Reference: TC 3-04.93 Aeromedical Training for Flight Personnel (2009) - heloip

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Reference: TC 3-04.93 Aeromedical Training for Flight Personnel (2009)

Classes > Aeromedical

Crewmembers rely more on their vision than any other sense to orient themselves in flight. While vision is the most accurate and reliable sense, visual cues can be misleading and contribute to incidents within the flight environment. Aviation personnel must be aware of and know how to effectively compensate for physical deficiencies and self-imposed stressors as well as visual cue deficiencies and limitations.

Understanding basic anatomy and physiology of the eye enables crewmembers to use their eyes more effectively during flight. Light enters the eye and passes through the cornea, then the pupil in the center of the iris, then the lens then to the retina. The retnia has many tiny photoreceptor cells known as rods and cones. When light stimulates the retina, it produces a chemical change and then transmits it to the optic nerve then to the brain.

If you can remember the items in red above, you can understand the BASIC concept of how we see things.

Cornea - the clear protective cover for the eyes. The cornea is pressure and heat sensitive and will cause the eyes to blink if it feels pressure or heat.

Iris and Pupil - the iris controlls the size of the pupil and is colored. The pupil is in the center of the iris and controls the amount of light going in. When the light level is low, the pupil is large. When the light level is high, the pupil is small.

Lens - directs light to the retina. It adjust in length and size to bring the light to the correct place on the retina.

Retina - the light sensitive part of the eyes. All images are focused to this area and are picked up by Rods and Cones.

Rods and Cones - located in the retnia. Cones sense light and color and is used during the day. Rods sense light but no color and is used at night. Cones are near the center of focus and Rods are located outside of the focus area.

The impulses from the Rods and Cones are then transmitted to the brain by the Optic nerve. The brain then interprets the impulses and there you have it.... We see!

Watch the short video on Youtube for a review. How the eye works!

A deeper knowledge on Rods and Cones will be required for Night and Night Vision Goggle flying techniques.