strabismus in children

Question 1

what is ocular instability of infancy, when is it abnormal

Answer 1

• lateral ocular deviation, less than 15 degrees
• usually lasts 3 months
• if >15deg, or >3 months its abnormal

Question 2

what is pseudostrabismus

Answer 2

when the eye actually tracks normally, but because of the skull’s shape it looks like its misaligned

Question 3

strabismus - describe the light reflex test

Answer 3

• get child to look at a light
• if the reflection of the light off surface of cornea is symmetrical (central, slightly nasal), there is no squint
• if the reflection in one eye is too medial, they have an exotropia in that eye
• if the reflection in one eye is too lateral, they have an esotropia in that eye

Question 4

strabismus - management

• at GP level
• what’s actually done

Answer 4

if its ocular instability, review at 3 months then refer
otherwise refer to ophthalmology

what’s actually done - patching the eye. atropine penalisation. correct refractive error

Question 5

strabismus - cover test

- what defect does it test for, in which eye

Answer 5

manifest squint ie a tropia, in the uncovered eye

Question 6

strabismus - uncover test

- what defect does it detect, in which eye

Answer 6

latent squint ie a phoria, in the uncovered eye

Question 7

strabismus - cover test

- technique, interpretation

Answer 7

• get child to fix both eyes on an object
• cover the eye that you think is normal
• watch the uncovered eye. if it moves to refocus on the object, it’s a confirmed tropia (manifest squint) in the uncovered eye

Question 8

strabismus - uncover test

- technique, interpretation

Answer 8

• cover one eye for at least 5 seconds
• get child to focus on an object using the other eye
• take the cover off
• if the newly uncovered eye has to wander into fixation position, its a confirmed phoria (latent squint) in the uncovered eye

Question 9

strabismus - light reflex test

- what defect can it detect

Answer 9

a manifest squint ie a -tropia

Question 10

3 main causes of amblyopia

Answer 10

strabismus
anisometropia
visual deprivation (eg media opacity, ptosis)