1. Incision.
2. Iridectomy.
3. Opening the lens capsule.
4. Delivery of the lens.
5. Toilet of the wound.
[Illustration: FIG. 90. IRIS FORCEPS. Care should be taken to see that
the teeth dovetail properly.]
[Illustration: FIG. 91. IRIS SCISSORS. Their cutting power should be
tested on wet cigarette paper before use.]
[Illustration: FIG. 92. A VECTIS. It should be made of stiff steel.]
[Illustration: FIG. 93. PAGENSTECHER’S SPOON. It is an advantage to bend
the shaft near the spoon to a right angle.]
=First step.= _The incision._ The surgeon, standing behind the patient’s
head and holding the knife with the edge directed upwards, in the right
hand for the right eye and in the left hand for the left, fixes the eye
with a pair of forceps held in the other hand, by grasping the
conjunctiva below and to the inner side as close to the limbus as
possible (Fig. 94). Most continental surgeons stand in front of the
patient and cut upwards. The point of the knife is then passed on the
flat into the anterior chamber from the outer side, 1.5 millimetres
behind the corneo-sclerotic junction.
[Illustration: FIG. 94. LENS EXTRACTION. Showing the position of the
hands when making a section upwards with a Graefe’s knife.]
It is first directed downwards and inwards until the chamber is
penetrated (Fig. 95). The knife-point is then directed horizontally and
passed across the anterior chamber in a line parallel with an imaginary
tangential line across the top of the cornea. The counter-puncture is
then made, the knife emerging 1 millimetre behind the corneo-sclerotic
junction (Fig. 96). In making the counter-puncture the beginner is apt
to go too far back in the sclerotic owing to the angle of the chamber
being placed behind the limbus; he should therefore aim for a point
about 1 millimetre inwards from the limbus. The knife is next made to
cut upwards by a sawing movement so that a flap is formed of corneal
tissue about 3 millimetres in breadth (a breadth and a half of a new
Graefe’s knife), the upper margin being at the corneo-sclerotic
junction. When the corneal flap has been made, the knife should lie
beneath the conjunctiva, from which a flap about 3 or 4 millimetres in
length should be formed. The knife-edge is then turned forward and made
to cut its way out. In making the section, care must be taken not to
prick the patient’s nose or eyelid with the point of the knife, as it
may cause him to move his head with disastrous results. This is more
likely to happen with patients who have sunken eyes.
[Illustration: FIG. 95. THE KNIFE ENTERING THE ANTERIOR CHAMBER IN
CATARACT EXTRACTION. The point of the knife is directed downwards and
inwards.]
[Illustration: FIG. 96. MAKING THE COUNTER-PUNCTURE IN CATARACT
EXTRACTION. The counter-puncture is shown completed.]
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