Binocular Vision 2 - Week 2

Question 1

Define Vergence

Answer 1

simultaneous movement of both eyes in opposite directions to obtain or maintain single binocular vision

Question 2

What stimulates vergence eye movements?

Answer 2

displacement or movement of a target toward or away from the subject

Question 3

What anatomical factors can influence vergence?

Answer 3

• size of globe
• shape of globe
• position of EOM insertion

Question 4

What neurological factors can influence vergence?

Answer 4

Any lesions affecting innervation of cranial nerves III, IV, VI

Question 5

What general factors can influence vergence?

Answer 5

• fatigue
• alcohol
• tobacco
• medications
• prism in glasses
• FAT PM *

Question 6

Name 6 types of vergence responses

Answer 6

• fusional/disparity
• proximal awareness
• accommodation
• tonic
• voluntary (convergence)
• vergence adaptation

Question 7

Describe vergence/eye position in tonic conditions

Answer 7

Slightly eso posture

Question 8

What features of vergence function can we measure clincally? and how can we test these?

Answer 8

Vergence posture - heterophoria
Vergence ranges - PRC, NRC
Vergence facility - BI, BO challenge flippers
NPC - combined skill test

Question 9

What tests can we use to measure vergence posture?

Answer 9

Prentice Card
Von Graefe
Maddox Rod/modified thorington technique
Cover test
Maddow wing

Question 10

Are PRC and NRC measured with a phoropter or in free space?

Answer 10

Can be either

Question 11

What base power prism flippers do we use when testing vergence facility?

Answer 11

12 base out and 3 base in