POINTING ERRORS IN STRABISMICS - COMPLEX PATTERNS OF DISTORTED VISUOMOTOR COORDINATION

Monocular eye-hand coordination was tested in a pointing experiment in the central and peripheral visual field of each eye of strabismic and anisometropic amblyopes, strabismic alternators and normal controls. In the normal controls, pointing was accurate in the central visual fi eld. Towards the periphery, normal observers showed a varying amount o f undershoot as well as increasing uncertainty. The pointing pattern w as similar in the two eyes of these subjects. Increased uncertainty of pointing responses was found in most amblyopic eyes as compared to th e dominant eyes. Three strabismic amblyopes and one strabismic alterna tor also had systematic pointing errors (i.e. systematic differences b etween pointing under the control of the dominant as compared to the n ondominant eye). The pointing pattern was not uniform across the visua l field in some of the strabismics, but was composed of areas of large r and smaller pointing errors. Larger pointing errors (i.e. larger dif ferences between the dominant and nondominant eyes) were usually found in the central visual field. These errors were not closely related to the angle of squint. The clinical history of the strabismics seems to be an important factor for the occurrence of pointing errors.