ABSTRACT
The aim of this study was to assess how accurate stereoacuity is as a measure of control. A retrospective review was carried out of 50 patients with either an intermittent heterotopia, symptom producing heterophoria or convergence insufficiency. In the Orthoptic reports particular note was taken of the Prism Fusion Range, Binocular Visual Acuity, Stereoacuity and Prism Cover Test. The Prism Fusion Range and Binocular Visual Acuity showed reductions which mirrored the deterioration of control of a deviation and they were also a better indicator of the outcome of treatment. Stereoacuity was not shown to reduce with decreasing control of a deviation nor to improve with treatment. Stereoacuity though shown, in previous studies to be linked to the size of a deviation does not show improvement when the angle of deviation is reduced or when a heterophoria is no longer symptom producing.
