Exam 2 Review

Question 1

What is the unique direction associated with each retinal image location?

Answer 1

Oculocentric visual direction

Question 2

What is oculocentric visual direction also known as?

Answer 2

Local sign

Question 3

What is the perceived direction of an object relative to the body?

Answer 3

Cyclopean direction

Question 4

What is another phrase for cyclopean direction?

Answer 4

Egocentric direction

Question 5

What 2 elements contribute to the perception of egocentric direction?

Answer 5

1. Oculocentric direction

2. Direction of gaze

Question 6

What 2 elements contribute to complete egocentric localization?

Answer 6

1. Egocentric direction

2. Distance (from stereopsis)

Question 7

What do corresponding points share?

Answer 7

Visual direction

Question 8

What is the locus of all points in space that image on corresponding retinal points?

Answer 8

Horopter

Question 9

What criterion does the IVD horopter use?

Answer 9

Identical visual direction

Question 10

What horopter is considered the “purest” way to measure the empirical horopter?

Answer 10

IVD horopter

Question 11

What type of task does the IVD horopter rely on?

Answer 11

Vernier task

Question 12

Where do the locus of points for the AFPP horopter appear in relation to the fixation target?

Answer 12

At the same stereoscopic distance

Parallel to the face like a picket fence

Question 13

What does AFPP stand for?

Answer 13

Apparent
Fronto
Parallel
Plane

Question 14

What is fixation disparity?

Answer 14

Convergence error relative to fixation

Question 15

Regarding over-convergence and under-convergence, what would eso and exo deviations be?

Answer 15

Over-convergence: eso deviation

Under-convergence: exo deviation

Question 16

What is located at the center of Panum’s fusional space?

Answer 16

Singleness horopter

Question 17

At what location are stereoacuity thresholds at their lowest?

Answer 17

Minimum stereoacuity threshold horopter

Question 18

Through what 2 points of each eye does the Veith-Muller circle run?

Answer 18

1. Fixation point

2. Nodal point

Question 19

What is a major assumption of the Veith-Muller circle?

Answer 19

Corresponding retinal points are distributed symmetrically

Question 20

What is a major reason for the difference between the theoretical and empirical horopter?

Answer 20

Differences in arrangement of corresponding retinal elements

Question 21

What is the angular deviation between the empirical horopter and the Veith-Muller circle known as?

Answer 21

Hering-Hillebrand deviation

Also known as the H deviation

Question 22

How does the empirical horopter change relative to the observer as fixation distance increases?

Answer 22

Horopter becomes more convex relative to the observer as fixation distance increases

Question 23

What is abathic distance?

Answer 23

Viewing distance at which the shape of the horopter is flat

Question 24

What planes are coincident at the abathic distance?

Answer 24

1. Objective plane

2. Apparent frontal plane

Question 25

What 2 points is the external longitudinal angle formed by?

Answer 25

1. Fixation point | 2. Secondary Point

Question 26

When R is not equal to 1, what will the empirical horopter exhibit?

Answer 26

Tilt | Towards one of the two eyes

Question 27

The analytical plot graphs the R-coefficient as a function of what?

Answer 27

Tangent of alpha-2

Question 28

The slope of the analytical plot is given by what value?

Answer 28

H-coefficient

Question 29

If H is not equal to 0, how does the empirical horopter appear relative to the Veith-Muller circle?

Answer 29

Either flatter or steeper in curvature

Question 30

What is aniseikonia?

Answer 30

Difference in size and/or shape of two retinal images

Question 31

What is anisometropia?

Answer 31

Difference in refractive error between the two eyes

Question 32

What is the most common cause of aniseikonia?

Answer 32

Anisometropia

Question 33

What is anisophoria?

Answer 33

Phoria that varies in different positions of gaze

Question 34

What would a meridional size lens of axis 90 do to an image?

Answer 34

Magnify image in the horizontal meridian

Question 35

How would the geometric effect impacting the right eye cause the gaze normal plane to appear?

Answer 35

Tilted away on the right side

Question 36

What would a meridional size lens of axis 180 do to an image?

Answer 36

Magnify image in the vertical meridian

Question 37

What kind of disparity would magnification in the vertical meridian of one eye create?

Answer 37

Vertical disparity

Question 38

What effect does vertical magnification over one eye produce?

Answer 38

Induced effect

Question 39

With the induced effect, which horopter rotates? Which horopter does not rotate?

Answer 39

AFFP horopter rotates | IVD horopter does not rotate

Question 40

What effect occurs when magnification of one eye is 5% greater than the other eye?

Answer 40

Geometric effect | Unopposed because the induced effect breaks down

Question 41

Will the induced effect and geometric effect ever cancel each other out? If so, when?

Answer 41

Yes | With small amounts of overall magnification

Question 42

Around what axis do the induced and geometric effects cause the gaze normal plane to appear to rotate?

Answer 42

Vertical axis

Question 43

Around what axis does the oblique effect cause the gaze normal plane to appear to rotate?

Answer 43

Horizontal axis

Question 44

What is declination?

Answer 44

Rotation of the vertical meridians toward the magnification meridian in oblique magnification

Question 45

What effect do Base Out prisms have on the gaze normal plane?

Answer 45

Plane appears to bend toward the observer

Question 46

What effect do Base In prisms have on the gaze normal plane?

Answer 46

Plane appears to bend away from the observer

Question 47

Which half of the empirical horopter exhibits a tilt away from the observer?

Answer 47

Top half tilts away

Question 48

Which half of the empirical horopter exhibits a tilt toward the observer?

Answer 48

Bottom half tilts toward