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The Hess Screen Test



The Hess Screen is an ophthalmological diagnostic device used to assess the mobility of the eyeball. In a healthy person, the eyeballs move symmetrically and simultaneously. Unfortunately, sometimes it happens that the muscles responsible for these movements are overactive or inactive in one eye, which results in paresis.

The Hess Screen Test is primarily used to recognize and control disorders such as strabismus and double vision. It is helpful in diagnosing the so-called nystagmus, i.e. uncontrolled, rapid eye movements. The Hess screen is also used to diagnose the so-called gaze paralysis, which may be a symptom of neurological diseases, as well as injuries of the central nervous system, such as multiple sclerosis, aneurysms, or Lyme disease.

Conditions that require Hess Screen testing:

  • strabismus (especially in children),
  • impaired mobility of one eyeball,
  • the patient incorrectly locates objects around him,
  • follow-up after some ophthalmological operations.


How is the Hess Screen Test performed?

We examine the mobility of the patient’s eyeballs using the coordinometry method on the Hess Screen. This test does not require any special preparation on the part of the patient.

The patient sits comfortably in front of the Hess Screen grid at a distance of 0.5 to 1 m. They put on red and green glasses, which cause the vision of the right and left eyes to be separated. The patient holds a laser pointer or a flashlight with which they point to dots appearing on the screen. The test result is then further analysed and recorded on two diagrams.

The Hess Screen Test is non-invasive and painless. 

It takes about 15-20 min.