Instruments. Speculum, fixation forceps, Beer’s knife, scissors, scoop and stitches.
Operation. A general anæsthetic is necessary.
First step. The eye is transfixed about 4 mm. behind the corneo-sclerotic junction with a Beer’s knife, which is made to cut out upwards (Fig. 135). The flap of corneal and scleral tissue is then seized with forceps and the cornea removed entirely by completing the incision in the sclerotic round it with scissors (Fig. 136).
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Fig. 135. Mules’s Operation. First step. Excision of the cornea. | Fig. 136. Mules’s Operation. The completion of the excision of the cornea with scissors. |
Second step. The contents of the globe are then eviscerated by means of a spoon, and the cavity flushed out with 1 in 4,000 perchloride of mercury lotion. Great care should be taken to remove all portions of the uveal tract; this is best ensured by visual inspection after the hæmorrhage has ceased. The interior of the sclerotic should appear perfectly white.
Third step. Although not absolutely necessary, and inadvisable in the case of a septic globe, a single suture may be passed through the centre of the wound in the conjunctiva and sclerotic.
Complications. As the operation is not infrequently performed for panophthalmitis, much swelling of the lids and discharge from the socket may take place after the operation; these symptoms usually subside in the course of a few weeks without further trouble. The interval which must elapse before an artificial eye can be worn is considerably longer than after enucleation.
MULES’S OPERATION
Mules’s operation is the insertion of a celluloid globe into the sclerotic after evisceration, followed by closure of the scleral wound over it. In both this and Frost’s operation a better stump is formed, so that more movement may be obtained in the artificial eye which is subsequently worn over the inserted globe.