● Karton-CI is the clear, glutinous agent on the right side of the photo below. Karton-CII is the yellow agent on the left. Note that what we call "Karton-C" is a mixture
of '-CI' and '-CII."
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● When these two agents are mixed, they begin to gel right away as shown
in the photo below.
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Karton agents are safe on your hands or tissues
during experiments. The ingredients are gel chemicals whose composition
is mainly polyvalent alcohol that reacts with water to harden. They are,
however, inflammable, so restrain from smoking during experiments and keep away from the fire devices.
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● Overall Steps of Procedures:
Inject a dose of Karton-C beneath the anterior capsule of a butchered pig's eye. ⇒ When
the Karton-C has gelled, ⇒ practice performing a CCC on the chemically
degenerated pig's eye with a cystotome needle and/or cystotome forceps.
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● Procedures:
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| 1) |
Make an opening around the equator of the sclera with a stab knife or a
slit knife. It is advisable to make a fairly large opening because
it will be easier to spot it later.
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| 2) |
Then, set a needle on a 1.0 ml syringe and draw in 0.20 ml of 'Karton-CI'
out of its container slowly. Since it is a glutinous liquid, air
bubbles may appear in the syringe, but there is no need to worry about
it now.
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Next, draw in 0.1 to 0.2 ml of 'Karton-CII' into the same syringe. During
these suction processes, some air (approx. 0.1ml) may go into the syringe,
but no need to take out the air at this point. This is how a gelation agent 'Karton-C' is produced.
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Leave the syringe as it is without stirring the contents till you are ready
for its use. The agents inside the syringe are unevenly mixed at
present, but we'll mix them evenly later.
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| 3) |
When you are ready to use Karton-C, make sure at first that the needle is securely connected to the syringe. Then by using the air (approx. 0.1ml) left in the syringe, shake the syringe to mix the agents inside. Confirming that the agents have not begun to gel inside the syringe, stand the syringe upright and push out the air from the tip of the blunt needle. Finally, bend the whole needle and curve it at about 90 degrees.
Note: Once the agents are mixed, their chemical reaction is fast and will begin
to gel right away, so please use the mixture within approximately 5 minutes.
If it is left unused for over 10 minutes, Karton-C will gel inside the syringe, and you will no longer be able to use the agent for
your practice.
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| 4) |
Insert the Karton-C syringe prepared in 3) through the scleral opening
made in 1) into the eye ball. Steadily advance the needle toward
the posterior pole of the posterior capsule and pierce into the posterior
capsule. (You'll feel a snap when penetrating.) Then advance
the needle until it is right under the center of the anterior capsule.
(Do not lose the tip of the needle.)
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| 5) |
With the tip of the needle, slightly raise the anterior capsule and secure
some space to inject Karton-C.
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| 6) |
When you have secured some room beneath the anterior capsule, carefully
inject Karton-C, allowing the agent to spread in a round shape in the center
area of pupil. Turn the tip of the blunt needle in different directions,
so that the agent will spread evenly.
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Precautions: The above procedures, from 2) to 6), need to be done swiftly without losing
much time. Both agents, CI & CII, are so time-adjusted that they
gel quickly in order to provide a quick preparation for your practice.
Once they are mixed, the approximate time limit is 10 minutes at most. After that, they'll begin to gel, and you will no longer be able to use the mixture in most cases.
For keeping and saving the expensive blunt needle, remove all that is left
inside the needle by aeration, then you will be able to use it repeatedly.
Once you get used to the procedures, theoretically one dose of Karton-C
should make two to three models for CCC practices. However, considering
the fast gelation of the agent, we advise a one-time use for each dose.
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| 7) |
The Karton-C injected in the space beneath the anterior capsule will immediately
begin to harden, therefore, the injection process should be carried out
without much interruption. Stop injection when the spread of the agent
seems sufficient over the mydriatic pupil.
The maximum amount of Karton-C that can be injected into the space is 0.20 ml. An overdose of the agent will cause an overflow into the anterior chamber, posterior capsule, and vitreous body, and result in failure of producing an appropriate model for your practice. A little less amount is better than an overdose. We are sure that you will soon learn the best amount in a careful
practice.
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| 8) |
The consistency of Karton-C totally depends upon its setting time, and cataract models of different hardness -- from soft to rock-hard --
can be produced. For the practice of a soft nucleus cataract or a
hyper mature cataract, a few minutes of setting time is appropriate. When
the setting time is set for more than 15 minutes, the solidity will approximate
that of a mature human cataract.
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| 9) |
Furthermore, the anterior capsule of an untreated pig's eye tends to be
very thick and sticky, thus very difficult to perform a CCC. Whereas
the anterior capsule treated with 'Karton-C' is softer and more vulnerable as that of a human's. Even the anterior capsule flaps can be turned over as real as those of a human's, which allows you to practice performing
a CCC on an unstable type of a human cataract. (Note: This turning
technique is essential in an actual human CCC.)
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| 10) |
Well, finally, 'the anterior subcapsular cataract on a butchered pig's eye' is produced for practicing a CCC.
The next step is to make a side port with a stab knife about the limbus
or sclerocorneal area. When the side port is made, apply viscoelastic
material into the anterior chamber.
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| 11) |
A) For those who plan to perform a CCC with a cystotome needle, bend the
needle and insert it into the anterior chamber through the side port of
your choice. You may begin your CCC practice now.
B) For those who plan to perform a CCC with cystotome forceps, you can
either make an opening at 12 o'clock position around the circumference
with a slit knife or, after completing with the scleral flaps, put into
the anterior chamber with a slit knife. Then, again, apply viscoelastic
material into the anterior chamber to secure the chamber. Finally,
begin your CCC practice with Inamura cystotome forceps or the like.
For those who wish to perform a 'temporal approach,' modify the above procedures
as to bring about the best result.
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| 12) |
As already mentioned earlier, in the procedure 11), folding of the scleral
flaps is even possible now, which is impossible with an untreated pig's
eye. Also, as mentioned in 9), the chemically generated scleral flaps
treated by Karton-C are softer and more vulnerable like those of a human's,
which is a perfect model to practice for an unstable human cataract on.
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Nevertheless, it is not advisable for beginning surgeons to practice performing a CCC on a non-stained anterior capsule. Until you get a firm grip on the procedures, we advise you to conduct 'Staining Method', as shown in the photos below.
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