104 Vi

Soft shell stain

Akahoshi T
Tokyo

For a successful phacoemulsification, performing a complete
capsulorhexis is the most important point of the surgical proce-
dures. However, sometimes capsulorhexis is difficult due to the
poor visibility of the capsule in the cases with white mature
cataract, dense nucleus or corneal opacity. Capsular staining with
a dye facilitates the visibility, however, often causes severe cor-
neal endothelial damage, if the dye solution was applied into the
anterior chamber formed by the air. In order to stain the capsule
more deeply and safely, Soft Shell Stain technique using Visco-ICG
solution was developed. In case of a white mature cataract, it is
also important to decrease the vitreous pressure by administra-
ting a high osmotic agent intravenously prior to the surgery. Even
though the capsule is successfully stained, higher intracapsular
tension will cause the capsular tear running to the periphery du-
ring the capsulorhexis procedure. I usually use Glyceol (10 % gly-
cerin + 5 % fructose + 0.9 % NaCl) or Mannitol (15 % mannitol) 10
ml/Kg body weight, 90 minutes prior to the operation. To protect
the corneal endothelium from the dye, dispersive type of the
viscoelastic material, Viscoat is most useful. To apply Viscoat ef-
fectively on the endothelial surface, soft shell technique was mo-
dified. Small amount of Viscoat is injected into the anterior cham-
ber, followed by the cohesive viscoelastic material, Provisc filling
up the anterior chamber completely. The Provisc is used just to
spread the Viscoat uniformly on the corneal surface. Then the
Provisc is aspirated with an I/A tip. Cohesive Provisc can be easily
removed, while transparent soft shell of Viscoat will remain on
the surface of the corneal endothelium. To make the Visco-ICG
solution, 25 mg of ICG powder is dissolved in the 0.5 ml distilled
water completely and then one vial of Provisc is added into the
bottle. By shaking vigorously, thick Visco-ICG solution is made up.
The solution is applied with a special canula (ASICO AE. 7272) so
as to paint the capsular surface. As the endothelial surface is
completely coated by the Viscoat, the Visco-ICG solution can be
filled up the anterior chamber. Immediately, the Visco-ICG solu-
tion is removed with an I/A tip. The anterior chamber is then
filled with Viscoat again and capsulorhexis is performed with an
excellent visibility of the capsule. Compared with the conventio-
nal ICG solution, which was dissolved in the BSS, the Visco-ICG
solution can attain much deeper and uniform staining of the
capsule. Scanning electron microscopic observation of the rabbit
cornea guaranteed the safety of this technique. In our clinical
observation with a specular microscope of more than 50 cases,
there was no significant difference in the corneal endothelial cell
loss, between the normal cataract and white mature cases which
were applied this technique.



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