06. The Eye and Vision Flashcards
The Eye and Vision
What are the 5 human senses
- SIGHT
- HEARING
- SMELL
- TOUCH
- TASTE
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The Eye and Vision
Which sense is the most significant to the brain
SIGHT
1
The Eye and Vision
The eye is filled with 2 fluids that help maintain the spherical shape. What is the name of the 2 fluids
- AQUEOUS HUMOUR
- VITREOUS HUMOUR
2
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The Eye and Vision
AQUEOUS or VITREOUS humour occupies the space in front of the lens
AQUEOUS HUMOUR
The Eye and Vision
AQUEOUS or VITREOUS humour occupies the space behind the lens
VITREOUS HUMOUR
The Eye and Vision
The translucent ____ allows light to enter the eye and fall onto the lens
CORNEA
2
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The Eye and Vision
Which part of the eye contracts and expands the size of the aperture in response to light levels
IRIS
2
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The Eye and Vision
The focusing process, in which the contraction and relaxation of the ciliary muscle takes place, thus changing the focal length of the lens, is known as what
ACCOMMODATION
The Eye and Vision
The ____ is situated behind the iris and is flexible so that it can be stretched to change chape for fine control of focus
IRIS
2
The Eye and Vision
Light is focused by the lens on to the light sensitive membrane know as the ____, where it is converted into electrical impulses
The cornea helps focus light onto which part of the eye
RETINA
2
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The Eye and Vision
The most sensitive part of the retina, densley packed with cones
FOVEA
2
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The Eye and Vision
The retina converts lgiht into electrical impulses which are transmited to what part of the brain
BRAIN STEM
2
The Eye and Vision
The electrical pulses received by the brain stem are routed to which part of the brain, which is where teh information from both eyes is interpreted
VISUAL CORTEX
2
The Eye and Vision
The optic nerve has no photoreceptors where it attaches into the eye. This creates a what
BLIND SPOT
2
The Eye and Vision
What is the name of the small ring of muscles that attach around the lens and adjust the shape
CILIARY MUSCLES
The Eye and Vision
Most light refraction takes place in which part of the eye
CORNEA
The Eye and Vision
- When looking at distance objects, the lens will become FATTER or FLATTER
- When looking at near by objects, the lens will become FATTER or FLATTER
- FLATTER
- FATTER
3
The Eye and Vision
RODS or CONES are the most sensitive receptor to light
RODS
REMEMBER
* Cones = Colour
* Rods work in low light conditions but are not sensitive to colour
* Cones oly react to bright light and are coloud sensitive
4
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The Eye and Vision
RODS or CONES are the most sensitive receptor to colour
CONES
REMEMBER
* Cones = Colour
* Rods work in low light conditions but are not sensitive to colour
* Cones oly react to bright light and are coloud sensitive
4
115
The Eye and Vision
Rods and cones are known by what name
PHOTORECEPTORS
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The Eye and Vision
Cones are concentrated at the point where most light naturally falls. This is the central are of the retina known by what name
FOVEA
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The Eye and Vision
Cones detect colour vision, referred to as ‘light seeing’. This is known as what
PHOTOPIC VISION
4
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The Eye and Vision
Rods detect various shades of light and dark and are not colour sensitive. They provide what is known as what vision, which means ‘dark seeing’
SCOTOPIC VISION
4
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The Eye and Vision
In regards to visual acuity, if you are said to have 20/20 vision, how is this actually deciphered
You can see at 20 ft what a normal person can see at 20 ft
- Visual acuity is now expressed in meters
- 20ft = 6m so you would be said ot have 6/6 vision
5
The Eye and Vision
If your visual acuity ratio is expressed as greater than 1 i.e. you are said to have 6/4 vision, what does this mean
BETTER THAN NORMAL
You can see at 6m what a normal person can see at 4m
5
The Eye and Vision
Regardless of an individuals inherent visual acuity, the clarify of vision will be affected by which of the following’
[ ] WHAT YOU RECENTLY ATE OR DRANK
[ ] AMOUNT OF FLIGHT AVAILABLE
[ ] SIZE AND CONTOURS OF AN OBJECT
[ ] HOW TALL YOU ARE
[ ] DISTANCE OF AN OBJECT FROM VIEWER
[ ] HOW COLD IT IS
[ ] CONTRAST OF AN OBJECT WITH SURROUNDINGS
[ ] RELATIVE MOTION OF A MOVING OBJECT
[ ] CLARITY OF THE ATMOSPHERE
[ ] THE SEASON OF THE YEAR
[ ] WHAT YOU RECENTLY ATE OR DRANK
[X] AMOUNT OF FLIGHT AVAILABLE
[X] SIZE AND CONTOURS OF AN OBJECT
[ ] HOW TALL YOU ARE
[X] DISTANCE OF AN OBJECT FROM VIEWER
[ ] HOW COLD IT IS
[X] CONTRAST OF AN OBJECT WITH SURROUNDINGS
[X] RELATIVE MOTION OF A MOVING OBJECT
[X] CLARITY OF THE ATMOSPHERE
[ ] THE SEASON OF THE YEAR
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The Eye and Vision
The entire area of space which can be seen at any one time, which is about 120° left and right, and 150° up and down is known as what
VISUAL FIELD
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The Eye and Vision
- The up and down visual field of the eye is approximately how many degrees (°)
- The left and right visual field of the eye is approximately how many degrees (°)
- 150°
- 120°
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The Eye and Vision
There is an overlapping area of 60° of the visual field where both eyes used together is possible. This is known as what sort of vision
BINOCULAR VISION
REMEMBER
* BI = 2 = both eyes
* MONO = 1 = single eye
5
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The Eye and Vision
The visual field and acuity of a single eye is known as what sort of vision
MONOCULAR
REMEMBER
* BI = 2 = both eyes
* MONO = 1 = single eye
5
124
The Eye and Vision
Why is it important to frequently change your focus of attention when looking out of the cockpit window
BLIND SPOT
avoid potential threat coinciding with the blind spot
- Within the binocular area each eye has an anatomical blind spot
- This is where the optic nerve leaves the eyeball
- In normal binocular vision conditions, this is not a prpoblem since an object cannot fall on both eyes blindspots at the same time
- If vision to one eye is blocked i.e. windshield post, an aircraft could fall into the blind spot of one eye
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The Eye and Vision
Which vision cannot distinguish detail but is very sensitive to detecting movement
PERIPHERAL VISION
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The Eye and Vision
- The area of cone vision in teh fovea is sometimes known by what name
- The visual acutity is the greatest and is approximately how many degrees (°) wide
- CENTRAL VISION
- 1°
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The Eye and Vision
Short range depth perception is achieved at ranges less than ____ by the ____ effect of binocular vision
- 1 METER
- STEROSCOPIC
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The Eye and Vision
“distant objects move relative to each other as a result of head movements”
This is a definition of what
PARALLAX
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The Eye and Vision
“Converging parallels such as railway lines, roads and the edges of runways give the pilot what”
This is a definition of what
PERSPECTIVE
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The Eye and Vision
“Distance objects are smaller”
This is a definition of what
RELATIVE SIZE
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The Eye and Vision
“objects in front of other objets must be closer”
This is a definition of what
OVERLAPPING CONTOURS
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The Eye and Vision
“The scattering of light makes distance objects norally appear bluer due to the colour of the sky, thought a red sky will lend a rosy shade to objects for the same reason”
This is a definition of what
AERIAL PERSPECTIVE
aka atmospheric perspective
6
The Eye and Vision
What is the most common colour blindness
RED/GREEN
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The Eye and Vision
- Colour blindness occurs in approximately what percentage of men
- Colour blindness occurs in approximately what percentage of women
- 7%
- 0.1%
- Colour blindness is more likely in men
6
The Eye and Vision
What are the 2 ways in which the eye will adapat to reducing amounts of light
- DILATE PUPIL
- CHEMICAL REACTION IN RODS AND CONES
- Pupil will dilate to allow more light in
- Chemical reaction is in the rods and cones as they start to adapt to lower light levels
7
The Eye and Vision
CONES or RODS adapt fastest to a reducing amount of light
RONES
7
The Eye and Vision
- Cones take approximately ____min to adapt to reduced light levels
- Rods take approximately ____min to adapt to reduced light levels
- 7 MIN
- 30 MIN
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The Eye and Vision
Adaption of the photoreceptor cells i.e. the rods and cones, can cope with light levels how many times weaker than full daylight
150,000 TIMES
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The Eye and Vision
Smokers are at a greater risk of what ailment at altitude which effects night vision
HYPOXIA
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