Registered eye position: short- and long-term effects of botulinum toxin injected into eye muscle.

Botulinum toxin is sometimes injected into human eye muscles as an alternative to surgery in the correction of strabismus. Within minutes of botulinum injections into ungulate eye muscles, proprioceptive discharge from muscle spindles decreases dramatically. It is only over 7-48 h, however, that surgically treated strabismus patients usually show an altered proprioceptive signal about eye position, presumably from the palisade endings attached to the global multiply innervated fibers.

The Cyclops effect in adults: sighting without visual feedback.

When asked to look through a tube, younger children place it at the bridge of the nose, and not over one eye: the Cyclops effect. This is a natural response to a median plane egocenter. With maturity, the Cyclops effect disappears as we learn to overcome the consequences of an egocenter between the two eyes, and instead, to use the "preferred" eye.

Learning to look with one eye: the use of head turn by normals and strabismics.

When asked to look through a tube, young children (normal, strabismic, monocularly enucleated) place it between the eyes, while older children turn the head or shut one eye. We videotaped 174 children (normals and strabismics, 2-17 yr of age) and 16 normal adults to find out when and why head turn occurs. In learning to look with one eye, children progressed through a sequence of four responses, categorized by age or amount of head turn.

Egocenter location in children with strabismus: in the median plane and unchanged by surgery.

Purpose: Previous studies have shown that there are spatial localization shifts after horizontal strabismus surgery when a patient performs an open-loop pointing task. After monocular enucleation, an adult will also show a shift in the pointing response. Other studies have shown that in children who underwent enucleation, the egocenter location shifts toward the remaining eye.

Visual alignment from the midline: a declining developmental trend in normal, strabismic, and monocularly enucleated children.

Children, 1.8 to 5.0 years of age, were asked to sight through a tube at targets.