Saccade Test

15 February 2022
10 mins
Reading

What is the saccade test?

The saccade test measures the patient’s ability to accurately move the eyes from one designated focal point to another in a single, quick movement. The ability to accurately perform saccade testing assesses the patient’s central vestibular system. The random saccade paradigm has been established as the most useful for saccade testing; therefore, it is the random saccade test that is discussed in this paper.

 

Patient instructions

“You will see a green dot on the screen. Simply look at the dot. If the dot moves, follow it with your eyes only as quickly as you can. Try not to move your head.”

 

Normal saccade test results

A patient with the ability to perform a saccade test normally will produce a tracing in which the stimulus target and the eye tracings are virtually identical. The stimulus is represented by the yellow target line and the right and left eyes are represented by red and blue tracings, respectively. The responses for each saccade are represented on the accuracy, velocity and latency graphs by red dots for the right eye and blue dots for the left eye. Responses that are within threshold limits will fall in the white region and responses outside of threshold limits will fall in the grey shaded region.

Results overview for horizontal saccade test. Red and blue curves for right and left eye movements follow the yellow curve for target position smoothly and quickly. Graphs for latency, velocity, and accuracy indicate normal results, with results located in the white, normal regions, and not in the grey, abnormal regions.

Saccade test showing normal responses for horizontal targets

 

Abnormal saccade test results

Three parameters are taken into consideration for the analysis of the saccade test. They are:

  • Latency – how long it takes the patient’s eyes to find the target
  • Accuracy – whether the patient can move his eyes directly to the target without “overshooting” or “undershooting” the target (this is also referred to as precision)
  • Velocity - how fast the eyes are moving from point to point

Results overview for horizontal saccade test. Red and blue curves for right and left eye movements are jagged. Graphs for velocity and accuracy indicate abnormal results, with results located in the grey, abnormal regions.

Abnormal saccade test showing abnormalities in velocity, and accuracy

 

Conclusion

Saccade testing is an ocular test used to determine whether there is central pathology that is precluding accurate fixation of the eyes onto moving targets. Each of the saccade subtests can give anatomy- specific information about the patient’s central vestibular system. For a complete discussion of differential diagnosis using saccade testing, refer to:

Jacobson, GP, and Shepard, NT. Balance Functional Assessment and Management, 2nd Ed. San Diego; Plural Publishing, 2015

*NOTE: This is intended only as a guide, official diagnosis should be deferred to the patient’s physician.


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Interacoustics

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