the ocular movement test.docx

8/13/2019 the ocular movement test.docx

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CHAPTER II

LITERATURE REVIEW

Testing the smooth pursuit system in each direction of gaze first assesses the extent of

ocular movement. The subject is instructed to follow a spotlight from the primary position to

the limits of each position of gaze in turn. The head must be kept stationary. Details which

should be observed when testing ocular movements are:3

1. The extent of ocular movement in each eye2. The quality of the movement, if it is steadily maintained or if catch up saccades occur3. Whether fixation can be maintained when the limit of movement is reached or if there is

end-point nystagmus or even gaze-evoked nystagmus

4. The effect of repeated testing of both smooth pursuit and saccadic movement-this isespecially important in patients with a history suggestive of myasthenia gravis

5. Any discomfort on movement, which can occur with mechanical restriction or aninflammatory condition

6. Whether the movement ceases gradually or suddenly7. A difference between version and duction8. Change in the position of the eyelids, for example lid-lag seen in thyroid eye disease9. Change in the position of the globe, for example globe retraction sometimes accompanies

mechanical restriction

10.A change in palpebral fisure size, which can be seen, for example, in Duanes retractionsyndrome

11.The presence of nystagmus and its directionThe information recorded must include: 3

1. Whether movement is full, limited, or excessive2. The grade of abnormality, usually -4 to +43. Direction of the abnormality (this may be related to the muscle affected, if knoen, e.g.

underaction of right superior oblique).

4. Any associated signs, for example globe, fissure, or lid changes, or the presence ofnystagmus).

Ductions and Versions

Ductions test monocular movements and are examined with one eye occluded, forcing

fixation to the eye being examined. Ductions evaluate the ability for the eye to move into


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extreme fields of gaze. This is a scale of 0 to -4, with -1 limitation meaning slight limitation

and -4 indicating severe limitation with inability of the eye to move past midline. This scale

can be used to measure horizontal and vertical ductions.4 Ductions should be tested with each

eye whenever limitation of movement is seen or suspected, moving the target to the limit of

gaze. It is normal for duction to be slightly greater than versions, especially on lateral gaze. In

neurogenic palsies, movement will improve on ductions but no significant improvement

occurs if a mechanical restriction is present.3

Figure 1. Ductions are monocular eye movements (A) normal Abduction; (B) -1 limitation to abduction; (C) -2

limitation to abduction; (D) -3 limitation to abduction; (E) -4 limitation to abduction. This scheme is used to

quantitate limitation of duction movements and can be used for abduction aor vertical ductions as well.

Versions test binocular eye movements and show how well the eyes move together in

synchrony. Versions will detect subtle imbalance of eye movements and oblique muscle

dysfunction missed on ductions. Evaluation of versions should include eye movements

through the nine cardinal position of gaze: from primary position to straight right, straight

left, straight up, straight down, up to the right, up to the left, down to the right, and down to

the left. Abnormal versions can be noted on a scale of +4 to -4 with 0 indicating normal and

+4 indicating maximum overaction, whereas -4 indicates severe underaction.4

Limitation of movement is usually graded on a scale of -1 to -4; -4 indicates that there

is no movement beyond the midline; -3 indicates that 25% movement remains; -2, 50%; and -1, 75%. If the eye cannot reach the midline, the extent of limitation should be recorded as -5


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or higher if necessary. Duction should be compared with version and any difference between

them should be recorded.3

Overcation is graded from +1 to +4. These movements can be more difficult to gauge,

but using the inferior oblique as an exampke, +1 would indicate excessive elevation only in

the field of main action and +4 would mean the maximum amount of elevation anatomically

possible. Grades +3 anf +4 of overaction usually indicate an updrift is present on horizonal

movement, whereas +2 overaction indicates that the eye has to be in an elevated position

before excessive movement occurs.3

Figure 2. Versions are binocular eye movements: dextroversion, rightgaze; levoversion, leftgaze; superversion,

upgaze; infraversion, downgaze.

Figure 3. Versions showing overaction of the oblique muscles: upper drawing, right inferior olique overaction

+3; lower drawing, right superior oblique overaction +3. (B) Version showing underaction of the oblique

muscles: Upper drawing, -3 underaction of the right inferior oblique; lower drawing, -3 underaction of the riht

superior oblique.


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CHAPTER III

CONCLUSION

An ocular motility screening evaluation includes the range and symmetry of motion of

both eyes together (versions) and each eye individually (ductions). The information recorded

must include:

1. Whether movement is full, limited, or excessive2. The grade of abnormality, usually -4 to +43. Direction of the abnormality (this may be related to the muscle affected, if knoen, e.g.

underaction of right superior oblique).

4. Any associated signs, for example globe, fissure, or lid changes, or the presence ofnystagmus).

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