Diagrammatic Representation of Eye Movements

Question 1

What is the method of assessing a strabismus?

Answer 1

Measure:
1. Basic deviation
2. Prism cover test in 9 positions
3. Head tilts:
a. Px will always tilt to lower eye -> lower eye needs to come up
b. 4th nerve palsy -> head tilt to opposite side of palsy
4. Near deviation
5. Versions & ductions
a. Cover test – alternate cover test in each of 9 positions of gaze
6. Characteristics of abnormal eye movements: uprifts, downdrifts, upshoots & downshoots, A & V patterns
Look at px as they come in the room

Question 2

How to assess a basic deviation?

Answer 2

• Prism cover test in primary position (PP)
  o Full correction of refractive error
  o Distance target (6m)
  o Fixation with usually fixing eye
  o Standard room lighting

Question 3

How to assess with a prism cover test (PCT) in 9 positions of gaze?

Answer 3

• Distance fixation
• Head moved until eyes take up extreme position of gaze
• Traditionally single prism used; held in front of paretic eye
• Near deviation then measured in PP
• Deviation on head tilting, if appropriate

Question 4

How to note deviation seen on PCT?

Answer 4

• E = Esophoria
• ET = Esotropia
• E’T = Near Esotropia
• E(T) = Intermittent Esotropia
• E(T) = Intermittent Esotropia (predominantly manifest)
• E(T) = Intermittent Esotropia (predominantly latent)
• X = Exophoria
• XT = Exotropia
• X’T = Near Exotropia
• X(T) = Intermittent Exotropia
• X(T) = Intermittent Exotropia (predominantly manifest)
• X(T) = Intermittent Exotropia (predominantly latent)
• HT = Hypertropia
• HYPO = Hypotropia

Question 5

Describe measurements of versions & ductions and how to note these?

Answer 5

• Versions are tested using a light as a target w/ both eyes open
• 6 version recordings for each eye are recorded corresponding to direction of principal action of the 6 EOMs of each eye
• Recorded using a 9 point scoring system:
• If XOP in primary then same at side then their motility is 0 (normal)
• Underaction:
  o -4 = no movement beyond midline (complete palsy)
  o -3 = 25 % normal movement
  o -2 = 50% normal movement
  o -1 = 75% normal movement (sclera just visible)
  o 0 = full excursion (sclera concealed by canthus)
• Overaction:
  o Horizontal overactions graded by amount of cornea covered by canthus
   +4 = half of cornea is buried
• Obliques Muscles:
  o Oblique overactions & underactions are graded by comparing heigh of inferior limbus of each eye

Question 6

Describe Jampolsky Gradings?

Answer 6

• Everything graded out of 4
  o Duane’s syndrome – cannot abduct from midline  -4
• All subjective  measure w/ prism bar
• Normal versions = 0
• Min U/action -1 Max U/action -4
• Min O/action +1 Max O/action +4
• Restriction/limitation can be hatched in
• Line emphasise A or V patterns
• Curve lines show Updrift or Downdrift

Question 7

What additional information should you note in diagrammatic representation of eye movements?

Answer 7

• Pupil anomalies
• Glove retraction
• Nystagmus
• Compensatory head posture
• Head thrusting