Dislocation of the lenses observed in five children of a family of seven whose mother was similarly affected. In none of the cases was the dislocation upward. Miles (Annals of Ophth., Otol., and Lar., July, '06).
Five cases of congenital bilateral dislo cation of the crystalline lens in three suc cessive generations. In all the disloca tion was upward or upward and outward. E. T. Parker (Phila...AIed. Jour., July 16, '98).
A case is on record in which the colo boma of the iris was upward, there being a subluxation of the lens downward.
Although at first partial, congenital dislocation often becomes complete, through degeneration and stretching of the fibres of the zonula; the lens then becomes movable to a degree which varies greatly, not only in the vitreous humor itself, but it may even pass back ward and forward through the pupil: a condition described by Heyman under the title of "spontaneous motility of the lens." So long as a congenital dislocation of the lens remains incomplete, there is no special tendency toward the formation of cataract; but when it becomes complete, and freely movable in the eye, the iin pairment of nutrition thereby involved leads more or less rapidly to its ()pacifica tion. Occasionally a lens dislocated into the vitreous will remain clear for years.
Of all cases of dislocation of the lens, those of traumatic origin are, by far, the eornnionest. The traumatism usually consists of a blow by a blunt instrument, such as the fist or a stone, upon the eye ball; but concussion from a blow upon the side of the head may have the same result. Dislocation is more apt to occur when the vitreous is fluid: a condition which may be accompanied by degener ative changes in the zonula, in old age, and in sclerectasia anterior.
Traumatic luxation of the lens into the anterior chamber usually occurs when the patient is bent forward, the centre of the cornea being struck at that time. When the blow is nearer the periphery the lux ation takes place iu the direction of the force applied. Dujardin (Jour. des Sci ences Med. de Lille, NOV. 13, '01).
Traumatic dislocations present every variety and degree, from the slightest lateral displacement or rotation to com plete expulsion of the lens from the eye ball.
Lens in an eye removed on account of a penetrating wound found to be dislo cated between the ocular conjunctiva and the sclera, where it had become incapsu lated in a mass of inflammatory exudate.
Wescott (Annals of Ophthal. and Otol., Jan., '93).
TWO Instances of traumatic dislocation of the lens into the vitreous, occurring in individuals both of whom had met with a similar accident in the opposite eye some years previously. Noyes (N. Y. Eye and Ear Infirmary Reports, '94).
The traumatism that is the immedi ate occasion of the displacement is often the cause of other ocular lesions, which may, for a time, obscure the diagnosis, and render prognosis more uncertain than would otherwise be the case. The dislocation of the lens may, indeed, be by no means the most important lesion produced. It is common to find rhage in the anterior chamber immedi ately after the injury, the full extent of which cannot be ascertained until ab sorption has taken place: or we may find dilatation and immobility of the pupil, hmnorrhage into the vitreous, or rupture of the choroid, and—especially in myopic eyes—detachment of the retina. In
greater degree of violence the eyeball may be ruptured, usually in the sclera just behind and concentrically with the sclero-corneal junction, and through this rupture the lens—with the iris, choroid, retina, and vitreous—may escape.
Case of traumatic dislocation of the lens, followed by symptoms of fulmi nating glaucoma. Patient made a good recovery after extraction of the lens. Saunders (Brit. Med. Jour., Mar. 2, '89).
Absorption of a crystalline lens that had been luxated into the vitreous during an operation upon the eye for glaucoma. Case occurred in a boy. All children have remarkable tolerance for that which would cause glaucoma in adult eyes. Chacon (Gaceta Med. de Mexico, June 1, '92).
Spontaneous dislocation of the lens may take place while its transparency re mains unimpaired, but it seems to occur more commonly when the lens has be come cataractous, and more especially when the cataract has been allowed to progress to a condition of hypermaturity (Morganian cataract). Although in some cases the displacement occurs without any evident immediate exciting cause, in many the acts of coughing or sneezing determine it. Gunn in 1895 reported a case of quite spontaneous symmetrical displacement of the lenses in a man aged 76. Three months before it failed a re corded examination showed vision, with refraction corrected, to be 6/6 in each eye. Three months after failure both lenses were found displaced downward, their upper edges being visible just within the margin of the dilated pupil, one lens still remaining clear, the other having become opaque. Corrected vision in each eye, 6/6. Fundus normal. It is hardly necess.ary to point out that old age constitutes the main predisposition to spontaneous dislocation of the lens, the immediate pathological factor being an atrophy of the fibres of the suspensory ligament: a condition described by Wedl and Bock as "senescence of the zonula." Symptoms; Appearances; Vision. — Any change in the position of the lens destroys the normal relations between it and the iris, the latter losing its sup port partially or totally, according to the degree of the displacement, or being un duly pressed forward or backward, or dis tended, according as the lens is tilted against portions of the posterior surface of the iris, dislocated into the anterior chamber, or fixed in the pupil itself. When the dislocation is incomplete the anterior chamber is deeper at the point vacated by the lens, and the iris of the same region is tremulous on quick move ments of the eyes or head. In the slight est degrees of dislocation a slight tremu lousness of one portion of the iris may constitute the only physical sign of the lesion, but is an absolute indication that the iris no longer rests on the anterior cat stile of the lens. The history of jury and the condition of vision will be necessary to lead to a correct diagnosis.