Displacement of the crystalline lens from its normal position in the eye. Lens dislocation is almost always caused by an injury that ruptures the fibres connecting the lens to the ciliary body. In Marfan’s syndrome, these fibres are particularly weak and lens dislocation is common.A dislocated lens may produce severe visual distortion or double vision, and sometimes causes a form of glaucoma if drainage of fluid from the front of the eye is affected. If glaucoma is severe, the lens may need to be removed. (See also aphakia.)
a lens with fine parallel lines (almost invisible striations) across its width, used in various vision tests; for example, to test suppression and abnormal retinal correspondence. [B. Bagolini (20th century), Italian ophthalmologist]... bagolini lens
(luxation) n. displacement from their normal position of bones meeting at a joint such that there is complete loss of contact of the joint surfaces. It usually results from trauma (e.g. dislocation of the shoulder, which is common in sports injuries, and dislocation of the mandible from the temporomandibular joint) but may be congenital, in which case it usually affects the hip (see congenital dislocation of the hip). In a traumatic dislocation the bones are restored to their normal positions by manipulation under local or general anaesthesia (see reduction). Compare subluxation.... dislocation
(CDH) an abnormality present at birth in which the head of the femur is displaced or easily displaceable from the acetabulum (socket) of the ilium, which is poorly developed; it frequently affects both hip joints. CDH occurs in about 1.5 per 1000 live births, being more common in first-born girls, in breech deliveries, and if there is a family history of the condition. The leg is shortened and has a reduced range of movement, and the skin creases may be asymmetrical. All babies are routinely screened for CDH at birth and at developmental check-ups by gentle manipulation of the hip causing it to be reduced and dislocated with a clunk (see Barlow manoeuvre; Ortolani manoeuvre). The diagnosis is confirmed by X-ray or ultrasound scan. Treatment is with a special harness holding the hip in the correct position. If this is unsuccessful, the hip is reduced under anaesthetic and held with a plaster of Paris cast or the defect is corrected by surgery. Successful treatment of an infant can give a normal hip; if the dislocation is not detected, the hip does not develop normally and osteoarthritis develops at a young age.... congenital dislocation of the hip
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