Name of the Procedure:

Optokinetic Nystagmus Test, Bidirectional, Foveal or Peripheral Stimulation, with Recording

Summary

The Optokinetic Nystagmus (OKN) test is a non-invasive eye examination that measures involuntary eye movements elicited by moving visual stimuli. It specifically evaluates how well the eyes can follow objects moving in different directions (bidirectional) and can use central (foveal) or peripheral vision. The test results are recorded for further analysis.

Purpose

The OKN test is primarily used to assess the integrity of the visual and neurological systems, including the brain's ability to process visual movement. It helps diagnose conditions affecting eye movement control, vestibular function, and certain neurological disorders.

Indications

• Unusual eye movements
• Dizziness or balance issues
• Suspected neurological disorders such as multiple sclerosis
• Visual processing abnormalities
• Vestibular system dysfunction

Preparation

• No special preparations are usually required.
• Patients should inform their doctor about any medications they are taking.
• Glasses or contact lenses should be worn if prescribed.

Procedure Description

1. The patient sits comfortably in a chair.
2. A visual stimulus, typically a rotating drum or a series of moving stripes, is presented.
3. The patient is instructed to relax and naturally follow the moving patterns with their eyes.
4. Eye movements are recorded using specialized equipment, such as an eye-tracker or video camera.
5. The patterns may move left to right (horizontal) or up and down (vertical), and the test may involve both central and peripheral vision stimulation.

Duration

The test typically takes about 10-20 minutes.

Setting

The procedure is usually performed in a hospital's neurology or ophthalmology department or an outpatient clinic.

Personnel

• A neurologist or ophthalmologist
• A trained technician or nurse to assist with equipment

Risks and Complications

• The procedure is generally safe with minimal risks.
• Rarely, patients may experience mild dizziness or discomfort.

Benefits

• Provides valuable information about eye movement and neurological function.
• Non-invasive and quick.
• Helps in diagnosing and managing underlying conditions.

Recovery

• No specific recovery time is needed.
• Patients can resume normal activities immediately after the test.
• Any discomfort experienced during the test typically resolves quickly.

Alternatives

• Rotary Chair Test
• Electronystagmography (ENG)
• Magnetic Resonance Imaging (MRI) for comprehensive neurological assessment
• The alternatives may offer different insights but could be more invasive or less specific for certain conditions.

Patient Experience

• During the test, the patient may feel a bit strange following the moving patterns but should experience no pain.
• Any temporary dizziness should resolve shortly after the procedure.
• Comfort measures, like taking breaks between stimuli presentations, are provided if needed.