exotropia. horizontal strabismus before and after surgery. eye misalignment, cross-eyed condition. human eyes healthy

exotropia eye strabismus outward horizontal squint misalignment crossed amblyopia movement vision double deviation ophthalmology eyeball human disorder optometric iris pupil type anatomy muscle extraocular health convergent heterotropia condition dysfunction farsightedness diverge misaligned diagnosis infographic symptom tropia drift position diplopia binocular gaze comparison patient medical therapy surgery before after