Performing a standard eye examination in neurology

EyeSeeCam Examination

EyeSeeCam is a wearable head-mounted device allowing objective measurement of eye movements. Eye movement disorders, even if subtle, can be detected, which helps improve the sensitivity and specificity of the clinical diagnosis. Supranuclear vertical saccade palsy, which can develop into complete gaze palsy in the course of the disease, is an eye movement disorder that can be detected in more than 95% of all patients with Niemann-Pick type C (NP-C). By careful examination it can often be recognized before other neurological symptoms become apparent. Even though detectable by performing a bedside examination of eye movement, in clinical practice supranuclear saccade palsy is often missed in the differential diagnosis of NP-C, especially in the early course of the disease and younger patient populations with NP-C.

A study validating EyeSeeCam for detection of progressive supranuclear palsy (PSP) showed that the gaze-driven video camera setup allowed detection of impaired saccade velocity and amplitude (Marx et al. 2012). The method is also useful to evaluate disease progression through repeated examinations.

Using EyeSeeCam to examine NP-C patients revealed that these patients not only show macroscopically detectable slow saccades but also different saccade patterns including staircase and pursuit-like movements when eliciting vertical saccades. In addition, horizontal saccades are also slower than in healthy volunteers (Bremova et al., unpublished).

In contrast to other methods such as scleral search-coil technique, EyeSeeCam is a non-invasive, mobile device, which includes a battery of vestibular and ocular motor tests. This makes it a useful tool for detection of eye movement disorders, especially for disorders such as slowing of saccades, which can be difficult to detect using bedside examinations alone.

  1. System calibration. The patient is asked to follow the moving target
  2. The cooperation of the patient can be tracked real-time by observing the video (left upper corner) and lines indicating the position of the eye (right side)
  3. Normal calibration cross-like array
  4. Vertical saccade examination. Patient is asked to follow the jumping target.
  5. Real-time video of saccade examination. Red line indicates vertical eye movement, blue line indicates horizontal eye movement
  6. Horizontal saccade examination
  7. Normal saccade data. Black line indicates the stimulus, blue line indicates the eyes, green dot the saccade onset, red dot the saccade end
  8. Smooth pursuit examination. Patient is asked to follow the moving target
  9. Smooth pursuit data. Note the high vertical and horizontal gain (eye velocity/stimulus velocity) in the lower left corner
  10. Examination of gaze holding function for vertical gaze (underlying anatomical structure: Interstitial nucleus of Cajal (INC) and for horizontal gaze (Nucleus praepositus hypoglossi (NPH)
  11. Optokinetic nystagmus. Patient is first asked to shortly fixate the white dot presented on the screen
  12. Horizontal optokinetic stimulation. Patient is asked to stare to the center of the black-white pattern and not to follow the stripes
  13. Vertical optokinetic stimulation
  14. Optokinetic data with normal peak slow phase velocity in all directions
  15. Examination of the vestibulo-ocular reflex (VOR). Patient is asked to fix the white dot presented on the screen. Examiner moves abruptly the head approximately 10x to the left and 10x to the right in a pseudorandomized way
  16. Real-time VOR examination, as presented by the video-oculographic software. The blue line represents the head movement, the black line the eye movement (right side of the screen)
  17. VOR data. The normal gain (eye velocity/head velocity, 1.0±0.2) indicates the normal function of the VOR system

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