Longitudinal Studies and Eye-Movement-Based Treatments of Infantile Nystagmus Syndrome: Estimated and Measured Therapeutic Improvements in Three Complex Cases

J Binocul Vis Ocul Motil. Oct-Dec 2018;68(4):122-133. doi: 10.1080/2576117X.2018.1522917. Epub 2018 Oct 17.

Abstract

Introduction and purpose: To demonstrate the utility of using eye-movement data to reveal the diagnostic characteristics of infantile nystagmus syndrome (INS), determine treatment, and both estimate and document therapeutic improvements in three patients with well-developed foveation periods, fairly broad, lateral gaze "nulls," head turns, strabismus, and complex, multiplanar nystagmus.

Patients and methods: Infrared reflection, magnetic search coil, and high-speed digital video systems were used to record the eye movements of INS patients, pre- and post-Kestenbaum null-point correction surgery (horizontal or vertical). Data were analyzed and estimations made, using the eXpanded Nystagmus Acuity Function (NAFX) that is part of the OMtools toolbox for MATLAB.

Results: In all three subjects (S1-S3), both peak NAFX and longest foveation domain (LFD) improved from their pre-Kestenbaum values. S1: 0.700-0.745 (6.4%) and 25-34° (36%), respectively. S2: 0.445-0.633 (42.4%) and >40° to >50° (10%), respectively. S3: 0.250-0.300 (20%) and 13° to ≫18° (see text), respectively.

Conclusions: S1: Even at the high ends of the pre-therapy NAFX and LFD spectra, INS foveation (and therefore, visual-function) improvements may be adequate to justify nystagmus surgery and provide clinical improvements beneficial to the patient. S2: INS foveation improvements in the vertical plane are equal to those originally estimated using the horizontal data in prior patients. S3: Two apparent NAFX peaks can be converted into a very broad peak by surgery based on the preferred lower peak.

Keywords: Infantile nystagmus syndrome; acuity; diagnosis; eye movements; foveation; surgery.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Adult
  • Electronystagmography
  • Eye Movements / physiology*
  • Female
  • Fixation, Ocular / physiology
  • Head / physiopathology
  • Humans
  • Longitudinal Studies
  • Male
  • Nystagmus, Congenital / physiopathology*
  • Nystagmus, Congenital / surgery*
  • Oculomotor Muscles / physiopathology
  • Oculomotor Muscles / surgery*
  • Ophthalmologic Surgical Procedures*
  • Posture
  • Visual Acuity / physiology
  • Visual Fields / physiology
  • Young Adult