Surgery and compensatory head postures in congenital nystagmus. A longitudinal study
R. V. Abadi and J. Whittle
Department of Optometry and Vision Sciences, University of Manchester Institute of Science and Technology, England.
Null zones and head postures were studied in two patients with idiopathic
congenital nystagmus who had been carefully selected from a larger group of
patients who had nystagmus with compensatory head postures. Oculomotor and
sensory features of the two patients indicated that they would have a
reasonable chance of profiting from surgery. Neither patient had a periodic
alternating or manifest latent nystagmus or any ocular disease of the
fixating eye. Postoperative evaluation of the head posture and the
nystagmus behavior of both patients was carried out over a period in excess
of 6 years. Neither of the patients readopted a head turn, and visual
acuity was found to be equivalent to that prior to surgery when using the
null zone. In one of the patients the postoperative null zone was located
in the primary position, while in the other the null zone was decreased
from an eccentricity of 30 degrees to 15 degrees. These results suggest
that the position of the postoperative null zone is not always an accurate
predictor of head turn.
