Displacement of the crystalline lens from its usual position within the eye. Lens dislocation is nearly always caused from an injury that ruptures the fibres connecting the lens to the ciliary body. In those people with the genetic disorder Marfa syndrome, these fibres are especially weak; lens dislocation is frequent in these individuals.
A dislocated lens can produce extreme visual distortion or double vision. If it slips forwards, it can cause a form of glaucoma (heightened pressure within the eyeball) if drainage of fluid from the front of the eye is affected. If glaucoma is extreme, the lens could need to be removed.