Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Human Performance + Limitations > The Eye And Vision - Chapter 6 > Flashcards

The Eye And Vision - Chapter 6 Flashcards

1
Q

Cornea is responsible for ______________% of the focussing of the eye

A

70% - 80%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The lens does what?

A

The final focussing of the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Iris controls the amount of…

A

Light entering the pupil.

This is controlled by the ANS.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

If the eye observes a close object, the pupil becomes:

A

Smaller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

If the eye observes an object at a distance, the pupil becomes:

A

Larger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The lens uses which muscles to make a final focus, and what is the process called?

A

Ciliary muscles and this is a process of accommodation.

This can be affected by age and fatigue.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

If the lens focuses on an object close to it, the lens…

A

Thickens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

If the lens focuses on a distant object, the lens…

A

Flattens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The image is __________ on the retina

A

Inverted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Light sensitive cells near the retina are called:

A

Cones and rods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Light sticking the rods and cones causes a _________________process which is then sent to the visual cortex via the optical nerve

A

Chemical, electrical process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Centre of the retina is called:

A

The Fovea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The fovea consists of:

A

Only cones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Vision through the rods is

A

Scotopic vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Vision through the cones is

A

Photopic vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

The C’s stand for?

A

Cones are Colour sensitive - Central Vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What do the rods see?

A

Black and white
Peripheral vision
Sensitive to low level light
Sensitive to movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

As environmental light diminishes, so does….

A

Colour vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The Fovea is…

A

Central part of retina
Consists only of cones
Has the acuity of 20/20
Central vision is found here

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Alphanumeric Information is….

A

Reading

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Alphanumeric information reading is limited to

A

The Foveal area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Visual field is defined as:

A

Central field + peripheral field = visual field

23
Q

20/20 is defined as:

A

You can see at 20ft what the normal person can see at 20 ft

24
Q

As your sight moves away from the Fovea, the effect is….

A

Rapid

25
Q

At 5’ from the fovea you can see only ________ what you can at 20/20

A

Half

26
Q

At 25’ away from the fovea you can see only _________ of 20/20

A

A tenth

27
Q

Acuity is affected by:

A

Angular distance from the fovea

28
Q

How long does it take the rods and cones to adapt to the light (from dark)

A

Cones - 10 seconds

Rods - 10 seconds

29
Q

How long does it take the rods and cones to adapt to the dark (from light)

A

Cones - 7 minutes

Rods - 30 minutes

30
Q

How is night vision affected by hypoxia, what stage is it in and at what altitude does it occur?

A

Hypoxia can cause a deterioration in night vision, it is in the indifferent stage and occurs at 5,000 ft

31
Q

Which works better for night vision, rods or cones?

A

Rods and they are more sensitive to low level light

32
Q

Night vision is affected by:

A 
Cabin altitude
Lack of vitamin A
Age
Mild Hypoxia
Smoking
33
Q

Stereopsis

A

Depth Perception (up to 200ft)

34
Q

Blind spots

A

No light sensitive cells, found at the optic nerve

35
Q

Empty field myopia

A

If the eyes are rested, the natural focus distance is 1-1.5m

36
Q

Photochromic sunglasses are _________ for flying

A

Prohibited

37
Q

Polarised sunglasses are ____________ in flying

A

Discouraged

38
Q

Eye movement is controlled by how many muscles?

A

6 extrocular muscles

39
Q

Long sightedness

A

Hypermetropia

40
Q

Short sightedness

A

Myopia

41
Q

For both long and short sightedness, the eyeballs are:

A

Misshaped

42
Q

To fix long sightedness (hypermetropia)

A

Convex lens

43
Q

To fix short sightedness (Myopia)

A

Concave lens

44
Q

In short sightedness, the light…

A

Doesn’t reach the back of the fovea

45
Q

In long sightedness, the light…

A

Makes an image behind the Fovea

46
Q

Presbyopia

A

Age affects eyesight

This is because the ciliary muscles weaken and the lens grows less flexible and so affects accommodation.

Causes a form of long sightedness.

47
Q

Astigmatism

A

Caused by a mis-shaped cornea

48
Q

Cataracts

A

Clouding of the lens

This can be cured by surgery

49
Q

Correcting Specs

A

Another, spare pair is to be carried at all times whilst flying where they’re easy to access.

50
Q

Glaucoma

A

Caused by a pressure rise of the liquid in the eye ball

If left untreated, can lead to blindness

Symptoms:

  • Acute pain in the eye
  • Blurred Vision
  • Sensitivity to high light levels
  • Visual field deterioration
  • Red discolouration of the eye
51
Q

Contact Lens’s

A

Can cause damage to the cornea with low humidity

May be dislodged by the rubbing of the eye, or an accidental knock

Bifocal contact lenses are prohibited

Must carry a pair of spare spectacles

52
Q

Colour blindness

A

Doesn’t affect acuity

Total colour blindness is rare

Caused by defects in the cones

Passed on through genes

53
Q

Monocular vision

A

A person with vision in only one eye cannot be accepted by EASA as fit to fly

Human Performance + Limitations (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions