Sometimes better vision can be ob tained by enlarging tbe aphakic portion of the pupil by a small iridectomy. Other things being equal, this portion is to be preferred for correction on account of the greater size of the retinal images so obtained.
When the dislocation is complete, the lens being in the vitreous, the case is precisely similar from a refraction stand point to one of aphakic after cataract extraction. fnder all conditions two pairs of glasses are required: one for dis tance and another for reading or working distance.
But in many cases other symptoms be sides disturbances of vision are present at an earlier or later stage in the case. In cases of partial dislocation pressure of the lens against the ciliary margins of the iris and the ciliary body may set up glaucomatous symptoms. In this case. if removal of the lens be not deemed feasible, an iridectomy may be made at the point where the lens is in contact with the iris.
Removal of the partially-dislocated lens is always difficult, and apt to be com plicated with loss of vitreous, on account of the condition of the suspensory liga rnent, which is either congenitally defi cient or damaged by traumatism.
Great stress laid upon the importance of the immediate use of a mydriatic in injury of the lens. 111illikin (Jour. Amer. Med. Assoc., Sept. 3, '92).
In a case of secondary glaucoma from partial dislocation of the lens into the anterior chamber, removal of the lens 1N-as followed by immediate cessation of all pressure symptoms. In this case the loNNer half of a densely-cataractous lens had pushed its way through the pupillary opening and had pressed the iris in this Position far back behind it. To efTect its removal a peripheral incision was made in the lower outer third of the cornea. A wire loop was introduced and the lens was extracted without the loss of any vitreous, obtaining a clear and round pupil. Oliver (Wills Eye-Hosp. Reports, vol. i, p. 1, '95).
Slight partial dislocation of the lens can be cured by the continued use of atropine, which gives the zonula a chance to repair, or by eserine if vision is im proved by its instillation and where the tests show that atropine produces a still further tilting of the lens. Dunn (Va. Med. Semimonthly, Jan. 2, '97).
When the lens is dislocated into the anterior chamber, extraction is tively easy, and, inoreover, absolutely necessary. lf it is not done, vision is evitably lost. The lens is fixed in the anterior chamber by the use of miotics or the introduction of Agnew's bident, and the ordinary corneal incision for cata ract made. Delivery has to be accom plished by means of the vectis, wire loop, or sharp hook-.
Six cases of successful extraction of luxated lenses by the assistance of the Agnew bident. In the use of the instru ment, the lens should not be pressed too far into the anterior chamber, as in per forming the after-section for the extrac tion of the lens; the iris and the lens are thus rendered more liable to be cut through, or the section itself may be forced to insufficient size. Pomeroy (New England Med. Mthly., May, 'S9).
Traumatically dislocated lens success fully removed from anterior chamber of an eye presenting glaucomatous symp toms. After transfixing the lens with a stop-needle, extraction was accomplished by introducing a wire loop through a broad peripheral corneal incision; owing to an irreducible prolapse of the iris, an ridectorny had to be made. Healing was uninterrupted, and normal vision with a correcting glass was regained. Oliver (Annals of Ophthal. and Otol., July, '92).
Three completely luxated lenses suc cessfully removed by the aid of an elec tric photophore, which was made to illuminate the interior of the eye. After the illumination had been effected a pointed hook was introduced through the sclera to fix the lens, which latter was held in position while an assistant lacer ated the capsule with a cystitome that had been introduced into the anterior chamber. The resulting soft cataracts were removed, six or eight days after, by aspiration. Ahadie (Recueil d'Ophtal., Aug., '92).
Case of luxation of the lens into the vitreous which caused no symptoms for three years, and then from some unknown cause, the lens having passed into the anterior chamber, the eye became very painful. Massage, which, being done with the fingers on the closed lids, forced the cataractous lens back into the vitre ous. To prevent recurrence, the pupil WaS kept small by miotics. Boggi (Ann. di Ottal., xxv, p. 77).