The application of the V-shaped method to capsulotomy shows an even
greater field of usefulness, as this method is par excellence the best
way of incising a delicate secondary capsular cataract. This should
be done under artificial illumination. The pupil should be dilated,
as the area of incision is necessarily smaller than in iridotomy,
and unnecessary wounding of the iris should be avoided. The proposed
capsular opening must be so calculated as to fall within the area of
the undilated pupil, or partly within the coloboma if an iridectomy has
been previously performed.
[Illustration: Fig. 48.--Author’s V-shaped capsulotomy. Plan of first
incision.]
[Illustration: Fig. 49.--First incision completed. Plan of second
incision.]
[Illustration: Fig 50.--Pupil resulting from V-shaped capsulotomy.]
The knife-needle is entered at the upper corneal margin, passed across
the anterior chamber to a point 2 mm. to the left of the vertical
plane (Fig. 48), the capsule punctured by a quick thrust, and the
saw-like incision carried from below upward, as in iridotomy. The knife
is then raised up above the capsule and swung 3 mm. to the right of
the vertical plane (Fig. 49), the capsule is again punctured, and a
duplicate incision carried up to join the first, at the apex of the
converging V (Fig. 50).
Where the pupillary margin is adherent to the underlying capsule, or
the pupillary space is too small, it may be necessary to start the
incision in the iris tissue, a little below the pupil, and then cut
upward until the knife emerges into the pupillary area, thus making
an irido-capsulotomy. The soft iris tissue is easily incised if no
pressure is made with the knife, and the sawing motion is maintained.