Binocular Vision

Question 1

Why test binocular vision?

Answer 1

if 2 eyes not working together efficiently=symptoms

Question 2

What happens if only one eye is working?

Answer 2

strabismus or amblyopia, reduced acuity, no 3D, career considerations

Question 3

Why do we do BV testing?

Answer 3

to determine if child is using both eyes (motor and sensory)

Question 4

What are BV tests?

Answer 4

alignment, motilities, tests of motor fusion, tests of sensory fusion

Question 5

What are tests of motor fusion?

Answer 5

NPC, vergences

Question 6

What are tests of sensory fusion?

Answer 6

stereopsis, worth 4 dot

Question 7

T/F infants are esotropic

Answer 7

false, may look esotropic because of lid anatomy but are not

Question 8

T/F infants have poor control of convergence in the first few weeks of life

Answer 8

true

Question 9

How many infants are orthophoric?

Answer 9

1/2

Question 10

How many infants are exotropic/ C or I?

Answer 10

1/3

Question 11

When should you expect orthophoria and convergence from an infant?

Answer 11

3 months

Question 12

What is the purpose of a cover test?

Answer 12

to determine ocular alignment in different positions of gaze, frequency and magnitude

Question 13

What are normal values for cover test?

Answer 13

distance: ortho- 3XP
near: ortho-6XP’

Question 14

What does the unilateral cover test detect?

Answer 14

tropia

Question 15

What does the alternate cover test detect?

Answer 15

phoria

Question 16

What does the prism alternate cover test measure?

Answer 16

movement with prism

Question 17

What prism neutralizes Eso, Exo, Hyper, Hypo?

Answer 17

BO, BI, BD, BU

Question 18

Which distance is harder for infant cover test… distance or near?

Answer 18

distance, may only get near info

Question 19

What should the target be for an infant cover test?

Answer 19

your finger

Question 20

What is angle kappa?

Answer 20

angle between the line of sight (fixation to fovea) and the pupillary axis

Question 21

What is the pupillary axis?

Answer 21

center of pupil, tangential to cornea

Question 22

How do you measure angle kappa?

Answer 22

look at corneal light reflex monocularly with light at 50 cm and midline

Question 23

What is a + angle kappa?

Answer 23

reflex nasal=fovea displaced temporally

Question 24

What is a - angle kappa?

Answer 24

reflex temporal= fovea displaced nasally

Question 25

Most people have a mild ____ kappa

Answer 25

positive, fovea five degrees temporal to center of posterior pole

Question 26

What is the hirschberg test?

Answer 26

looking at corneal reflex binocularly to determine if a deviation exists, estimates angle kappa

Question 27

How do you do the hirschberg test?

Answer 27

light at 50 cm midline, reflex should be symmetrical OD, OS and roughly 0.5 mm nasal

Question 28

What is 1mm in prism diopters?

Answer 28

22 prism diopters

Question 29

Displacement nasal (+)=

Answer 29

exo

Question 30

Displacement temporal (-)=

Answer 30

eso

Question 31

What is the Krimsky test?

Answer 31

essentially hirschberg with prism, still observing corneal reflex with light at 50 cm midline

Question 32

What is fixating v nonfixating eye in krimsky?

Answer 32

check for differences and not modified/reverse krimsky for non-fixating eye ????

Question 33

What is the bruckner test?

Answer 33

using direct ophthalmoscope, adjust focus so patient's face is clear, 1 m in front of paitent

Question 34

What do you look at with bruckner test?

Answer 34

hirschberg (check for strabismus) and size/color of pupils and brightness of fundus reflex

Question 35

Which eye is brighter in a bruckner test?

Answer 35

strabismic, because of the macular pigment

Question 36

What can the size, color and brightness of the pupil tell you?

Answer 36

strabismus, anisometropia, media opacities

Question 37

T/F preschool and school aged kids should be able to get a cover test and distance and near

Answer 37

true

Question 38

What do you have to record with strabismus?

Answer 38

test used, which eye, frequency, direction, distance/near?

Question 39

How do you record the frequency of a strabismus turn?

Answer 39

POTT= percentage of time troped, constant or intermittent, exotropia scale

Question 40

How long do you observe before testing and using the exotropia scale?

Answer 40

30 seconds

Question 41

What is the procedure to use before looking at the exotropia scale?

Answer 41

cover OD 10 sec, cover OS 10 sec, cover OD 10 sec, distance and near

Question 42

What numbers on the exotropia scale depict poor control?

Answer 42

3-5

Question 43

Which numbers on the exotropia scale depict good control?

Answer 43

0-2

Question 44

What is a 5 on the exotropia scale?

Answer 44

constant exotropia

Question 45

What is a 4 on the exotropia scale?

Answer 45

exotropia > 50% of exam before dissociation

Question 46

What is a 3 on the exotropia scale?

Answer 46

exotropia <50% of exam before dissociation

Question 47

What is a 2 on the exotropia scale?

Answer 47

no exotropia unless dissociated, recovers in > 5 sec

Question 48

What is a 1 on the exotropia scale?

Answer 48

no exotropia unless dissociated, recovers in 1-5 seconds

Question 49

What is a 0 on the exotropia scale?

Answer 49

no exotropia unless dissociated, recovers in <1 second (phoria)