Week 6

Question 1

What are the 4 types of vergence found in maddox’s hierarchy?

Answer 1

1. Tonic
2. Proximal
3. Accommodative
4. Fusional

Question 2

What type of vergence is not apart of maddox’s hierarchy?

Answer 2

Voluntary vergence

Question 3

One’s anatomical eye position is found in what state?

Answer 3

Found in death, anesthesia, deprived environments

Question 4

Explain what tonic vergence does.

Answer 4

Brings eyes from divergent anatomical position or rest to convergent physiological position of rest

Question 5

Physiological position is found in what type of individuals?

Answer 5

Alert individuals in the absence of stimulus

Question 6

Balance of innervation to the EOMs puts the eyes in a neutral state. WIT?

Answer 6

Tonic vergence

Question 7

How do we determine tonic vergence?

Answer 7

Estimated by distance phoria on cover test

Question 8

Tonic vergence can be revealed when stimulation is under what conditions?

Answer 8

1. Reduced illumination
2. Eccentric stimulation
3. Physiological stress: Intoxication

Question 9

What is the most important componenet of vergence? What is it induced by?

Answer 9

Fusional Vergence

• induced by binocular disparity

Question 10

Fixation disparity is termed __? How is it measured?

Answer 10

An inaccuracy in vergence

Measured in minutes of arc (1’ = .029PD)

Question 11

What is the most common type of fixation disparity?

Answer 11

exo FD

Question 12

When the demand on vergence is large, the size of FD _____.

Answer 12

increases

Question 13

BI prism increases what type of FD?

Answer 13

Eso FD

Question 14

FD is used by what type of vergence system to improved vergence accuracy?

Answer 14

Closed-loop vergence system

Question 15

FD reveals vergence inaccuracy during ____ ____ while the eyes look at the same target

Answer 15

binocular fixation

Question 16

Binocular fixation of the same target is comprised of what vergence types for near?

Answer 16

1. Tonic
2. Proximal
3. Accommodative

Question 17

What are the methods to measure phoria?

Answer 17

1. CT
2. von Graffe
3. Maddox rod

Question 18

What is associated phoria?

Answer 18

the amount of prism it takes to neutralize one’s fixation disparity

Question 19

What is dissociated phoria?

Answer 19

The amount of prism it takes to neutralize one’s phoria (in CT)

Question 20

What is the average FD in a normal patient?

Answer 20

~ less than 5mins of arc (0.145pd)

Question 21

With increasing prism load, the magnitude of FD ___

Answer 21

increases

Question 22

BO prisms cause what type of FD?

Answer 22

cause Exo FD(eyes converge)

Question 23

Describe a Type 1 curve?

Answer 23

Equally susceptible to BI and BO prism loads

Question 24

Describe Type II curve?

Answer 24

Manage BO prism better than BI

Question 25

Describe Type III curve.

Answer 25

Manage BI prism better than BO

Question 26

Describe Type IV curve.

Answer 26

Can't manage any prism

Question 27

Prism adaptation acts to what?

Answer 27

reduce the stress in the vergence system

Question 28

Lenses can be used to affect FD by inducing what?

Answer 28

Accommodative vergence

Question 29

Prisms are used to affect FD by inducing what?

Answer 29

Disparity (fusional) vergence

Question 30

Minus lenses induce accommodation + increases accommodative vergence to result in what type of FD?

Answer 30

Eso-FD - causes eyes to diverge

Question 31

Plus lenses relax accommodation + decreases accommodative vergence resulting in what type of FD?

Answer 31

Exo - FD

Question 32

Symptomatic patients with an eso-FD can benefit from what type of lenses?

Answer 32

Plus lenses

Question 33

VT works better with eso or exo?

Answer 33

Exo | - easier to train convergence than divergence