Ocular motility anomalies in developmental misdirection of the optic chiasm

Am J Ophthalmol. 1992 Jan 15;113(1):86-95. doi: 10.1016/s0002-9394(14)75759-9.


A 35-year-old normally pigmented man underwent monocular hemifield visual-evoked potential examinations that indicated a lack of normal decussation of nasal paramacular retinogeniculate fibers in the optic chiasm. We studied effects of this anomaly on ocular motility using electro-oculography and the magnetic search-coil technique. The patient exhibited horizontal congenital nystagmus with a predominantly positive exponential waveform. Horizontal smooth pursuit and optokinetic nystagmus were consistently reversed, independent of eye position in the orbit. Vertical tracking was uniformly normal. Horizontal vestibulo-ocular reflexes recorded in the dark during passive rotation exhibited normal gain and phase, whereas rotation recorded in the light reduced gain. Although active head movements reversed horizontal vestibulo-ocular reflexes, vertical vestibulo-ocular reflexes in light and darkness were normal. Our study suggested an association between a lack of normal decussation of retinal fibers in the optic chiasm, and reversed visual tracking and congenital nystagmus.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Electrooculography
  • Evoked Potentials, Visual
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Neural Pathways / abnormalities
  • Nystagmus, Pathologic / congenital*
  • Nystagmus, Pathologic / physiopathology
  • Optic Chiasm / abnormalities*
  • Optic Chiasm / physiopathology
  • Optic Nerve / abnormalities
  • Optic Nerve / physiopathology
  • Saccades