Accommodation and Vergence

Question 1

What is binocular vision (BV)?

Answer 1

Two eyes working together as a functional pair to produce a single image by using sensory and motor components

Question 2

What kind of symptoms can BV cause?

Answer 2

Diplopia, confusion, headaches, asthenopia. It can also lead to unwanted behaviours and can signal serious health issues.

Question 3

Three key binocular concepts?

Answer 3

1. Sensory and motor components to be working together
2. Vergence and accommodation to be working together
3. The brain to provide a single and clear image whenever you direct your fixation

Question 4

What is a corresponding retinal point?

Answer 4

The two fovea’s are corresponding retinal points

Question 5

What is retinal disparity?

Answer 5

Angular substence of deviation of
an image from corresponding points. Corresponding points have zero disparity. Disparate images fall on non-corresponding points/

Question 6

What is crossed and uncrossed disparity?

Answer 6

Crossed - object appears closer than fixation
Un-crossed - object appears further from fixation

Question 7

What are the types of vergence? (4)

Answer 7

fusional vergence
Accommodative vergence
Proximal vergence
Tonic vergence

Question 8

What are the types of accommodation? (4)

Answer 8

Reflex accommodation
Vergence accommodation
Proximal accommodation
Tonic accommodation

Question 9

What makes up the near triad?

Answer 9

Vergence, accommodation and pupillary constriction

Question 10

What is positive and negative accommodation?

Answer 10

When both eyes are working together to provide binocular single vision (to see clearly)
Positive responses and lag of accommodation. Negative responses are lead of accommodation

Question 11

AC/A ratio?

Answer 11

Measures the accommodative convergence to accommodation ratio