Extraocular Motilities (EOM)
PURPOSE To assess the patient’s ability to perform conjugate eye movements．
EQUIPMENT
·Penlight
SET-UP
·The patient removes his spectacles．
·The examiner holds the penlight．
STEP-BY-STEP PROCEDURE
1．Perform the Hirschberg procedure as described earlier in the chapter．
2．Instruct the patient to follow the light with his eyes without moving his head．Ask him to tell you if he ever sees the light double，or become two, or if he feels any pain，strain，or discomfort while moving his eyes．
3．Start with the penlight directly in front of the patient．This is called the “primary position．”
4．Move the light to the eight additional positions shown in Figure 2-9．The order in which the positions are tested is not important．It is critical, however, to test gaze in all nine positions．In this step you are tracing the pattern of a large letter H bisected by a vertical line as shown in Figure 2-9．
5．Throughout step 4, point the light at the patient’s eyes as they follow the penlight．Look for changes in the relative positions of the corneal reflections, as in the Hirschberg test．Do not move the penlight too far．At a test distance of 30 to 40 cm, a movement of the light 30 to 40 cm from the primary position will detect ocular deviations of about 40°．This is sufficient to uncover weak extraocular muscles．
6．Throughout the procedure observe：
a．the smoothness of movement
b．the accuracy of following the penlight
c．the extent of movement
7．If the patient reports diplopia in any position of gaze，perform the Muscle Field with Red Lens，Ductions，and Saccades procedures described in Chapter 8．
RECORDING
·If the patient follows the light smoothly to all positions of gaze with both eyes and never reports diplopia(double vision)or discomfort, write SAFE or FESA．These letters stand for：S：Smooth，A：Accurate，F：Full．E：Extensive．
·If the patient shows any problem，record only the letters that apply and describe the problem，for example：
jerky，unsteady，nystagmoid
failure to follow into(give the location)
restricted，lagging，noncomitant．
·Identify the direction(s) of gaze that result in diplopia and/or discomfort．
·If only one eye is the abnormal one, be sure to identify it．
EXAMPLES
·EOM：SAFE
·EOM：diplopia on -right gaze，OD lagging
·EOM：FESA，OD pain on left gaze
EXPECTED FINDINGS
·FESA．
·No pain or diplopia．
·At the extreme limits of a healthy patient’s gaze it is normal to observe a low amplitude nystagmus，a so-called end-point nystagmus．
