title: Bidirectional Synergistic Vergence.
abstract: A 14-year-old boy presented with left ptosis and squint since his childhood. In primary position he had left hypotropia with ptosis (levator function 2 mm). With elevation of the right eye, the left eye depresses and adducts; with depression of the right eye, the left eye elevates and abducts. Forced duction test revealed no restrictive pattern. The synergistic divergence described in the literature was unidirectional and wholly compatible with inferior rectus co-contraction. But this case is bidirectional, and the aberrant upward movement cannot be explained by rectus muscle co-contraction. The two vertical rectus muscles show reciprocal misinnervation, or this effect could be coming from co-contraction of one of the oblique muscles for the movement in one direction.
authors.affiliation: Department of Ophthalmology, Kayseri Military Hospital , Kayseri, Turkey.
authors.forename: Gokcen
authors.initials: G
authors.lastname: Gokce
authors.affiliation: Department of Ophthalmology, Van Military Hospital , Van, Turkey.
authors.forename: Cem
authors.initials: C
authors.lastname: Ozgonul
authors.affiliation: Department of Ophthalmology, Kafkas University , Kars, Turkey.
authors.forename: Halil Huseyin
authors.initials: HH
authors.lastname: Cagatay
authors.affiliation: Department of Ophthalmology, Kafkas University , Kars, Turkey.
authors.forename: Metin
authors.initials: M
authors.lastname: Ekinci
authors.affiliation: Department of Ophthalmology, Medical Park Hospital , Ankara, Turkey.
authors.forename: Osman Melih
authors.initials: OM
authors.lastname: Ceylan
authors.affiliation: Department of Ophthalmology, Gulhane Military Medical Academy , Ankara, Turkey.
authors.forename: Fatih Mehmet
authors.initials: FM
authors.lastname: Mutlu
keywords: Divergence; innervation; oblique muscle; oculomotor nerve; rectus muscle