Heterophoria

Question 1

Normal Binocular Vision:

Answer 1

both eyes simultaneously cooperating with their bifoveal fixation to give a single perception of the object

Question 2

Sensory fusion

Answer 2

integation of similar images at the cortex

This is what the brain does with the information

Question 3

Motor fusion:

Answer 3

Motor alignment to sustain binocular vision

suppression –> scotoma

Question 4

Motor fusion tries to ____ of the 2 images

Answer 4

eliminate disparities

Question 5

It tries to make images from each eye _____ to make one image

Answer 5

FUSE as best as possible

Question 6

Motor fusion _____ to produce 1 image

Answer 6

needs vergences

Question 7

Convergence tries to maintain binocular vision by ensuring images are on ___________ so there is no disparity between the images

Answer 7

corresponding retinal areas of each eye

I.E. NPC is the closest distance where the eyes can converge and maintain binocular vision

Question 8

Cover-Uncover Test (Unilateral Cover Test) helps to differentiate:

Answer 8

• presence of a deviation
• laterality/which eye (unilateral or alternating)
• frequency of the deviation (constant or intermittent)

Question 9

Alternating Cover Test is used to determine

Answer 9

• direction of phoria or tropia

- magnitude (size) of the deviation

Question 10

Which Cover Test is performed first?

Answer 10

Cover-Uncover Test (Unilateral Cover Test)

Question 11

Do you perform cover test at near, distance or both?

Answer 11

Both

Question 12

A phoria is seen on _____ because fusion is broken

Answer 12

alternate cover test

Question 13

An alternating tropia means

Answer 13

either eye can fixate on the target

Question 14

_____ is a tendency of the eyes to deviate when fusion is blocked.

Answer 14

Heterophoria (phoria)

Question 15

When there is binocular vision and fusion on a target, both eyes will be

Answer 15

aligned on the target

Question 16

Binocular Single Vision is when

Answer 16

the visual axes of both eyes intersect and fixate on the target (as long as there is fusion)

Question 17

Visual axes is from

Answer 17

the fovea to the point of fixation

Question 18

Even though a phoria only occurs when fusion is broken, there could be ______ in the binocular vision with a heterophoria

Answer 18

abnormalities

Question 19

True/False: A patient may appear aligned, but there could be underlining abnormalities in the ability to keep fusion.

Answer 19

True

Question 20

Symptons associated with a heterophoria may occur when/if

Answer 20

fusional amplitudes are not enough

Question 21

Give examples of Heterophoric abnormalities:

Answer 21

• Convergence Insufficiency
• Convergence excess
• Divergence insufficiency
• Divergence excess

Question 22

How can a phoria be identified?

Answer 22

Phorias can be identified and measured during a cover test or with a maddox rod

Question 23

What is a maddox rod used to measure?

Answer 23

Horizontal and Vertical phorias at distance and near

Question 24

What does the maddox rod do?

Answer 24

dissociates the eyes

Question 25

Maddox rods can also be ___

Answer 25

white