[Illustration: FIG. 124. AUTHOR’S CHAIR FOR THE LOCALIZATION OF FOREIGN BODIES IN THE EYE BY THE X-RAYS. A is a rifle sight for centring the anode, C, on the cross wire, B, behind which the photographic plate is subsequently placed. P is the screw clamping the head-piece on to the patient’s head. Q is the screw for regulating the height of the tube and the distance from the patient. R is the screw for regulating the height of the head-piece. The inset shows the arm carrying the tube more highly magnified. E is the sliding arm carrying the tube for lateral displacement marked for stereoscopic photographs. F is the pointer for marking the position of the anode. D is the screw for clamping when in position.] =Operative treatment.= If the injury be a recent one and the foreign body a metal of magnetizable properties, it is best removed by an electro-magnet after localization by the X-rays (Fig. 124). Sideroscopes have been used, but are not so satisfactory. If the foreign body be non-magnetizable, such as a piece of copper cap or manganese steel, an attempt may be made to remove it with forceps after localization. If the foreign body be embedded in the lens it is often advisable to extract the lens together with it. If the foreign body be of glass, and it be only small, it is usually best left alone, unless capable of easy removal, _e.g._ if it be situated in the anterior chamber; the eye will often tolerate the presence of glass provided it be aseptic. _The eye should be removed_-- (i) If the wound be obviously septic. (ii) If the wound be very large, more especially if the lens be injured. (iii) If the foreign body be a large piece of metal and cannot be extracted. (iv) If the eye does not settle down after one of the operations described below, especially if irido-cyclitis with keratitis punctata should have supervened. =If the injury be of long standing.= It is of little use as a rule attempting to extract a foreign body from the eye after three days, unless it be loose in the vitreous or embedded in the lens, as it becomes surrounded by lymph. Under these circumstances it is better to leave it alone, or, if it be causing signs of irritation, to enucleate the eye. ELECTRO-MAGNET OPERATIONS Magnets for the removal of magnetizable foreign bodies from the eye are of two types--(1) a small magnet, which is inserted into the globe, (2) a giant magnet, which is used to attract the foreign body in the eye from the outside.