The nature of head postures in congenital nystagmus
R. V. Abadi and J. Whittle
Department of Optometry and Vision Sciences, University of Manchester Institute of Science and Technology, England.
We investigated the factors that determine the nature and extent of
abnormal head postures in patients with congenital nystagmus. The head
positions and eye movements of 16 patients were monitored while they
adopted a variety of gaze positions. Five patients displayed a single head
posture and four displayed multiple head postures. Six of the nine head
postures matched the minimum intensity zone. The extent of the head posture
was also found to be dictated by the velocity distribution of the slow
phase, the nystagmus beat direction, and the neutral zone. Our results
suggest that the surgical management of a head posture should not always be
based only on the relocation of the minimum intensity zone to the primary
gaze position.
