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Human Performance

2.5.1 Vision

For visual flight rules (VFR) pilots, vision is the most important sense.

At the outermost point is the cornea, which

protects our eye. Behind it is the iris, which

determines how much light is allowed in. Next, we

have the lens, which can change shape and thus

focal length.

At the back, we have the macula and the blind spot. When you want to see

clearly, the image must be formed on the macula. Below the macula, where the

optic nerve exits, is a blind spot, but it has no practical significance if you have
two eyes.

2.5.1.1 The blind spot

Here is a figure where you can test whether you have a blind spot in your eye.

Try this: Cover or close your right eye. Focus on the star. Slowly move your head

toward the paper. At some point, the airplane will disappear.

You can also try this online: Find Your Blind Spot

The blind spot typically does not cause problems during flight, as the other eye

compensates and sees the object.

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 152