The Cause of Cataracts P.6 
CONTENTS of this PAGE
Results 

(4) How does the PRESSURE work on the lens? 


3. Collapse of the cells on the lens equator: gBalloon cell formationh 







<The shortage of oxygen
by some change of the cell 









<The decrease of
the oxygen partial pressure 







<Why does the
oxygen partial pressure in the cell 







Fig.46 Balloon cell formation by David G. Cogan^{4} (The same as Fig.21)

<The
decrease of the oxygen partial pressure in the lens cell> The decrease of ATP production must be the cause
of the insufficiency of ATP. The possible origin as the causes of the decrease of ATP
production left last of all is the decrease of the oxygen partial pressure in
the cell. Why the oxygen partial pressure in the cell decreases due to
the high pressure? Henry's law cannot be applied to this circumstance. The deep sea under
the high pressure is different from this circumstance. The
answer is in the lens equator. The cells on the equator make single layer. Those cells receive
the PRESSURE. In the equator, this pressure
cannot diffuse sideways or downward. This is most important in thinking
about wedgeshaped cataract. On the equator to sideways directions, those cells
crowd densely and are surrounded by the same kind of cells. (Fig.47)
In the downward direction, those cells are on a mass of
hardened fiber cells. Consequently, the cells on the equator cannot slide sideways or move downward.
Therefore, since the pressure cannot diffuse sideways or downward, all of the
pressure presses on the cells sandwiched between the capsule and the mass of
hardened fiber cells on the equator. Depending on how a cell is located
away from the equator, the pressure which the cell receives
gradually becomes weaker. For this reason, the internal pressure of cells on
the equator is higher than that of cells removed from the equator. A pressure difference
arises here. 
Fig.47 The cells on the equator

Fig.48 The
capsule has the ability warping outwards.

To assume the actual PRESSURE put on the
lens, we must think of the power of the capsule in two dimensions. First, we try to fold a fragment
of 60yearold eye's capsule to an angle 70‹. (Fig.49) We assume the length of the fragment is about 300 μm.
Because the capsule is stretched on
the outside, pulling power works on the outside of the angle in the folded
state. The pulling powers, named Power A1 and Power A2 respectively, pull the stretched
portion of capsule. We think the value of the power will correspond to the
value of 3 x 10^{7} dyn/cm^{2}, because the fragment is
stretched to a certain degree. 
Fig.49
We try to fold a fragment of capsule to an angle 70‹.

In the equatorial region of the lens, the power of accommodation by the capsule is
put on the lens. However, when the lens relaxes as the zonule
attached to the angle is pulling the capsule, the
pressure on the lens equator will be nearly zero. In accommodation, each Power A1 and Power A2 pulling on the outside is made by the power of
Young's Modulus of elasticity, and each value of the power, or the pressure
might be 300 N/cm^{2}. This is because the capsule is not being pulled
by ciliary fibers at all in accommodation. It is thought that at that
time, the capsule puts the maximum pressure on the cortex. In the most inside
part of the folded capsule, since this part isn't stretched, each pulling
powers named Power B1 and Power B2 will be always zero
N/cm^{2}. I think that as there is a fulcrum on
the top of the angle, the power starts at that point. Additionally, we assume that
the power named Power C1 summed up Power A1 and Power B1 corresponds really to
1/2 of the number added Power A1 to Power B1. A1 = A2 = 300 N/cm^{2}, B1 = B2 = 0 N/cm^{2} C1 = C2 = (A1 + B1) x 1/2 = (A2 + B2) x 1/2 = 150 N/cm^{2} We regard Power C1 as the power in the anterior capsule, and Power C2 as
the power in the posterior capsule. We assume that the angle of the axis
of C1 is 30‹against the longitudinal axis of the lens, and that the angle
of the axis of C2 is 40‹against the longitudinal axis. These numbers are
rough, approximate
values. The pressure put onto the lens equator,
named Power D is, D = C1 x cos 30‹+C2 x cos 40‹= 150 x 0.87 +150 x 0.77 = 246 N/cm^{2} I think the elasticity of the capsule provokes a pressure of at most 246 N/cm^{2} in the
equator. In the posterior pole, where the curve of the lens surface is acute next
to the equator, the angle of the axis might be about 80‹against the polar
axis. In the same way, although the direction of the pressure is reversed,
the pressure
put onto the lens in the posterior pole, named power Dpolar axis is, Dpolar axis = C1p x cos 80‹+C2p x cos 80‹= 150 x 0.17+150 x 0.17 =51 N/cm^{2 } C1p
and C2p in the posterior pole correspond to each C1 and C2 in the equator. At
the posterior pole, as the capsule is pulled to the maximum extent by zonule in
nonaccommodation, the capsule puts the maximum pressure on the posterior pole in this state, not in accommodation. I
think this pressure is not actually significant at all, and that it is really
very small. I think
that the original or natural shape of the lens without the capsule is near to
the shape in relaxation, and that the original or natural shape of the capsule
without the cortex and the nucleus is near to the shape in accommodation. The
lens without the capsule is, so to speak, a bare lens. Therefore, at a young age, in accommodation the bare lens will pushes the
capsule on the equator, at the same time the capsule pushes the bare lens. The
pressure in the lens is complicated. 
Fig.410 The
oxygen cascade^{ 15}

The Cause of Cataracts P.6 