Manual: Eyesight and Visual Illusions Flashcards
Each eye is connected to the brain by an ……. nerve.
optic
To look at a near object, the eyes have to turn slightly (inward/outward).
inward
The natural focal point for the eyes when resting is about (1 to 2 meters/ 20 meters/200 meters/infinity). This is referred to as ….. ….. myopia.
1 to 2 meters, empty field
A person with only one eye (will/will not) have protection from the blind spot.
will not
A person with two eyes (does/does not) have blind spots. The second eye (does/does not) provide protection.
does, does
Focusing both eyes on the one object is called ……. vision, and it (helps/ does not help) with depth perception.
binocular, helps
The transparent cap over the lens of each eye is called the ……. .
cornea
The cornea can be protected by the ….. closing over it.
eyelid
The colored membrane between the cornea and the lens is called the ….. , and it contains a small, round aperture called the ….. which (can/cannot) change in size.
iris, pupil, can
in bright light, the pupil will e (small/wide); in dim conditions, the pupil will be (small/wide).
small, wide
The part of the eye that can change shape and does most of the focusing of the lights rays is the …. . The greater its curvature, the (greater/lesser) the focusing.
lens, greater
The ability of an eye to change its focus point is called ………. .
accommodation
The lens should focus the incoming light rays on the light-sensitive layer at the back of the eye, known as the …… .
retina
The central section of the retina consists mainly of …….. cells which (are/are not) sensitive to color, (are/are not) sensitive to small details, (are/are not) sensitive to distant objects, and are most effective in (daylight/darkness).
cones, are, are, are, daylight.
The peripheral, outer region of the retina consists mainly of …… cells which (are/are not) sensitive to color, and (are/are not) sensitive to small details, and (are/ are not) sensitive to distant objects and are most effective in (daylight/darkness).
rod, are not, are not, are not, both daylight and darkness.
The blind spot in each eye is where the …. nerve leaves the retina.
optic
the ability to see clearly and sharply is called visual …… .
acuity
Visual acuity (is/is not) diminished by fatigue or alcohol.
is
In strong sunlight or glary conditions you should wear …….. .
sunglasses
Depth perception when landing is (easier/more difficult) in hazy or foggy conditions.
more difficult
On approach in hazy conditions, the runway way be (closer/further away) than what is appears to be, often causing pilots to flare too (early/late).
closer, late
Men are (more/less) likely then woman to have some form of color-blindness.
more
The eyes take about .. minutes to adapt to darkness. The most effective retinal cells in darkness are the (rods/cones) which are used for (peripheral/central) vision.
30 minutes, rods, peripheral
Bright light in the cockpit at night can destroy light adaption (immediately/ after about 5 minutes), and it then takes about .. minutes to re-establish full light adaption.
immediately, 30 minutes.
When scanning for aircraft by day, you should use your (central/peripheral) vision.
central
When scanning for aircraft by night, you should use your (central/peripheral) vision.
peripheral
The resting eye sources at about ….. meters; this is known as e…… f…… m…… , so we (do/do not) have to concentrate on focusing on distant aircraft.
1 to 2 meters, empty field myopia, do
The visual illusion of a single station-ary light at night appearing to move is called ……. .
autokinesis
Sloping cloud banks by day or town lights at night appearing to move is called …….. .
can
The normal approach path to a runway sloping upwards will appear to be too (steep/shallow), causing a tendency for an inexperienced pilot to fly too (high/low) on slope.
steep/low
The normal approach path to a runway sloping downwards will appear to be too (steep/shallow), causing a tendency for an inexperienced pilot to fly too (high/low) on slope.
shallow, high
An especially wide runway will appear to be (closer/further) away than it really is during the late stages of an approach, causing a tendency for an inexperienced pilot to flare too (high/low).
closer, high
An especially narrow runway will appear to be (closer/further away) than it really is during that late stages of an approach, causing a tendency for an inexperienced pilot to flare too (high/low).
further away, low
During a night approach, the apparent gap between the runway edge lights is increasing. The aeroplane is flying to an aiming point (before/at/beyond) the normal aiming point.
beyond
During a night approach, the apparent gap between the runway edge lights is decreasing. The aeroplane is flying to an aiming point (before/at/beyond) the normal aiming point.
before
It is (good/poor) airman ship to use a v……. a….. s…… i…… at night.
good, visual approach slope indicator.
An approach at night to a well-lit runway, but with no lights to be see is called a …… - ….. approach.
black-hole
The lack of features near a runway, say during a back-hole approach or in a white-out snow conditions , make depth and slow perception (more/less) difficult.
more
The term myopia refers to (long/short) sightedness.
short
A short-sighted eye focuses the light rays (too much/ not enough).
too much
A long-sighted eye focuses the light rays (too much/ not enough).
not enough
Short-sightedness is called ……. ; long-sightedness is called …….. or ……… .
myopia, hyperopia or hypermetropia
Reading becomes more difficult with age because the eyes become more (long-/short-)sighted, known as ………. . It causes diminished (near/far) vision, and is often corrected by using (full-/half-)glasses.
long-sighted, presbyopia, near, half-glasses
Faulty curvature of the lens is called …….. .
astigmatism
If glasses are required for flying, you should carry (one/two/three) pairs.
two
What do Rods do?
Rods are responsible for vision at low light levels (scotopic vision). They do not mediate color vision, and have a low spatial acuity.
What do Cones do?
Cones are active at higher light levels (photopic vision), are capable of color vision and are responsible for high spatial acuity. The central fovea is populated exclusively by cones. There are 3 types of cones which we will refer to as the short-wavelength sensitive cones, the middle-wavelength sensitive cones and the long-wavelength sensitive cones or S-cone, M-cones, and L-cones for short.
