hypotropia. vertical strabismus. human eyes healthy and with downward gaze position. double vision. cartoon

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