BVP - Clinical Management of Oculomotility Dysfunction in Children - Week 9 Flashcards
Is the optokinetic nystagmus reflex slow or quick? Is it conjugate? When does it occur?
Slow, conjugate
When looking at objects passing across our field
What is the vestibulo-ocular reflex? Is it slow or quick? Is it conjugate?
Stabilises image on the retina when the head moves
Slow, conjugate
List four voluntary types of eye movements. Note if they are fast or slow, and if they are conjugate.
Fixation - inhibition of movement
Saccades
-fast, conjugate
Pursuit
-slow, conjugate
Vergence
-slow, disjunctive
What four extraocular muscles are supplied by CN3?
Superior rectus
Inferior rectus
Medial rectus
Inferior oblique
What extraocular muscle is supplied by CN6?
Lateral rectus
What extraocular muscle is supplied by CN4?
Superior oblique
List the primary action for each extraocular muscle.
Superior rectus - adduction
Inferior rectus - abduction
Medial rectus - up
Lateral rectus - down
Superior oblique - intorsion
Inferior oblique - extorsion
List the secondary actions (2) for four of the extraocular muscles.
Superior rectus - intorsion, adduction
Inferior rectus - extorsion, adduction
Superior oblique - down, abduction
Inferior oblique - up, abduction
Is the OKN reflex an advanced or primitive eye movement response?
Primitive
Concerning the OKN reflex in infants, what can be said of the symmetry between temporal-nasal response vs the nasal-temporal movement? What happens around 6 months of age? How does this relate to strabismus/amblyopia? Explain.
Temporal-nasal response greater than nasal-temporal movement
Becomes more symmetrical by 6 months
Strabismus/amblyopia delay this semmetry - possible to use this difference to screen?
Is the VOR advanced or primitive?
Primitive
Concerning VOR, what direction do the eyes move relative to the head’s movement?
Opposite
Concerning VOR, do infants have higher or lower gain compared to adults? What does this do? What happens to the gain with age? Why?
Have a higher gain - stabilises the image to ensure development of optimal acuity
Gain reduces with age as the other reflex systems sevelop to augment gaze
what are saccades like in infants vs adults (2)? What is the latency like in infants vs adults? What evolutionary purpose may this have? When is it thought to be developed by (age)?
Infant saccades are variable and inaccurate compared to adults
Latency higher in infants - 800ms infants vs 200ms adults
Made in response to maintain fixation of the mother
Developed by 6 to 12 months
List four subtypes of saccades.
Prosaccades
Regressive saccades
Antisaccades
Reflex saccades
What types of saccades do infants rely mor on to track vs smooth pursuit (note: not saccade subtypes)? What happens with age?
Depend on small saccades rather than smooth pursuit
With age, small saccades decrease and smooth tracking increases in between saccades
Are saccades attention dependent?
Yes
Is the devlopment of smooth pursuit in children symmetrical? Explain, giving age when mature (2).
Asymmetrical
Horizontal pursuit is mature by age 7
Vertical pursuit is mature by age 11
What aspect of oculomotor control us fully developed at birth? What happens following birth? What happens by age 1?
Virtually no aspect of oculomotor control is fully developed at birth but quickly develops following birth
Is close to adult levels at age 1
List four factors that limit oculomotor performance in neonates.
Attention
Motivation level of alertness
Distracton
Fatigue
What three things can the development of eye movements be affected by?
Stress/fatigue
Environmental factors
Genetic factors