(_a_) Imperfect opening of the capsule, which is usually the result of using a blunt cystotome; if capsule forceps are used this difficulty hardly ever arises. (_b_) Too small an incision. The margin of the nucleus may present and not be able to pass the wound. The wound must then be enlarged with the iris scissors and the lens delivered in the ordinary way. Only by experience can the amount of pressure required for the delivery of the lens be gauged. [Illustration: FIG. 98. OPENING THE CAPSULE WITH FORCEPS IN CATARACT EXTRACTION. The forceps are inserted closed, brought in contact with the lens, opened, and the capsule grasped between the blades and withdrawn by a gentle side-to-side movement.] (_c_) A sticky consistency of the cortex is not infrequently found in cases of immature cataract. When the lens presents and cannot be delivered readily it may be helped out by means of the cystotome plunged into its substance, pressure being used on the cornea at the same time. If from these or any other causes the suspensory ligament rupture and the vitreous present in the wound, the lens should be removed with the vectis. The vectis, which should be made of stiff steel, is passed vertically into the incision and behind the lens nucleus by depressing the handle; with a steady gentle pressure forwards it is then withdrawn together with the nucleus. The forward pressure should be such as to prevent the instrument slipping on the nucleus, for if it does so the accident is nearly always followed by a rush of vitreous. A Pagenstecher’s spoon may be used instead of the vectis, and is to be preferred in cases where a small nucleus is suspected, since the latter may slip through the loop of the vectis and fail to be delivered. =Fifth step.= _Toilet of the wound._ After the nucleus has been extracted, all the soft matter should be removed as far as possible by gentle expression with the spoon. The angles of the coloboma in the iris should be replaced by stroking it inwards on its anterior surface with the iris spatula, paying particular attention to the angles of the wound (Fig. 99). The spatula should also be passed throughout the extent of the wound so as to free it from any capsule which may have prolapsed into it. The conjunctival flap is then placed in position by stroking it upwards with the iris spatula. [Illustration: FIG. 99. CATARACT EXTRACTION. Replacing the iris, and any tags of capsule which may be in the wound, with an iris spatula.] =After-treatment.= Atropine is instilled either at the time of operation or at the first dressing, and continued until all signs of redness of the eye have disappeared. The patient should remain in bed for at least ten days, both eyes being bandaged during the first four days. The eye that has been operated on should be covered for at least two weeks; subsequently a shade or dark glasses should be worn. =Modifications.= The operation may be modified in various ways.