,
but because of an unfortunate evolutionary mutation, mammals didn’t and thus we all have
blind spots. The reason you don’t see this spot all the
time is because your brain fills it in. Try doing the dot and plus experiment with a piece
of colorful paper and your brain will fill it in with color. That’s your brain tricking
you into thinking your vision is perfect, when it’s really not. Silly brain, tricks
are for non-scientists. Blind spots are very important to be aware
of – especially when you’re driving! That’s why we wanna thank Subaru for making this
episode possible. And especially the all-new 2015 Subaru Legacy. Every sedan has its benefits,
but only one combines them all. It’s not just a sedan. It’s a Subaru. If you could have the eyes of another animal,
which would it be? Cats? Eagles? Cephalopods? Mantis Shrimp?!
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