If only small amounts of torsion are present,<unk>  may be without symptoms entirely and may not need correction, as the visual system can compensate small degrees of torsion and still achieve binocular vision (see also: cyclodisparity, cyclovergence). The compensation can be a motor response (visually evoked cyclovergence) or can take place during signal processing in the brain. In patients with<unk>  of vascular origin, the condition often improves spontaneously.<unk>  cannot be corrected with prism spectacles in the way other eye position disorders are corrected. (Nonetheless two Dove prisms can be employed to rotate the visual field in experimental settings.) For cyclodeviations above 5 degrees, surgery has normally been recommended. Depending on the symptoms, the surgical correction of<unk>  may involve a correction of an associated vertical deviation (hyper- or hypotropia), or a Harada–Ito procedure or another procedure to rotate the eye inwards, or yet another procedure to rotate it outwards. A cyclodeviation may thus be corrected at the same time with a correction of a vertical deviation (hyper- or hypotropia); cyclodeviations without any vertical deviation can be difficult to manage surgically, as the correction of the cyclodeviation may introduce a vertical deviation.
Cyclotropia
Exotropia
Esotropia
Ocular dysmetria
Quadrantanopia
Heterotopia 
Pseudomyopia
Presbyopia