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Aerospace Medical Education Division
AAM-400, P.O. Box 25082
Oklahoma City, OK 73125
How to Contact Us
To attend a physiology or survival class in Oklahoma City,
Oklahoma
Voice mail (405) 954-4837
Fax (405) 954-2305
To inquire about aviation physiology courses conducted at
military facilities:
(405) 954-4837
Other useful telephone numbers
• Aerospace Medical Certification Division
(405) 954-4821
• CAMI Library
(405) 954-4398
• Shipping Clerk
(405) 954-4831
Airman Education Personnel
Rogers V. Shaw, II (Team Leader)
Rogers.V.Shaw@faa.gov
J.R. Brown
Junior.Brown@faa.gov
Roger Storey
Roger.Storey@faa.gov
Larry Boshers
Larry.Boshers@faa.gov
Eric Simson
Eric.Simson@faa.gov
D.J. Demuth
Donald.Demuth@faa.gov
􀁮 􀁯
Vision is a pilot’s most important sense to obtain reference information during
flight. Most pilots are familiar with the optical aspects of the eye. Before we
start flying, we know whether we have normal uncorrected vision, whether we are
farsighted or nearsighted, or have other visual problems. Most of us who have prescription
lenses—contacts or eyeglasses—have learned to carry an extra set of glasses
with us when we fly, just as a backup. But, vision in flight is far more than a lesson
in optics. Seeing involves the transmission of light energy (images) from the exterior
surface of the cornea to the interior surface of the retina (inside the eye) and the
transference of these signals to the brain.
The Anatomy of the Eye
Light from an object enters the eye through the cornea and then continues through
the pupil.
The opening (dilation) and closing (constriction) of the pupil is controlled by the
iris, which is the colored part of the eye. The function of the pupil is similar to that
of the diaphragm of a photographic camera: to control the amount of light.
The lens is located behind the pupil and its function is to focus light on the surface
of the retina.
The retina is the inner layer of the eyeball that contains photosensitive cells called
rods and cones. The function of the retina is similar to that of the film in a photographic
camera: to record an image.
The cones are located in higher concentrations than rods in the central area of the
retina known as the macula, that measures about 4.5 mm in diameter. The exact
center of the macula has a very small depression called the fovea that contains cones
only. The cones are used for day or high-intensity light vision. They are involved
with central vision to detect detail, perceive color, and identify far-away objects.
The rods are located mainly in the periphery of the retina — an area that is about
10,000 times more sensitive to light than the fovea. Rods are used for low-light
intensity or night vision and are involved with peripheral vision to detect position
references including objects (fixed and moving) in shades of grey, but cannot be used
to detect detail or to perceive color.
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Light energy (an image) enters the eyes and is transformed by the cones and rods
into electrical signals that are carried by the optic nerve to the posterior area of the
brain (occipital lobes). This part of the brain interprets the electrical signals and creates
a mental image of the actual object that was seen by the person.
The Anatomical Blind Spot
The area where the optic nerve connects to the retina in the back of each eye is
known as the optic disk. There is a total absence of cones and rods in this area, and,
consequently, each eye is completely blind in this spot. Under normal binocular vision
conditions this is not a problem, because an object cannot be in the blind spot
of both eyes at the same time. On the other hand, where the field of vision of one eye
is obstructed by an object (windshield post), a visual target (another aircraft) could
fall in the blind spot of the other eye and remain undetected.
The Night Blind Spot
The “Night Blind Spot” appears under conditions of low ambient illumination
due to the absence of rods in the fovea, and involves an area 5 to 10 degrees wide
in the center of the visual field. Therefore, if an object is viewed directly at night, it
may go undetected or it may fade away after initial detection due to the night blind
spot.
• The Fovea
The fovea is the small depression located in the exact center of the macula that
contains a high concentration of cones but no rods, and this is where our vision is
　
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