Visual fields of the four possible combinations of left HH and strabismus, constructed from interpolated plots of monocular observers.

[28] (Top row) The top plots depict visual fields when the right eye fixating and in primary position of gaze, while the left eye is fixating in the two bottom plots. (A) Left XT of 12° (20 prism diopters) expands the central field of view left of the vertical meridian. (C) Right ET of 12° expands the central field of view to the left similarly but reduces the field of view at the far right periphery. This may be beneficial despite no net gain in horizontal field span. (B&D) In left ET and right XT there is no visual field expansion. The small reduction on the right temporal field is due to obstruction by the orbit. In all cases large regions of the visual field, including the central view may be diplopic and/or affected by binocular visual confusion. Esotropia causes contralateral monocular peripheral visual field reduction (B, left eye) due to the center of eye rotation behind the pupil. This causes the nose to block more of peripheral nasal field as the eye adducts. Conversely, exotropia (A, left eye) causes monocular peripheral expansion nasally.