abnormal position of the crystalline lens of the eye (eye, human). The dislocation, which may be congenital, developmental, or acquired (typically via trauma), is usually caused by abnormalities of or injury to a portion of the suspensory ligaments (ligament) (called zonular fibres) that anchor the lens to the ciliary muscle. Problems associated with lens dislocation include monocular double vision, decreased vision, and astigmatism.

Lens dislocation is a feature of a number of congenital and hereditary disorders, including Marfan syndrome and Ehlers-Danlos syndrome. Marfan syndrome is associated with cardiac and skeletal abnormalities, whereas Ehlers-Danlos is a condition marked by great elasticity of the skin and double-jointedness. The usual management of the lens dislocation is improvement of vision by means of eyeglasses or rigid contact lenses, although surgical lens removal may eventually be necessary.