A number of conditions may cause a person to depress the chin in order to improve visual perception.
Esotropia or exotropia:
(1) V pattern esotropia with fusion in upward gaze
(2) A pattern exotropia with fusion in upward gaze
Palsies:
(1) bilateral superior oblique muscle palsy
(2) inferior rectus muscle palsy
(3) progressive supranuclear palsy
(4) supranuclear lesion with down gaze palsy
Miscellaneous causes:
(1) photophobia
(2) uncorrected low-degree myope
