When the lens is completely dislocated into the vitreous chamber, and no com plications have arisen, vision resembles that of an eye after cataract extraction, and the condition is exactly similar to that brought about by the operation of reclination, conching.
The patient regains good vision with the aid of strong convex lenses, which have to be adjusted for distance, and also for the near point at which it is desired to read or work.
But in many of these cases complica tions arise which prevent perfect vision from being attained, or in course of time bring about its impairment in varying degree. Thus, iridocyclitis may arise and destroy vision and even set up sympa thetic disease in the fellow-eye. Or glau comatous tension may occur, with the same result, so far as sight is concerned.
Four cases of spontaneous luxation of the lens, two of which were congenital. In one the luxation was bilateral. In three instances the lens had to be ex tracted, after years of quiet, upon ac count of violent glaucomatous attacks. Armaignac (Jour. de Med. de Bordeaux, June 23, '95).
Case of secondary glaucoma following partial dislocation of lens; removal of lens; cessation of all pressure-symptoms. Oliver (Wills Eye-flosp. Reports, vol. i, p. 1, '95).
Case in which a lens dislocated into the vitreous during a cataract-operation set up so much sympathetic disturbance six months later that enueleation was neces sary. K. floor (Wien. med. Woch., Aug. 22, '96).
Progress and Results. — Congenital dislocations are always incomplete, and the lens shows no special tendency to become opaque: good evidence that its nutrition is unimpaired. ln some cases, however, the displacement increases, and coniplete dislocation into the vitreous or anterior chamber, or alternately into each, finally occurs. The latter condi tion is predisposed to by abnormal small ness of the lens: a common characteristic in cases of ectopia, which permits its easy passage through the pupil. When this state of complete luxation has been attained, the lens-substance is liable to deteriorate and become opaque. Strik ing against portions of the uveal tract the freely-movable lens may set up irido cyclitis, and disorganization of the eye and destruction of vision result. Or, as previously stated, secondary glaucoma may become established and finally lead to blindness.
In two cases, father and daughter, seen In the practice of the writer. the father.
d had opaque lenses freely floating .11 the ttreons, and sometimes passing through the pupil into the anterior r. ith occasional glaucomatous au:hiss. :Lk ays relieved by paracentesis. The daughter presented typical examples of ectopia lentis. both lenses being sta tionary and quite clear. Good vision was obtained with convex lenses.
Although there are eases in which a small lens may pass freely through the pupil. az; a rule, a lens dislocated into the anterior chamber sets up violent inflam mation. The irritation caused by its pressure on the anterior surface of the iris excites contraction of the pupil and iritis. which fix it firmly in position. Or a few white spots indicate the presence If adhesions between the lens and cornea, caused by inflammation of the latter. There is glaucomatous tension and rapid extinction of sight. As a result of the increased tension, ectasia of the anterior part of the sclerotic occurs, and a general enlargement of the eyeball.
Spasm of the sphincter iridis, just re ferred to, may occur while the lens is in the act of passing. through the pupil. There then arise violent inflammatory glaucomatous symptoms.
In a ease in which dislocation of the lens into the vitreous occurred as one of the results of the lodgment of a small piece of s.teel in the eye, the lens was found, after enucleation on account of persistent pain due to absolute glaucoma, to be completely opaque and black. The F.ource of the pigment was quite evident. for the ehoroid was apparently entirely devoid of it. The foreign body was en cysted in fibrous tissue attached to the retina near the equator. The enuclation was performed about twenty-five years after the injury. the eye having been blind for many vears.
Treatment. —When DO symptoms other than impairment of vision exist, suitable glasses may be prescribed; but when one eye only is the subject of dislocation, the other being normal and of good visual acuity, the patient will get on better without a correcting glass, depending on the good eye for clear vision. In cases of subluxatiou, the margin of the lens lying in the pupil, the kind of lens ordered depends upon whether better vision can be obtained by correcting the portion of the pupil containing the lens, the myopic area, or the aphakie, hyper metropic arca. This can, of course, only be ascertained by actual experimentation.