Vergence

Question 1

maddox’s 5 components of vergence are:

Answer 1

• tonic
• proximal
• voluntary
• accommodative
• disparity

Question 2

the response in the absence of stimulus is called _____ vergence

Answer 2

tonic

Question 3

tonic vergence is about ____ prism diopters of convergence

Answer 3

2-4 prism diopters of convergence

Question 4

_____ convergence is driven by perception of nearness of an object (less than 3 meters)

Answer 4

proximal convergence

Question 5

_____ vergence is driven by voluntary effort (on purpose)

Answer 5

voluntary

Question 6

____ vergence is driven by accommodation and an important component of the near response

Answer 6

accommodative vergence

Question 7

AC/A ratio is

Answer 7

accommodation convergence per unit of accommodation (in prism diopters / diopter)

Question 8

______ AC/A ratio assumes a perfect response to accommodation

Answer 8

stimulus

Question 9

______ AC/A ratio is more accurate

Answer 9

response

Question 10

_____ AC/A ratio is usually 10% less than the ______ AC/A ratio

Answer 10

response is 10% less than stimulus

Question 11

accommodative convergence can provide over _____ of the required convergence at near

Answer 11

a half

Question 12

high AC/A ratio means

Answer 12

AC can provide much more

-eso at near

Question 13

low AC/A ratio means

Answer 13

AC can provide much less
-exo at near
(more common)

Question 14

AC/A ratio is responsible for patient’s ____ ______

Answer 14

near phoria

Question 15

______ vergence is driven by binocular disparity, and has closed-loop negative feedback control
(also called fusion or reflex)

Answer 15

disparity

Question 16

uncrossed retinal disparity requires _____ for fusion

Answer 16

divergence

Question 17

crossed retinal disparity requires _____ for fusion

Answer 17

convergence

Question 18

object images on the foveal have ____ disparity

Answer 18

0

Question 19

_____ is responsible for the patient’s near phoria

Answer 19

AC/A ratio

Question 20

_____ is responsible for the patient’s distance phoria

Answer 20

tonic vergence

Question 21

phasic controller element is the:

Answer 21

fast component of disparity vergence

Question 22

tonic adaptive controller element is the:

Answer 22

slow component for disparity vergence

Question 23

problems with what can lead to asthenopia (eye strain)?

Answer 23

tonic adaptive controller element (slow component to disparity vergence)

Question 24

negative fusional vergence uses ___ prism and tests ____

Answer 24

base in (BI) to test divergence

Question 25

positive fusional vergence uses ___ prism and tests _____

Answer 25

base out (BO) to test convergence

Question 26

adding ___ prism stimulates accommodation therefore accommodation must relax

Answer 26

BO (convergence)

Question 27

adding ___ prism inhibits accommodation therefore accommodation must stimulate

Answer 27

BI (divergence)

Question 28

what does the blur point represent?

Answer 28

the fusional vergence without the effects of accommodation

Question 29

what kind of fusional vergence amplitudes are associated with less asthenopia?

Answer 29

larger fusional vergences

Question 30

why are larger fusional vergences associated with less asthenopia?

Answer 30

they can compensate for larger phorias

Question 31

the break point is a measure of

Answer 31

the amount of fusional vergence that is not independent of accommodation

Question 32

the total demand on the fusional vergence system is the:

Answer 32

phoria plus the compensating vergence

Question 33

interval between 0 and the blue point (or break if no blur occurs) = ______ vergence

Answer 33

relative

Question 34

interval between the phoria and the blue point in the opposite direction = ______ vergence

Answer 34

fusional

Question 35

blur point is from _____ vergence only

Answer 35

fusional vergence only | vergence independent of accommodation

Question 36

what does accommodation do after blur?

Answer 36

after blur, accommodation contributes to the vergence response

Question 37

when can you analyze using Morgan's data?

Answer 37

if no or low phoria (1EP-1XP at far) or (0-6XP at near)

Question 38

PFV compensates for:

Answer 38

XP

Question 39

NFV compensates for:

Answer 39

EP

Question 40

right infravergence compensates for

Answer 40

right hyperphoria

Question 41

Sheard's criterion states that

Answer 41

relative vergence reserve needs to be at least twice the demand

Question 42

Sheard's criterion is a good predictor of symptoms in

Answer 42

moderate to high XP

Question 43

Percival's criterion is a better predictor of symptoms in cases of

Answer 43

esophoria | moderate

Question 44

Percival's criterion states

Answer 44

the lower magnitude vergence should be at least 1/2 of the higher magnitude vergence

Question 45

using prism as a treatment option causes:

Answer 45

decreases the vergence demand

Question 46

what is the net result from using prism as a treatment option

Answer 46

smaller phoria and larger compensating ranges

Question 47

what prism would be used for esophoria

Answer 47

base out prism

Question 48

what prism would be used for exophoria

Answer 48

base in prism

Question 49

addition lenses at near would be a useful treatment option for:

Answer 49

esophoria at near

Question 50

addition lenses at near can cause:

Answer 50

decreases accommodative demand which then decreases accommodative-convergence