HETEROPHORIA

The Measurement of Heterophoria.

Etiology of Heterophoria and Heterotropia

In heterophoria there is a relative deviation of the visual axes held in check by the fusion mechanism, whereas in heterotropia there is a manifest deviation of the visual axes. The relative position of the visual axes is determined by the equilibrium or disequilibrium of forces that keep the eyes properly aligned and of forces that disrupt this alignment. Clearly, the fusion mechanism and its ...

The relationship between fixation disparity and heterophoria.

Twenty-five asymptomatic subjects with normal binocular vision underwent determination of the magnitude and direction of their heterophoria and their fixation disparity. Fixation disparity was measured at a 2-m fixation distance with the phase-difference haploscope under conditions simulating those of casual seeing. When combined with careful attention to symmetrical control of accommodation, t...

Oculomotor adaptation to induced heterophoria and anisometropia.

In the first part of the paper we demonstrate that the oculomotor system adapts to prism-induced heterophoria over limited motor fields. In the second part we demonstrate that it can also adapt to an induced anisometropia. When normal subjects are made 3 diopters anisometropic, they initially exhibit a phoria whose magnitude is dependent on eye position. After 21/2 hr of binocular visual experi...

Fixation disparity in relation to heterophoria.

The phenomenon of fixation disparity is of interest in the study of fusional processes in patients with single binocular vision. An understanding of its mechanism is of im­ portance in the pathogenesis of strabismus. The clinical determination of the amount and type of fixation disparity relative to its practical clinical and therapeutic implications has been discussed elsewhere. The present st...