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This article is a continuation of the earlier articles regarding Driving Under the Influence and the tests and requrements that police need before making an arrest.  I left off the previous article on the Nystagmus tests and the things an officer will be looking for when conducting these tests.


I left off wiht step Six

here is step 7.

Check the right and left eye for the “Distinct and Sustained Nystagmus at Maximum Deviation clue”

If the jerkiness is distinct and sustained that is one clue.

Once again the position the stimulas approximately 12-15 inches in front of the subjects nose and slightly above eye level. 

Move the sitmulas off to the right side (checking the subjects left eye) untle the eyes have gone as far as possible

Hold the stimulas steady at that position for a minumum of fourt (4) seconds, and carefully watch eye. 

Then move the stimulas back across the subjects face all the way out to the left side.  (subjects right eye)

Hold the stimulas steady steady and carefully watch they eye. 

If the person is impaired, they eye is likely to exhibit definite, distinct and sustained jerking when hield at maximum deviation for a minumum of four seconds.  In order to “count” this clue as evidence of impairment, the nystagmus must be distinct and sustained for a minimum of four seconds. 

each eyes should be checked twice for this clue. 


The jerking of the eyes that occurs when they are brought out as far to the side as possible.  Most unimpared people people exhibit Endpoint Nystagmus.


This type of Nystagmus may occur if a persons eyes are held at maximum deviation for more than 30 seconds. 

Step 8 Onset of Nystagmus prior to 45 degrees. 

The stimulus is a positioned approximately 12-15 inches from the subjects nose and slightly above eye level.  It is necessary to move the stimulas slowly to identify the point at which the eye begins to jerk. 

Start moving the stimulus towards the right side (left eye) at a speed that would take approximtely 4 seconds for the stimulus to reach the edge of the subjects shoulder. 

As you slowly move the stimulus, watch the eye carefully for any sign of jerking.  When you see the jerking begin, immediately stop moving the stimulus and hold it steady at that posiiton. 

With the stimulus held steady look at the eye and verify that the jerking is continuing.  If the jerking is not evident with the stimulus held steady you have not located the point of onset.  Therefore, resume moving the stimulus slowly toward the side until you notice the jerking begin.

When you locate the point of onset Nystagmus you must determine whether it is prior to 45 degrees. 

Veriy that some white is still moving in the corner of the eye.

Examine the aglignment between the stimulus and the edge of the subjects shoulder.

Repeat the process of the subjects right eye. 

Each eye should be checked twice for this clue.

Step 9 total the clues

Maximum number of clues possible for each eye: 3

Total Maximum number of clues possible for both eyes 6. 

Step 10.  Check for vertical Nystagmus

Postion the stimulus horizontally about 12-15 inches in front of the subjects nose. 

Instruct the subject to hold the head still, and follow the eobject with the eyes only. 

Raise the object until the subjects eyes are elevated as far as possible

Hold for a minimum of four seconds. 

Watch closely  for evidence of they eyes jerking upward. 

For VGN to be recorded.  It must be distinct and sustained for a minimum of four seconds at maximum elevation. 

VGN may be present in subjects under the influence of high doses of alcohol for that individual or some other drugs. 

This article will be continued  

Gerald Schwab, Jr.


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