Strabismus and movement disorders

Question 1

Types of strabismus (3)

Answer 1

• eso(older children, often intermitten)/exo(children, can be due to hypermetropia)/hyper/hypotropic
• manifest (always there)/latent (only present when eye closed)
• non-paralytic (size of deviation constant) or paralytic.

Question 2

potential long-term complication of strabismus

Answer 2

strabismic amblyopia (lazy eye); can’t be corrected w. glasses.

Question 3

Causes of strabismus (7)

Answer 3

• congenital: at birth/<6mo
• myopia, hypermetropia, astigmatism: develops >2yrs
• syndromes: down’s/noonan’s
• assoc. w. prematurity and FHx
• muscle weakness: paralytic
• hydrocephalus, brain tumour, injury
• retinoblastoma

Question 4

Features of IIIrd nerve palsy (4)

Answer 4

down and out
fixed, dilated pupil
ptosis
proptosis

Question 5

Features and causes of VIth nerve palsy (6)

Answer 5

unable to abduct eye
diplopia in horizontal plane

causes:

• tumour raising ICP>compression
• skull base trauma
• MS
• vascular

Question 6

Features of IVth nerve palsy (3)

Answer 6

diplopia
patient may tilt head to compensate: ocular torticollis
patient can’t turn eye down and in.

Question 7

VIIth nerve palsy features and Mx (6)

Answer 7

Bell's phenomenon: eye rolls upwards when lid closed
can be disturbed leading to drying of eyes
Rx:
-tapes eyes shut
-liquid eyedrops
if this fails:
-tarsorrhaphy
-botox into levator palpebrae
-gold weights in upper eyelid.

Question 8

Hx and Ex features of a squint (8)

Answer 8

commonly:

• diplopia
• eye misalignment
• amblyopia

also:

• visual confusion
• abnormal eye movements
• asthenopia: tired, painful eyes
• intermittent closure of one eye
• CN palsies

Question 9

Screening tests for strabismus (4)

Answer 9

Cover test:

• eyes fixate on point then one is covered
• if uncovered eye moves, this one has squint
• moves inwards=exotropia, outwards=esotropia
• requires co-operation (hard with children) and fixation (hard if strabismal ambylopia)

Simultaneous prism and cover test: works out angle of strabismus

Uncover test:

• if cover test -ve, uncover covered eye
• if uncovered eye moves there may be latent strabismus
• alternate prism cover test works out angle of latent strabismus

Corneal reflection:

• reflection from bright light falls centrally and symmetrically on each cornea if there is no squint
• asymmetrical if there is squint

Question 10

Mx of strabismus (3)

Answer 10

glasses, vision therapy and surgery (3 Os)

optical

• cyclopentolate given to assess refractive state
• glasses correct refractive state

Orthoptic:
-patching for amblyopia

Operation:

• shortening/lengthening of extra-ocular eye muscles
• botox injections into muscles