U.S. patent application number 11/749812 was filed with the patent office on 2007-11-22 for insertion device for intraocular lens.
Invention is credited to Kenichi Kobayashi, Shinobu Toyomane.
Application Number | 20070270945 11/749812 |
Document ID | / |
Family ID | 38420743 |
Filed Date | 2007-11-22 |
United States Patent
Application |
20070270945 |
Kind Code |
A1 |
Kobayashi; Kenichi ; et
al. |
November 22, 2007 |
INSERTION DEVICE FOR INTRAOCULAR LENS
Abstract
An insertion device for an intraocular lens is disclosed which
can prevent leakage of a liquid in the device and can house and
store a lens as well as the liquid. The insertion device includes a
main body including a lens housing portion that houses the lens and
an insertion cylindrical portion that feeds the lens into an eye, a
pushing shaft that moves the lens from the lens housing portion in
the front end direction to push out the lens into the eye through
the insertion cylindrical portion, and a lens holding member that
holds the lens, and is placed in the lens housing portion. The lens
housing portion has a shape that receives insertion of the lens
holding member from the rear.
Inventors: |
Kobayashi; Kenichi;
(Ichikawa-shi, JP) ; Toyomane; Shinobu;
(Ichikawa-shi, JP) |
Correspondence
Address: |
MORGAN & FINNEGAN, L.L.P.
3 WORLD FINANCIAL CENTER
NEW YORK
NY
10281-2101
US
|
Family ID: |
38420743 |
Appl. No.: |
11/749812 |
Filed: |
May 17, 2007 |
Current U.S.
Class: |
623/6.12 ;
606/107 |
Current CPC
Class: |
A61F 2/1664 20130101;
A61F 2/1662 20130101 |
Class at
Publication: |
623/6.12 ;
606/107 |
International
Class: |
A61F 2/16 20060101
A61F002/16; A61F 9/00 20060101 A61F009/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 18, 2006 |
JP |
2006-139560 |
May 18, 2006 |
JP |
2006-139561 |
Jun 2, 2006 |
JP |
2006-155051 |
Claims
1. An insertion device for an intraocular lens comprising: a main
body including a lens housing portion that houses the lens and an
insertion cylindrical portion that feeds the lens into an eye; a
pushing shaft that moves the lens from the lens housing portion in
the front end direction to push out the lens into the eye through
the insertion cylindrical portion; and a lens holding member that
holds the lens, and is placed in the lens housing portion, wherein
the lens housing portion has a shape that receives insertion of the
lens holding member from the rear.
2. The insertion device according to claim 1, wherein the main body
includes a peripheral wall without an opening and a gap at least
from the lens housing portion to the insertion cylindrical
portion.
3. The insertion device according to claim 1, wherein the main body
is an integrally formed member.
4. The insertion device according to claim 1, wherein the main body
has a rear end opening through which the pushing shaft is inserted
into the main body, and the lens holding member is inserted into
the lens housing portion through the rear end opening.
5. The insertion device according to claim 1, wherein a liquid can
be introduced into the main body or is housed in the main body.
6. The insertion device according to claim 5, wherein the liquid is
physiologic saline.
7. The insertion device according to claim 1, wherein the lens
holding member is constituted by a first holding member and a
second holding member which are allowed to contact surfaces
opposite to each other of a marginal portion of the lens.
8. The insertion device according to claim 1, wherein the lens
holding member holds the lens in a state in which a stress is not
substantially applied to an optical portion of the lens.
9. An insertion device for an intraocular lens comprising: an
insertion cylinder that is inserted into an incision formed in an
eyeball and feeds the lens into the eyeball; and a pushing shaft
that pushes out the lens into the eyeball through the insertion
cylinder, wherein the insertion cylinder is provided with a cover
portion that is brought into contact with the eyeball to cover at
least part of the incision into which the insertion cylinder is
inserted.
10. The insertion device according to claim 9, wherein the cover
portion is constituted by a separate member from the insertion
cylinder, and mounted to the insertion cylinder.
11. The insertion device according to claim 10, wherein the cover
portion is tiltably mounted to the insertion cylinder.
12. The insertion device according to claim 9, wherein the cover
portion is formed integrally with the insertion cylinder.
13. The insertion device according to claim 9, wherein the
insertion device supplies a liquid into an eye through the
insertion cylinder.
14. The insertion device according to claim 13, wherein the liquid
is physiologic saline.
15. An insertion device for an intraocular lens comprising: a main
body in which the lens is placed; a pushing shaft that pushes out
the lens from the main body into an eye; and a plurality of elastic
members that are placed between the pushing shaft and the main
body, and have a distance changeable with movement of the pushing
shaft relative to the main body.
16. The insertion device according to claim 15, wherein the
distance between the plurality of elastic members is increased as
the pushing shaft moves in a direction for inserting the lens into
the eye.
17. The insertion device according to claim 15, wherein the
plurality of elastic members include a first elastic member, the
position of which is changeable with respect to the main body with
movement of the pushing shaft, and a second elastic member, the
position of which is unchangeable with respect to the main body
with movement of the pushing shaft.
18. The insertion device according to claim 17, wherein the first
elastic member is secured to the pushing shaft.
19. The insertion device according to claim 17, wherein the second
elastic member is axially movably mounted to the pushing shaft, and
contacts the main body in movement of the pushing shaft to be
prevented from moving relative to the main body.
20. The insertion device according to claim 17, wherein the second
elastic member is secured to the main body.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to an insertion device for
inserting into an eye an intraocular lens that is inserted instead
of a crystalline lens after the crystalline lens is extracted
because of cataract or inserted into an eye in order to cure
abnormal refraction.
[0002] In current operations for cataract, the central portion of
the anterior capsule of an eyeball is ablated, a clouded
crystalline lens is removed by an ultrasonic suction apparatus, and
then an artificial intraocular lens (hereinafter simply referred to
as a lens) is placed in the position of the removed clouded
crystalline lens. When placing the lens in the eyeball, an
operation method for inserting the lens into the eyeball through a
small incision by using the flexibility of the lens and thereby
deforming the lens, e.g. folding the lens into a small shape is the
mainstream.
[0003] In the case of an operation, an insertion device is
frequently used which deforms a lens set in a main body of the
device into a small shape while moving the lens in the main body of
the device by a pushing shaft and pushes out the lens into the eye
from a front end opening of an insertion cylinder (nozzle) inserted
into the incision. This insertion device is used not only for the
operation of cataract but also for a lens inserting operation for
an eyesight correction medical treatment.
[0004] When the lens is inserted into an eye by using the insertion
device, a viscoelastic material such as sodium hyaluronate is
introduced into the main body of the insertion device as a
lubricant so that the lens is smoothly moved and deformed in the
insertion device (see Japanese Patent Laid-Open No. 2004-351196).
Moreover, the viscoelastic material has a function of spreading the
space of the anterior chamber of the eye into which the lens will
be inserted by being introduced into the eye through the insertion
cylinder.
[0005] Further, it has been recently required to use inexpensive
physiologic saline in place of the viscoelastic material.
[0006] However, when the main body of the insertion device is
constituted by a plurality of components assembled to each other,
for example, when a lens setting portion in the main body has a
divided structure or an openable and closable structure, a liquid
such as a viscoelastic material or physiologic saline leaks from a
gap created at the assembled portion. The leaking liquid makes the
insertion device slippery or soils the periphery of the device.
[0007] In the case of a conventional operation, a liquid is
introduced into the insertion device immediately before the
operation, which takes time and places a heavy burden on an
operator or an assistant.
[0008] Further, even if the liquid such as a viscoelastic material
or physiologic saline is introduced into an eye, a large amount of
liquid leaking from a gap between an edge of an incision in the eye
and an insertion cylinder (an amount of leakage outside the eye)
prevents an increase in ocular tension and sufficient inflation of
the anterior chamber.
[0009] To a pushing shaft, an elastic member such as rubber is
frequently mounted for preventing a lubricant introduced into the
main body from leaking from between an inner peripheral surface of
the main body and the pushing shaft, and providing proper
resistance (sliding feeling) to an operation of the pushing
shaft.
[0010] In the conventional insertion device, the elastic member is
secured to one or a plurality of points close to each other on the
pushing shaft, and moved relative to the main body with the
operation of the pushing shaft. This cannot prevent the pushing
shaft from being inclined radially with respect to the main body
around a contact position between the elastic member and the main
body in the operation of the pushing shaft.
[0011] However, if the pushing shaft is inclined with respect to
the main body, the front end of the pushing shaft is not precisely
brought into contact with the lens placed in the main body, which
may prevent the lens from being properly pushed out.
BRIEF SUMMARY OF THE INVENTION
[0012] The present invention provides an insertion device for an
intraocular lens that can prevent leakage of a liquid in the
device, and can house and store a lens as well as the liquid.
[0013] The present invention also provides an insertion device for
an intraocular lens that can restrict the amount of leakage outside
an eye of a liquid introduced into the eye through an insertion
cylinder.
[0014] The present invention further provides an insertion device
for an intraocular lens that can prevent inclination of a pushing
shaft with respect to a main body, and can properly push out a
lens.
[0015] As one aspect, the present invention provides an insertion
device for an intraocular lens which comprises a main body
including a lens housing portion that houses the lens and an
insertion cylindrical portion that feeds the lens into an eye, a
pushing shaft that moves the lens from the lens housing portion in
the front end direction to push out the lens into the eye through
the insertion cylindrical portion, and a lens holding member that
holds the lens and is placed in the lens housing portion. The lens
housing portion has a shape that receives insertion of the lens
holding member from the rear.
[0016] As another aspect, the present invention provides an
insertion device for an intraocular lens which comprises an
insertion cylinder that is inserted into an incision formed in an
eyeball and feeds the lens into the eyeball, and a pushing shaft
that pushes out the lens into the eyeball through the insertion
cylinder. The insertion cylinder is provided with a cover portion
that is brought into contact with the eyeball to cover at least
part of the incision into which the insertion cylinder is
inserted.
[0017] As yet another aspect, the present invention provides an
insertion device for an intraocular lens which comprises a main
body in which the lens is placed, a pushing shaft that pushes out
the lens from the main body into an eye, and a plurality of elastic
members that are placed between the pushing shaft and the main body
and have a distance changeable with movement of the pushing shaft
relative to the main body.
[0018] Further objects and features of the present invention will
be become more apparent from the following description of preferred
embodiments with reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1A is a top view and a side view of an insertion device
for an intraocular lens that is an embodiment of the present
invention;
[0020] FIG. 1B is a sectional view of a lens housing portion in a
main body with a nozzle of the embodiment;
[0021] FIG. 1C is a sectional view of a nozzle portion in the main
body with a nozzle of the embodiment;
[0022] FIG. 2 is a top view and a side view before assembly of the
main body with a nozzle and a pushing shaft of the embodiment;
[0023] FIG. 3 is a top view and a side view of a lens holding
member of the embodiment;
[0024] FIG. 4 is a top view and a side view showing an assembling
procedure of the insertion device of the embodiment;
[0025] FIG. 5 is a side view for illustrating a liquid introduction
method into the insertion device of the embodiment;
[0026] FIG. 6 is a perspective view for illustrating the liquid
introduction method into the insertion device of the
embodiment;
[0027] FIG. 7 is a top view and a side view for illustrating the
liquid introduction method into the insertion device of the
embodiment;
[0028] FIG. 8 is a top view and a side view for illustrating the
liquid introduction method into the insertion device of the
embodiment;
[0029] FIG. 9 is a top view and a side view for illustrating the
liquid introduction method into the insertion device of the
embodiment;
[0030] FIG. 10 is a top view and a side view for illustrating a
storage method of the insertion device of the embodiment;
[0031] FIG. 11 shows an incision formed in an eyeball;
[0032] FIG. 12 is a top view and a side view of an insertion device
of a comparative example for the embodiment;
[0033] FIG. 13 is a top view and a side view showing a state in
which a cover ring is removed from the insertion device of the
embodiment;
[0034] FIG. 14 is a sectional view showing a state of an eyeball
when a lens is inserted using the insertion device in FIG. 13;
[0035] FIG. 15 is a sectional view showing a state of an eyeball
when a lens is inserted using the insertion device of the
embodiment;
[0036] FIG. 16A is a top view and a side view of an insertion
device of a comparative example for the embodiment;
[0037] FIG. 16B is a side view of a nozzle portion of an insertion
device of an embodiment (a modified example);
[0038] FIG. 17A is a sectional view of a nozzle portion of an
insertion device of an embodiment (a modified example);
[0039] FIG. 17B is a sectional view of a nozzle portion of an
insertion device of an embodiment (a modified example);
[0040] FIG. 18 is a perspective view of a nozzle portion of an
insertion device of an embodiment (a modified example);
[0041] FIG. 19 is a side view and a bottom view of a nozzle portion
of an insertion device of an embodiment (a modified example);
[0042] FIG. 20 is a top view and a side view of a conventional type
insertion device;
[0043] FIG. 21 is a side view and a top view of an insertion device
(of a conventional type) of an embodiment;
[0044] FIG. 22 is a top view and a side view of an insertion device
(of a conventional type) of an embodiment;
[0045] FIG. 23A is a side view showing an assembly completion state
of the insertion device of the embodiment; and
[0046] FIG. 23B is a side view showing a lens pushing state of the
insertion device of the embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0047] Now, a preferred embodiment of the present invention will be
described with reference to the accompanying drawings.
[0048] FIG. 1A shows an insertion device for an intraocular lens
(hereinafter simply referred to as a lens) that is an embodiment of
the present invention. The upperside in FIG. 1A shows a top view
thereof and the lowerside shows a side view thereof. FIG. 2 shows a
state before a pushing shaft is assembled to a main body of the
insertion device. The upperside in FIG. 2 shows a top view thereof
and the lowerside shows a side view thereof.
[0049] In the description below, a nozzle side is referred to as a
front end side, a front or a front end direction, and a side
opposite to the nozzle side is referred to as a rear end side, a
rear or a rear end direction. A direction extending toward the
front end side and the rear end side is referred to as an axial
direction, and a direction perpendicular to the axial direction is
referred to as a vertical direction, a lateral (right-and-left)
direction, or a radial direction. Further, an axis parallel to the
axial direction and passing through an inner space of a main body
with a nozzle or the center of a lens is referred to as a central
axis, and a direction around the central axis is referred to as a
circumferential direction.
[0050] An insertion device 2 is basically constituted by a main
body with a nozzle (hereinafter simply referred to as a main body)
12, and a pushing shaft 16. The main body 12 includes an outer
cylindrical portion 12a as a hand-held portion having an outer
diameter suitable for holding the insertion device 2 by hand, a
lens housing portion 12b that is provided on the side closer to the
front end than the outer cylindrical portion 12a and houses a lens
holding member 28 described later, and a nozzle portion 12c as an
insertion cylindrical portion provided on the side closer to the
front end than the lens housing portion 12b. The main body 12 is an
integrally formed component (member). On the rear of the outer
cylindrical portion 12a, a flange portion 12d is formed as a
portion supported by hand when pushing the pushing shaft 16.
[0051] The main body 12 has a hollow shape, and the lens holding
member 28 and the pushing shaft 16 are inserted through a rear end
opening 12i thereof.
[0052] The outer cylindrical portion 12a has a first inner
peripheral surface 12g having a cylindrical shape from the front
end thereof to a position between the flange portion 12d and the
rear end of the outer cylindrical portion 12a. On the side closer
to the rear end than the first inner peripheral surface 12g, a
second inner peripheral surface 12m having a cylindrical shape and
a slightly smaller inner diameter than the first inner peripheral
surface 12g is formed. Further, on the side closer to the rear end
than the second inner peripheral surface 12m, a conical surface 12f
is formed which has an increasing inner diameter toward the rear
end. On the side closer to the rear end than the conical surface
12f, a third inner peripheral surface having a cylindrical shape
and a larger inner diameter than the first inner peripheral surface
12g is formed up to the rear end opening 12i.
[0053] The nozzle portion 12c has decreasing inner and outer
diameters toward the front end, and a portion from a front end
opening 12j to a predetermined length is formed to be the thinnest
portion in the nozzle portion 12c as a portion to be inserted into
an eye through an incision formed in an eyeball. On an outer
periphery of the rear end of the insertion portion, a cover ring
(an O-ring) 13 made of an elastic member such as rubber is mounted.
On the rear side of the cover ring 13 in the nozzle portion 12c, a
step 12c1 is formed having a larger outer diameter than the
insertion portion for preventing rearward movement of the cover
ring 13. The function of the cover ring 13 will be described
later.
[0054] The lens housing portion 12b basically has a section of a
hollow flat plate shape having a vertical dimension smaller than a
lateral dimension in axial view. A rear portion in a lower surface
of the lens housing portion 12b near a boundary with the outer
cylindrical portion 12a has a semi-conical shape having an
increasing diameter toward the rear for reinforcement. The lens
housing portion 12b is inserted through the rear end opening 12i,
and thus a connection between the outer cylindrical portion 12a and
an inner surface of the lens housing portion 12b is tapered to
provide a guide configuration and facilitate insertion when the
holding member 28 is inserted.
[0055] The lens housing portion 12b can receive the insertion of
the lens holding member 28 from the rear end thereof, and has an
inner surface shape that can stably hold the inserted lens holding
member 28.
[0056] As shown in FIGS. 1B and 1C showing sections perpendicular
to an axis of the lens housing portion 12b and the nozzle portion
12c, respectively, peripheral walls 12b1 and 12c4 from the lens
housing portion 12b to the nozzle portion 12c are formed as
integral walls without an opening and a gap. In other words, four
side (upper, lower, right and left) walls surrounding an inner
space are circumferentially connected, and integrally formed
without an opening such as a hole and a dividable portion or an
openable and closable portion in which a gap is created in an
assembled portion.
[0057] In the embodiment, the case is described where the main body
12 is produced as an integrally formed component (member) so that
at least the peripheral walls 12b1 and 12c4 from the lens housing
portion 12b to the nozzle portion 12c have no opening or gap.
However, an alternative embodiment of the present invention is not
limited to this case. For example, it is allowed that components
divided into two upper and lower portions from the front end to the
rear end may be joined by thermal welding or bonding and integrated
to constitute the main body 12, and the main body 12 is thereby
made as an integral component (member) without a gap at least in
peripheral walls of the lens housing portion 12b and nozzle portion
12c after completion of the main body 12 (before insertion of the
lens holding member 28). It is also allowed that the lens housing
portion 12b, the nozzle portion 12c and the outer cylindrical
portion 12a that are formed in a divided manner are joined by
thermal welding or bonding, and the main body 12 is thereby made as
an integral component without a gap at least in peripheral walls
from the lens housing portion 12b to the nozzle portion 12c after
completion of the main body 12 (before insertion of the lens
holding member 28).
[0058] As shown by a dotted line in the top view in FIG. 1A, a
small hole 12h is formed in a peripheral wall near the front end of
the outer cylindrical portion 12a. This hole 12h is naturally
formed for placing a member that supports a die for forming the
inner surface of the main body 12 in production of the main body
12, that is, when the main body 12 is integrally formed of
resin.
[0059] In the embodiment, in order to completely cover the hole
12h, an O-ring 32 made of an elastic member such as rubber is
mounted to the outer periphery of the outer cylindrical portion
12a. Thus, the main body 12 has no opening other than the rear end
opening 12i in the outer cylindrical portion 12a and the front end
opening 12j in the nozzle portion 12c. Thus, as described later,
the rear end opening 12i is covered with a seal cap 14 provided on
the pushing shaft 16 without a gap, and the front end opening 12j
is covered with a cap 34 described later without a gap, thereby
allowing a sealed space to be formed in the main body 12 that can
house a liquid such as a viscoelastic material or physiologic
saline without leakage, and store the liquid with the lens 1.
[0060] A mounting surface for the O-ring 32 on the outer peripheral
surface of the outer cylindrical portion 12a has a diameter smaller
than those on the sides closer to the front and rear ends. This
prevents axial movement of the O-ring 32 on the outer cylindrical
portion 12a. The O-ring 32 is provided on a position often touched
by hand of an operator holding the insertion device 2. Thus, the
O-ring 32 has the function of covering the hole 12h as well as the
function of preventing slip of the hand holding the insertion
device 2. If not covering the hole 12h does not directly influence
the flow of the liquid, covering of the hole 12h is not necessarily
required.
[0061] The lens holding member 28 includes a first holding member
28A that supports the lens 1 from below, and a second holding
member 28B that retains from above the lens 1 in combination with
the first holding member 28A.
[0062] First, the configuration of the lens 1 held by the lens
holding portion will be described. The lens 1 has a circular shape
in top view, and includes an optical portion 1a having the function
of a lens and support portions 1b extending from the front end and
the rear end of the optical portion 1a.
[0063] The support portion 1b is a wire-like portion that
elastically supports the optical portion 1a in the eye after the
lens 1 is inserted into the eye.
[0064] A ring-shaped marginal (peripheral) portion 1c having
parallel upper and lower surfaces is formed around the optical
portion 1a. The marginal portion 1c is hereinafter referred to as
the lens marginal portion 1c.
[0065] As shown in FIG. 3A, the first holding member 28A is formed
laterally symmetrically with respect to the central axis CA passing
through the center O of the optical portion 1a of the lens 1 except
part thereof. Support surfaces 28a are formed on the right and left
in the lower portion of the first holding member 28A. The support
surfaces 28a are formed as inclined surfaces whose inner portion is
lower than its outer portion in the lateral direction.
[0066] In a top view in FIG. 3, a position in the front end
direction from the center O of the optical portion 1a in the lens
marginal portion 1c (a position on the central axis CA) is a
0.degree. position. The right and left support surfaces 28a contact
arcuate regions between positions retracted by a circumferential
angle of 60.degree. to both circumferential sides (60.degree.
positions, other positions are hereinafter referred to as the same)
from the 0.degree. position in the lens marginal portion 1c, and
90.degree. positions retracted by a circumferential angle of
90.degree., and support the arcuate regions from below.
[0067] On the right and left in the axial middle of the first
holding member 28A, support protrusions 28b are formed which
support arcuate regions between 135.degree. positions to
165.degree. positions which are regions closer to the rear than the
arcuate regions supported by the support surfaces 28a in the lens
marginal portion 1c. A space through which the pushing shaft 16 (a
pushing shaft portion 16c) passes is provided between the support
protrusions 28b. Since the space has only a 30.degree. angle range,
it may be considered that the support protrusions 28b support an
arcuate region of a 90.degree. angle range around a 180.degree.
position in the lens marginal portion 1c. Specifically, the first
lens support member 28A supports the lens marginal portion 1c at
three points at 120.degree. intervals including the right and left
60.degree. positions and the 180.degree. position.
[0068] Each of the support protrusions 28b has a horizontal surface
on which the lens marginal portion 1c is placed and a vertical
surface that contacts or is brought close to an outer peripheral
end surface of the lens marginal portion 1c on the rear side of the
horizontal surface, supports the lens marginal portion 1c from
below, and prevents rearward movement of the lens 1.
[0069] Further, on the right and left on the front end side of the
first holding member 28A, a vertical surface 28e is formed that
contacts or is brought close to the 60.degree. position in the
outer peripheral end surface of the lens marginal portion 1c. The
vertical surface 28e prevents movement of the optical portion 1a in
the front end direction in a state before pushing out the lens
1.
[0070] In an upper portion at the front end of the first holding
member 28A, an arm 28c is formed extending from one side to the
other side in the lateral direction (from the lower side to the
upper side in the top view in FIG. 3), and at the tip of the arm
28c, a protrusion 28d that supports from below the front side
support portion 1b is formed to extend in the front end
direction.
[0071] On the rear of the first holding member 28A, an inclined
surface 28f that supports from below the rear side support portion
1b is formed so that its portion closer to the rear end is placed
in a higher position.
[0072] Next, the configuration of the second holding member 28B
will be described. The second holding member 28B is placed above
the first holding member 28A. The first and second holding members
28A and 28B are inserted into the lens housing portion 12b while
holding the lens 1, and held between a ceiling surface and a bottom
surface of the lens housing portion 12b without displacement.
[0073] The second holding member 28B is formed laterally
symmetrically with respect to the central axis CA, though not
shown. On the right and left in a lower surface of the second
holding member 28B, retaining protrusions 28g are formed that
contact or are brought close to arcuate regions from the 90.degree.
positions to 120.degree. positions and arcuate regions from the
135.degree. positions to the 165.degree. positions on the right and
left in the lens marginal portion 1c. A space through which the
pushing shaft 16 (the pushing shaft portion 16c) passes is provided
between the right and left retaining protrusions 28g with the
180.degree. position therebetween.
[0074] A portion on the front side of the retaining protrusion 28g
retains from above an arcuate region closer to the rear than the
arcuate region that contacts the support surface 28a provided in
the first holding member 28A in the lens marginal portion 1c, and a
portion on the rear side of the retaining protrusion 28g retains
from above the arcuate region supported from below by the support
protrusion 28b provided in the first holding member 28A in the lens
marginal portion 1c.
[0075] As shown in a side view in FIG. 3, the second holding member
28B is assembled to the upper side of the first holding member 28A,
and thus the arcuate regions from the 60.degree. positions to the
90.degree. positions in the lens marginal portion 1c are supported
from below by the support surfaces 28a of the first holding member
28A, and the arcuate regions from the 90.degree. positions to the
120.degree. positions are retained from above by the front side
portions of the retaining protrusions 28g in the second holding
member 28B. The arcuate regions from the 135.degree. positions to
the 165.degree. positions are vertically held by the horizontal
surfaces of the support protrusions 28b provided in the first
holding member 28A and the rear side portions of the retaining
protrusions 28g provided in the second holding member 28B
therebetween. With such a holding structure, the lens 1 is
supported in a state in which the optical portion 1a of the lens 1
is held in a horizontal state and a stress by its own weight or an
external force is not substantially applied.
[0076] The state in which a stress is not substantially applied
denotes a state in which no stress is applied to the optical
portion at all as well as a state in which a minute stress is
applied so that a deformation influencing the optical function of
the optical portion 1a after insertion of the lens 1 into the eye
does not occur even if the lens 1 is held and stored for a long
time. In other words, the state denotes a state in which a stress
or a deformation influencing the optical function of the optical
portion 1a does not occur.
[0077] The vertical surfaces 28e that contact the 60.degree.
positions in the outer peripheral end surface of the lens marginal
portion 1c and the vertical surfaces of the support protrusions 28b
that contact the regions from the 135.degree. positions to the
165.degree. positions prevent displacement of the lens 1 in the
front end direction and the rear end direction. Further, the front
end side of the lens marginal portion 1c is opened by 120.degree.
by providing the right and left vertical surfaces 28e in the
60.degree. positions. This allows the lens 1 to be smoothly moved
from the lens holding member 28 in the front end direction in
pushing out the lens 1.
[0078] On the side closer to the rear than the portions retaining
the lens marginal portion 1c of the retaining protrusions 28g in
the second holding member 28B, inclined portions are formed that
extend in parallel with the inclined surface 28f in the first
holding member 28A and hold the rear side support portion 1b
together with the inclined surface 28f.
[0079] Further, the vertical surfaces 28e in the first holding
member 28A are formed such that one of them extends in the front
end direction along the outer edge of the front side support
portion 1b and the other extends in the same shape as the one. The
contact of the one of the vertical surfaces 28e with the front side
support portion 1b and the holding of the rear side support portion
1b between the inclined surface 28f and the inclined portions of
the retaining protrusions 28g prevent rotation of the lens 1.
[0080] In an alternative embodiment of the present invention, the
configuration of the lens holding member is not limited to the
above case, and any lens holding member may be allowed that can
hold a lens in a state in which a stress is not substantially
applied to an optical portion. The lens is not limited to one
having an optical portion and a wire-like support portion, but may
have an optical portion and a support portion having a flat plate
shape.
[0081] FIG. 20 shows a conventional type insertion device. The
upperside in FIG. 20 shows a top view thereof and the lowerside
shows a side view thereof. A main body 112 of the insertion device
102 is constituted by a plurality of components including an outer
cylinder 112a, a lens holding member 112b assembled to the front
end of the outer cylinder 112a, and a nozzle 112c assembled to the
lens holding member 112b so as to extend from a lower surface of
the lens holding member 112b to the front end. An opening 112h is
formed in an upper surface of the lens holding member 112b, and a
lens 1 is set in the lens holding member 112b through the opening
112h. A cover member 124 is mounted to the lens holding member 112b
so as to cover the opening 112h.
[0082] In this conventional type insertion device 102, gaps are
created at assembled portions of the plurality of components. In
the lens holding member 112b corresponding to the lens housing
portion 12b of the embodiment, the opening 112h through which the
lens 1 is set is formed, and a gap leading to the outside from the
opening 112h is created even if the opening 112h is covered with
the cover member 124.
[0083] Thus, when a liquid such as a viscoelastic material or
physiologic saline is introduced into the main body 112, the liquid
leaks from the gap. Particularly, physiologic saline having a lower
viscosity than the viscoelastic material leaks immediately after
being introduced, and it is difficult to maintain the viscoelastic
material in an amount required for an operation in the main body
112. Though the amount of leakage of the viscoelastic material is
small because of its viscosity, the leakage may make the insertion
device 102 slippery and is unpreferable.
[0084] As shown in FIGS. 1A and 2, the pushing shaft 16 has a D-cut
shaft portion 16a, a cylindrical portion 16b, and a pushing shaft
portion 16c in order from the rear end side thereof. The D-cut
shaft portion 16a has a so-called D-cut shape having a section in
axial view of a non-rotationally symmetric shape with a circular
upper portion cut to be flat. On the D-cut shaft portion 16a, an
O-ring (a second elastic member) 43 made of an elastic member such
as rubber is mounted axially movably relative to the D-cut shaft
portion 16a.
[0085] The cylindrical portion 16b has the same or a smaller outer
diameter as or than a cylindrical portion of the D-cut shaft
portion 16a, and the seal cap (a first elastic member) 14 made of
an elastic member such as rubber is mounted to the outer periphery
of the cylindrical portion 16b. The seal cap 14 has a ring portion
14a mounted on the cylindrical portion 16b, and a conical portion
14b having a decreasing diameter from the front end of the ring
portion 14a toward the front end. A hole through which the pushing
shaft portion 16c passes is formed in the front end of the conical
portion 14b.
[0086] The pushing shaft portion 16c has a small outer diameter
that can pass through an inner passage of the nozzle portion 12c,
and has, at the front end thereof, a lens grip portion 16d
vertically bifurcated. The lens grip portion 16d vertically holds
the rear end of the optical portion 1a of the lens 1 held by the
lens holding member 28 in the lens housing portion 12b. This allows
the lens 1 to be reliably pushed by the pushing shaft 16 in the
front end direction.
[0087] In the conventional type insertion device such as the
insertion device in FIG. 20, a rubber ring is mounted on an outer
periphery of a pushing shaft, and the rubber ring slides relative
to an inner surface of the main body with movement of the pushing
shaft. However, the rubber ring is intended for providing proper
sliding feeling (operation resistance) to an operation of the
pushing shaft, and has no sealing function of preventing leakage of
a liquid housed in the main body.
[0088] On the other hand, the seal cap 14 of the embodiment mainly
has the sealing function, and is brought into press contact with
the inner peripheral surface of the main body 12 by a press-contact
force for achieving the sealing function, thereby also providing
sliding feeling.
[0089] In the embodiment, in order to achieve the sealing function,
an axial width of the ring portion 14a of the seal cap 14 is set to
2 mm or more, and further, on the front end side of the ring
portion 14a, the conical portion 14b is provided for preventing the
liquid from leaking from the gap between the ring portion 14a and
the cylindrical portion 16b of the pushing shaft 16. Further, in
the embodiment, in a state before pushing of the pushing shaft 16
(an assembly completion state or a storage state) in FIG. 1A, the
inner diameter of the second inner peripheral surface 12m with
which the ring portion 14a of the seal cap 14 is brought into press
contact in the inner peripheral surface of the main body 12 is set
to be smaller than the inner diameter of the first inner peripheral
surface 12g formed on the side closer to the front end than the
second inner peripheral surface 12m. The inner diameter of the
second inner peripheral surface 12m is set to be small to increase
the press-contact force with the ring portion 14a of the seal cap
14, thereby increasing the sealing function. Specifically, as
described later, the insertion device 2 can be stored so that the
liquid introduced into the main body 12 does not leak. The inner
peripheral surfaces 12g and 12m of the main body are preferably
circular.
[0090] The outer peripheral surface of the ring portion 14a of the
seal cap 14 may be a simple cylindrical surface, but in order to
increase the sealing function, the outer peripheral surface may
have a ring shape with a semicircular section or have a plurality
of ring shapes in the axial direction.
[0091] As described above, the lens grip portion 16d that holds the
upper and lower surfaces of the optical portion 1a of the lens 1 is
provided in the front end of the pushing shaft 16, and when the
pushing shaft 16 is pushed in a state in which the pushing shaft 16
is rotated with respect to the main body 12, the lens grip portion
16d cannot properly push the optical portion 1a. Thus, particularly
before pushing of the pushing shaft 16, the rotation of the pushing
shaft 16 with respect to the main body 12 needs to be prevented.
Further, if the pushing shaft 16 is removed from the main body 12
before pushing or after the start of the pushing, reinsertion
thereafter of the pushing shaft 16 into the main body 12 is not
always properly performed, and thus the removal needs to be
prevented. In these views, the function required for the pushing
shaft 16 of the insertion device 2 is different from a simple
sealing function required for a general syringe.
[0092] Thus, in the embodiment, as described above, the inner
diameter of the second inner peripheral surface 12m is set to be
small, and using an increase thereby in the press-contact force
between the ring portion 14a of the seal cap 14 and the second
inner peripheral surface 12m, that is, a friction force, the
configuration is achieved in which the pushing shaft 16 is hardly
rotated with respect to the main body 12 or removed from the main
body 12.
[0093] In the embodiment, the case has been described where the
rotation of the pushing shaft 16 with respect to the main body 12
or the removal thereof from the main body 12 is restricted using
friction caused by press contact between the seal cap 14 and the
main body 12, but the rotation or the removal of the pushing shaft
may be restricted by other methods. For example, it is possible
that the main body 12 has an inner peripheral shape similar to an
outer peripheral shape of the D-cut shaft portion 16a of the
pushing shaft 16, and flat surface portions thereof contact each
other to prevent rotation of the pushing shaft 16 with respect to
the main body 12. A step formed between the D-cut shaft portion 16a
and the cylindrical portion 16b (the seal cap 14) may contact a
contact surface formed in the main body 12 to prevent removal of
the pushing shaft 16 from the main body 12.
[0094] The relationship between the seal cap 14 and the inner
peripheral surface of the main body 12 in the embodiment may be
applied to the conventional type insertion device as shown in FIG.
21. FIG. 21 (the upperside shows a side view and the lowerside
shows a top view) shows the configuration in which a double seal
ring 44 corresponding to the seal cap 14 in the embodiment is
provided in the pushing shaft 116, and the inner diameter of a
portion (seal portion) with which the double seal ring 44 is
brought into press contact in the inner peripheral surface of the
rear end side portion of the main body 112 is smaller than that of
an inner peripheral surface of a portion closer to the front end
than the above seal portion.
[0095] An assembling procedure of the insertion device 2 thus
configured will be described with reference to FIG. 4 (the
upperside shows a top view and the lowerside shows a side view).
First, the lens 1 is held by the lens holding member 28. Then, the
O-ring 32 and the cover ring 13 are mounted to the outer
peripheries of the outer cylindrical portion 12a and the nozzle
portion 12c, respectively, of the main body 12. When the hole 12h
is used for introducing a liquid into the main body 12 after the
assembly, it is recommended to displace the O-ring 32 to a position
where it does not cover the hole 12h.
[0096] Then, the lens holding member 28 is inserted from the rear
into the lens housing portion 12b through the rear end opening 12i.
The lens holding member 28 inserted into the lens housing portion
12b is held by contact of the outer surface thereof with the inner
surface of the lens housing portion 12b substantially without
circumferential and axial backlash.
[0097] Next, the pushing shaft 16 to which the O-ring 43 and the
seal cap 14 are mounted is inserted into the main body 12 through
the rear end opening 12i. The pushing shaft 16 is inserted until
the lens grip portion 16d reaches the immediate rear of the lens 1
in the lens housing portion 12b. At this time, the outer peripheral
surface of the ring portion 14a of the seal cap 14 is brought into
press contact with the second inner peripheral surface 12m of the
outer cylindrical portion 12a to perform the sealing function and
the rotation and removal preventing function described above.
[0098] The O-ring 43 is also caused to contact the conical surface
12f formed in the inner periphery of the outer cylindrical portion
12a. The function of the O-ring 43 will be described later.
[0099] Into the insertion device 2 assembled as described above, a
liquid is introduced such as a viscoelastic material such as sodium
hyaluronate or physiologic saline (including one in which drug is
dissolved) as described later. A liquid introduction method will be
described below. A liquid to be introduced includes hydrophilic
(water-soluble) polymer liquid besides sodium hyaluronate or
physiologic saline. For example, synthetic polymer includes
polyethylene glycol (PEG), polypropylene glycol (PPG), sodium
polyacrylate (PAA), polyacrylamide (PAAm), sodium polystyrene
sulfonate (PSSNa), polyvinylpyrrolidone (PVP), polyvinyl alcohol
(PVA), polyethyleneimine (PEI), carboxymethylcellulose (CMC),
dextran sodium sulfate, hydroxyethyl starch (HEPES), and
polyphosphoric acid.
[0100] Natural polymer includes hyaluronate and/or sodium
hyaluronate (HA), sodium alginate, dextran, dextrin, heparin,
chitosan, and sodium chondroitin sulfate as polysaccharide, and
polypeptide and polynucleic acid as other than polysaccharide.
[0101] Among them, polysaccharide is preferably used in view of
biocompatibility or the diversity of molecular weight obtained.
[0102] Next, several methods of introducing a liquid such as
physiologic saline having a lower viscosity than the viscoelastic
material into the main body 12 will be described.
[0103] FIG. 5 shows a first liquid introduction method. The liquid
in a syringe 35 is introduced through an injection needle inserted
into the front end opening 12j of the nozzle portion 12c. At this
time, it is recommended to mount to the nozzle portion 12c a guide
member 30 that guides the injection needle to the front end opening
12j so as to facilitate insertion of the injection needle into the
front end opening 12j. At this time, the O-ring 32 is placed to
cover the hole 12h formed in the main body 12.
[0104] The liquid introduced into the main body 12 hardly leaks
even if the front end opening 12j is directed downward because the
main body 12 has no opening leading to the outside other than the
front end opening 12j. This also applies to liquid introduction
methods described below.
[0105] FIG. 6 shows a second liquid introduction method. The liquid
is placed in a container 36 such as a sterile beaker, and the
pushing shaft 16 is drawn rearward in a state in which the nozzle
portion 12c is inserted in the liquid. The main body 12 is sealed
except the front end opening 12j, thereby allowing the liquid to be
introduced into the main body 12 similarly to the syringe.
[0106] The lens grip portion 16d of the pushing shaft 16 needs to
be inserted until it reaches the immediate rear of the lens 1 in
the lens housing portion 12, and can reliably push the lens optical
portion according to the position relationship thereof. Thus, in
order to introduce the liquid similarly to the syringe, the
configuration is adopted in which two pushing shafts are provided,
a hole is formed in one pushing shaft with a seal cap 14 having no
lens grip portion 16d, and the other pushing shaft 16 having a lens
grip portion 16d can be assembled in the hole. Then, the pushing
shaft having the seal cap 14 is drawn rearward in a state in which
the pushing shaft 16 having the lens grip portion 16d is fixed in
the position. This allows the liquid to be introduced similarly to
the syringe in a state in which the lens grip portion 16d of the
pushing shaft 16 is fixed in the position on the immediate rear of
the lens housing portion 12.
[0107] FIG. 7 shows a third liquid introduction method. The O-ring
32 is displaced from the hole 12h formed in the main body 12, the
needle of the syringe 35 or a liquid supply device is inserted into
the hole 12h to introduce the liquid into the main body 12. Then,
the O-ring 32 is moved so as to cover the hole 12h. The outer
peripheral surface having the hole 12h is tapered to function as a
guide in insertion so as to facilitate insertion of the front end
of the needle or the liquid supply device, which further increases
operability.
[0108] FIG. 8 shows a fourth liquid introduction method. In this
method, a plug (a lid) 33 made of an elastic member fitted in the
hole 12h is used in place of the O-ring 32. The needle of the
syringe 35 is inserted into the plug 33 to introduce the liquid in
the syringe into the main body 12. The plug 33 can prevent leakage
of the liquid because a hole after removal of the needle is closed
by elasticity thereof. In order to prevent the plug 33 from being
removed from the hole 12h, it is recommended to devise the shape of
the plug 33. For example, a portion of the plug 33 fitted in the
hole 12h preferably has an increasing thickness toward the bottom.
The plug 33 may be bonded to the main body 12.
[0109] FIG. 9 shows a fifth liquid introduction method. Similarly
to the third method, the needle of the syringe 35 or the liquid
supply device is inserted into the hole 12h to introduce the liquid
into the main body 12. Then, a lid (a plug) 33' is mounted to the
main body 12 so as to cover the hole 12h to prevent the liquid from
leaking from the hole 12h. In order to prevent the lid 33' from
being removed from the hole 12h, it is recommended to devise the
shape of the lid 33'. For example, a portion of the lid 33' fitted
in the hole 12h preferably has an increasing thickness toward the
bottom. The lid 33' may be bonded to the main body 12.
[0110] If use of the insertion device without the plug 33 or the
O-ring 32 does not directly influence the flow of the liquid, the
use of the plug 33 or the O-ring 32 is not necessarily
required.
[0111] According to the liquid introduction method described above,
the liquid can be easily introduced into the main body 12
immediately before an operation or before factory shipment of the
insertion device. When the liquid is introduced before factory
shipment and then shipped, transported, and stored, the nozzle
portion 12c is preferably covered with the cap 34 in FIG. 10 in
order to prevent leakage of the liquid outside during the shipment,
transportation and storage.
[0112] The cap 34 has no opening in the front end and the
peripheral wall portion, and has an opening in the rear end. A seal
ring 27 made of an elastic member is mounted to the inside of the
rear end. The cap 34 is mounted so that the seal ring 27 is brought
into tight contact with the outer peripheral surface of the nozzle
portion 12c (or the lens housing portion 12b) to form a closed
space around the nozzle portion 12c. Thus, even if the liquid leaks
from the front end opening 12j into the cap 34, the liquid does not
leak outside. This also prevents vaporization of the liquid and
damage to the nozzle portion 12c. Thus, the lens 1 as well as the
liquid can be held in the insertion device 2 and stored for a long
time.
[0113] In the case of an operation, the cap 34 is removed if
mounted, and the front end (a portion to be inserted into an eye)
of the nozzle portion 12c is inserted into the eye through an
incision formed in an eyeball. Then, the pushing shaft 16 is pushed
into the main body 12. Thus, the liquid in the main body 12 starts
to be introduced into the eye through the front end opening 12j of
the nozzle portion 12c, and the lens 1 with the optical portion 1a
held by the lens grip portion 16d starts to be moved from on the
lens holding member 28 in the front end direction. The lens 1 is
folded and deformed into a small shape with movement in the nozzle
portion 12c, and pushed into the eye through the front end opening
12j.
[0114] It can be expected that the liquid is introduced into the
eye from the nozzle portion 12c to increase ocular tension and
inflate the anterior chamber, thereby forming an insertion space
for the lens 1. As shown in FIG. 11, however, in a state in which
the nozzle portion 12c is inserted into an incision 15a in an
eyeball 15, the incision 15a has a larger area than the nozzle
portion 12c, thereby creating a gap (a region outside the nozzle
portion 12c) 20 between the periphery of the incision 15a and the
outer peripheral surface of the nozzle portion 12c. Thus, the
liquid once introduced into the eye leaks from the gap 20, and in
particular, when the amount of liquid introduced into the main body
12 is relatively small (for example, about 0.5 to 2.5 ml), the
ocular tension cannot be increased and the anterior chamber cannot
be sufficiently inflated.
[0115] Thus, in the embodiment, the cover ring 13 provided near the
front end of the nozzle portion 12c is pressed against the eyeball
15 to cover the gap 20 in the incision 15a. In this case, the cover
ring 13 may completely or partly cover the gap 20. This can
restrict (prevent or reduce the amount of) the flow of the liquid
from the gap 20, and even if the amount of the liquid introduced
into the main body 12 is relatively small, the ocular tension can
be reliably increased to sufficiently inflate the anterior chamber.
When the ocular tension becomes too high, the insertion device 2 is
displaced rearward so as to separate the cover ring 13 from the
eyeball 15, and the liquid flows out of the gap 20 of original
size, thereby reducing the ocular tension.
[0116] In this manner, according to the embodiment, the lens 1 can
be inserted into the eye and also the ocular tension can be
controlled simply by an operation on hand of the operator.
[0117] In the embodiment, the case has been described where the
cover ring 13 as a separate member from the nozzle portion 12c is
used for covering the gap 20 in the incision 15a in the eyeball 15,
but a ring-shaped portion having the same function as the cover
ring 13 may be formed integrally with the nozzle portion 12c.
[0118] Now, the results of experiments on the functions of the
cover ring 13 and a cover-ring-shaped portion having the same
function and the results of experiments on optimization of the
front end shape of the nozzle portion 12c will be shown.
[0119] Experiment 1: First, as shown in FIG. 12 (the upperside
shows a top view and the lowerside shows a side view), a device 19
for supplying a liquid such as physiologic saline was connected to
an insertion device 2' via a tube 18 and an experiment was
conducted. At this time, the insertion device 21 did not have a
cover ring 13 or a configuration corresponding thereto. A flow path
through which the liquid passes was provided in a pushing shaft
16', and the tube 18 was connected to the pushing shaft 16'.
[0120] When the liquid was continuously introduced into the eyeball
from the liquid supply device 19 via the insertion device 2' (a
nozzle portion 12c), it was confirmed that ocular tension increased
and the anterior chamber was filled with the liquid, and the
posterior capsule of the crystalline lens moved toward the vitreous
body (the anterior chamber was inflated). It was found that when
the liquid of a predetermined flow rate can be continuously
supplied from the liquid supply device 19 to the eyeball, the cover
ring 13 or the configuration corresponding thereto needs not to be
provided in the nozzle portion 12c.
[0121] Experiment 2: An experiment was conducted using an insertion
device 2 in which a liquid of 25 ml was previously introduced into
a main body 12 as shown in FIG. 13. In this experiment, a nozzle
portion 12c did not have a cover ring 13 or a configuration
corresponding thereto. In this case, even if a pushing shaft 16 was
pushed to introduce most of the liquid in the main body 12 into the
eye, ocular tension hardly increased from ocular tension when an
incision was formed, and the posterior capsule of the crystalline
lens did not move toward the vitreous body. The reason that the
ocular tension did not increase was studied and found. It was
because the incision was linearly formed by a knife, and the
three-dimensional nozzle portion 12c was inserted into the incision
to form a gap 20 in FIG. 11, and a liquid L leaked from the gap 20
as shown in FIG. 14.
[0122] Experiment 3: A cover ring 13 was mounted to the nozzle
portion 12c of the insertion device 2 used in Experiment 2, and the
cover ring 13 was brought into tight contact with a portion near
the incision 15a in the eyeball 15 as shown in FIG. 15, and an
experiment similar to Experiment 2 was conducted. In this case,
ocular tension increased and the posterior capsule of the
crystalline lens moved toward the vitreous body. It was confirmed
that this was because a gap 20 is created outside the nozzle
portion 12c in the incision 15a, but the cover ring 13 is brought
into tight contact with around the incision 15a in the eyeball 15,
and thus even if the liquid flows out of the gap 20, a seal by the
cover ring 13 prevents the liquid from leaking outside. In
particular, the cover ring 13 has a circular section, and thus the
cover ring 13 is brought into ring-shaped line contact around the
incision 15a in the eyeball 15. Thus, it can be considered that a
sealing effect was able to be obtained more easily and reliably
than the case of a seal by surface contact.
[0123] As described above, a step 12c1 was provided in the nozzle
portion 12c to prevent the cover ring 13 from moving rearward on
the nozzle portion 12c. Also, a tilt of the cover ring 13 on the
nozzle portion 12c was allowed to stably maintain a tight contact
state of the cover ring 13 on the eyeball 15.
[0124] Experiment 4: As shown in FIG. 16A, a ring-shaped portion
12c2 having substantially the same shape as the cover ring 13 was
formed integrally with the nozzle portion 12c, and an experiment
similar to Experiments 2 and 3 was conducted. In this case, the
ring-shaped portion 12c2 had little flexibility. Thus, the
ring-shaped portion 12c2 was able to be partly brought into tight
contact with the eyeball 15, but other portions was not able to be
brought into tight contact with the eyeball 15, and the liquid
leaked outside from a gap between the eyeball 15 and the
ring-shaped portion 12c2. Thus, ocular tension hardly
increased.
[0125] As shown in FIG. 16B, however, it was found that a
ring-shaped portion (a cover-ring-shaped portion) 12c3 is formed to
have a thickness of about 0.3 mm and have flexibility, and thus the
entire circumference of the cover ring-shaped portion 12c3 can be
brought into tight contact with the eyeball 15, and a sealing
effect equal to the seal ring 13 can be obtained.
[0126] Experiment 5: FIGS. 17A and 17B show the shape of a section
of a nozzle portion 12c of an insertion device used in this
experiment. As shown in FIG. 11, when the nozzle portion 12c having
a circular section or an oval section is inserted into the incision
15a, the incision 15a is opened to a substantially rhombic shape.
Then, gaps 20 each having a substantially triangular shape are
formed between the nozzle portion 12c and the edges of the incision
15a.
[0127] Thus, in this experiment, nozzle portions 12c' and 12c''
having protruding incision covering shapes 12c4 and 12c5 that can
substantially fill the gaps 20 were formed, and an experiment
similar to Experiments 2 to 4 was conducted. In this case, the gaps
created between the nozzle portions 12c' and 12c'' and the edges of
the incision 15a were reduced in size or eliminated, and thus the
leakage of the liquid from the eyeball 15 was reduced or prevented
to increase the ocular tension.
[0128] In this manner, it was found that the nozzle portion itself
is formed to have the shape that can fill the gaps 20 to obtain a
sealing effect equal to the case where the cover ring 13 or the
cover-ring-shaped portion 12c3 is provided in the nozzle portion
12c.
[0129] It is considered that a higher sealing effect can be
obtained by providing the cover ring 13 or the cover-ring-shaped
portion 12c3 in the nozzle portion having the protruding incision
covering shapes 12c4 and 12c5.
[0130] Experiment 6: As in Experiments 3 and 4, providing the cover
ring 13 or the cover-ring-shaped portion 12c3 in the nozzle portion
12c can increase ocular tension. It is more preferable to provide
the configuration for adjusting ocular tension to proper one when
the ocular tension becomes too high to the contrary.
[0131] In this experiment, as shown in FIG. 18, an opening such as
a hole 37 or a slit 38 was provided on the front end side of the
nozzle portion 12c from the cover ring 13 or the cover-ring-shaped
portion 12c3. Also, an inclined portion 39 was formed in the front
end of the nozzle portion 12c.
[0132] When the ocular tension becomes too high, the insertion
device 2 is slightly drawn from the eyeball so that part of the
hole 37, the slit 38 or the inclined portion 39 is exposed to the
outside of the eye, and thus a liquid flowing from the main body 12
to the front end opening 12i of the nozzle portion 12c or a liquid
in the eye is ejected to the outside of the eye through the hole 37
or the like. This facilitates adjustment of the ocular tension.
[0133] For increasing the ocular tension again because it becomes
too low, the hole 37 or the like may be placed in the eye to bring
the cover ring 13 or the cover-ring-shaped portion 12c3 into tight
contact with the eyeball.
[0134] Experiment 7: When the nozzle portion 12c is inserted into a
linear incision, ocular tension is still low and the incision is
not opened. Thus, it is difficult to insert the nozzle portion 12c
even if the front end thereof has an inclined shape to some extent.
On the other hand, merely forming the front end of the nozzle
portion 12c to have an excessively inclined shape for facilitating
insertion of the nozzle portion 12c into the linear incision
increases movement resistance (friction resistance) of the lens 1
in the nozzle portion 12c, and places an excessive load on the lens
1.
[0135] Thus, an experiment was conducted by changing the front end
shape of the nozzle portion 12c in various manners. One of the
shape is as shown in FIG. 19 (the upperside is a side view and the
lowerside is a bottom view). In FIG. 19, an inclined portion 41 was
first provided on the lower side of the front end of the nozzle
portion 12c. A peripheral wall from the front end of the inclined
portion 41 (the front end of the nozzle portion 12c) to the rear
end of the inclined portion 41 is hereinafter referred to as a
front end peripheral wall T.
[0136] The front end peripheral wall T was formed over the entire
circumference to be a tapered surface 40 inclined by an angle of
10.degree. or more in a tapering direction with respect to a
peripheral wall closer to the front end than the peripheral wall T.
This facilitated insertion of the nozzle portion 12c into an
incision in an eyeball with low ocular tension.
[0137] On the other hand, when the inclination angle of the front
end peripheral wall was 9.degree. or less with respect to the
peripheral wall closer to the rear than the front end peripheral
wall, insertion of the nozzle portion 12c into the incision was
difficult.
[0138] When the tapered surface 40 having an angle of 10.degree. or
more is formed from a position closer to the rear than the rear end
of the inclined portion 41, the taper excessively reduces a space
in the nozzle portion to excessively increase friction resistance
when the lens 1 passes through the space in the nozzle portion.
[0139] In this respect, as in this experiment, the tapered surface
40 is formed on the front end side from the rear end of the
inclined portion 41 to prevent an increase in friction resistance
when the lens 1 passes through the inside of the nozzle portion
12c. Further, when the lens 1 passes the rear end of the inclined
portion 41, deformation of the lens 1 is released and a stress
generated in the lens 1 by the deformation is released, thereby
reducing friction resistance. This facilitated insertion of the
nozzle portion 12c into the incision in the eyeball with low ocular
tension, and achieved the nozzle portion 12c with a light load on
the lens 1.
[0140] Experiment 8: The configuration in which the cover ring 13
or the cover-ring-shaped portion 12c3 described in Experiments 3
and 4, or the protruding incision covering shapes 12c4 and 12c5 is
provided in the nozzle portion may be applied not only to the
insertion device of the embodiment but to the conventional type
insertion device as shown in FIG. 20. FIG. 22 shows an insertion
device in FIG. 20 provided with a cover ring 13 in a nozzle
portion. In this experiment, a viscoelastic material was used as a
lubricant.
[0141] The cover ring 13 was provided in the nozzle portion 112c of
the insertion device 102 to bring the cover ring 13 into tight
contact with the eyeball 15 similarly to Experiments 3 and 4. Thus,
the amount of flow of the viscoelastic material in the eye from the
incision was able to be reduced.
[0142] The O-ring 43 described above is mounted on the pushing
shaft 116 of the insertion device 102 in FIG. 22. In this manner,
the O-ring 43 may be used in the conventional type insertion device
102 in FIG. 20.
[0143] Next, the function of the O-ring 43 will be described with
reference to FIGS. 23A and 23B. As shown in FIG. 23A, in an
assembly completion state of the insertion device 2 (before pushing
of the pushing shaft 16), the O-ring (the second elastic member) 43
that contacts the conical surface 12f formed in the inner periphery
of the rear end of the outer cylindrical portion 12a and the seal
cap 14 (the ring portion 14a: the first elastic member) secured to
the pushing shaft 16 are close to each other. However, even in this
state, the pushing shaft 16 is supported by two points: the ring
portion 14a of the seal cap 14 and the O-ring 43 with respect to
the main body 12, and thus as compared with the case where the
pushing shaft 16 is supported only by the ring portion 14a of the
seal cap 14, vertical and lateral displacement of the pushing shaft
16 relative to the main body 12 can be suppressed.
[0144] When the pushing shaft 16 is pushed in the front end
direction in this state as shown in FIG. 23B, the seal cap 14
secured to the pushing shaft 16 is moved with the pushing shaft 16
in the front end direction, while the O-ring 43 mounted axially
movably relative to the pushing shaft 16 is prevented from moving
in the front end direction by the conical surface 12f, and thus
remains in a position where the O-ring 43 contacts the conical
surface 12f. This increases a distance L between the ring portion
14a of the seal cap 14 and the O-ring 43. Thus, as compared with
the state before pushing of the pushing shaft 16, vertical and
lateral displacement of the pushing shaft 16 relative to the main
body 12 can be minimized. Thus, the front end (the lens grip
portion 16d) of the pushing shaft 16 can be precisely guided with
respect to the optical portion 1a of the lens 1 held by the lens
holding member 28, and the lens 1 can be properly pushed out.
[0145] The O-ring 43 may be mounted on the pushing shaft 16 or may
be secured to the inner periphery of the main body 12. A plurality
of members corresponding to the O-ring 43 may be provided rather
than one. Further, a plurality of O-rings 43 are placed axially
adjacent to each other, and brought into press contact with the
inner peripheral surface of the main body 12 and the outer
peripheral surface of the pushing shaft 16 to provide the sealing
function, thus leakage of the liquid from the rear end opening 12i
of the main body 12 can be more reliably prevented in combination
with the sealing function of the seal cap 14.
[0146] An elastic member corresponding to the O-ring 43 may be
secured on the front end side of the main body from the seal cap on
the pushing shaft so that the distance between the plurality of
elastic members corresponding to the O-ring and the seal cap is
reduced from a maximum state to a moderate state with the movement
of the pushing shaft in the front end direction. Also in this case,
as compared with the case where the elastic member corresponding to
the seal cap only is provided, vertical and lateral displacement of
the pushing shaft relative to the main body can be minimized, and
the lens can be properly pushed out.
[0147] As described above, according to the embodiment, the
peripheral wall from the lens housing portion to the insertion
cylindrical portion is formed without an opening or a gap, thereby
reliably preventing the liquid inside from leaking outside.
Further, the lens holding member can be inserted into the lens
housing portion from the rear, and thus the lens can be easily set
into the lens housing portion.
[0148] Further, the lens holding member placed in the lens housing
portion can reliably hold the lens in a predetermined shape, and
thus the lens is not moved or deformed by the flow of the liquid in
the main body, and the insertion device housing the lens can be
properly stored. In this case, the need for introducing the liquid
into the insertion device immediately before an operation is
eliminated, thereby reducing a burden on an operator or an
assistant.
[0149] The cover portion that covers at least part of the incision
in the eye is provided in the insertion cylinder, and thus the
amount of leakage, from the gap in the incision, of the liquid that
is supplied into the eye from the insertion cylinder can be
restricted. Thus, even if the amount of liquid supplied into the
eye is small, ocular tension can be increased to sufficiently
inflate the anterior chamber, thereby allowing the lens to be
smoothly inserted into the eyeball.
[0150] Further, the plurality of elastic members are placed between
the pushing shaft and the main body so that the distance
therebetween is changeable with movement of the pushing shaft
relative to the main body, and thus for example, the distance
between the plurality of elastic members is increased with movement
of the pushing shaft in a lens insertion direction. The plurality
of elastic members are provided to minimize radial displacement of
the pushing shaft relative to the main body. Thus, the front end of
the pushing shaft can be precisely guided with respect to the lens,
and the lens can be properly pushed out.
[0151] In the embodiment, a so-called preload type insertion device
has been described in which the lens 1 is previously set in the
lens housing portion 12b before factory shipment (before delivery
to a hospital). However, alternative embodiments of the present
invention may include other types of insertion devices. For
example, an insertion device in which it is stored separately from
a lens and the lens 1 is set immediately before an operation can be
used.
[0152] Furthermore, the present invention is not limited to these
preferred embodiments and various variations and modifications may
be made without departing from the scope of the present
invention.
[0153] This application claims foreign priority benefits based on
Japanese Patent Applications Nos. 2006-139560, filed on May 18,
2006, 2006-139561, filed on May 18, 2006 and 2006-155051, filed on
Jun. 2, 2006 and each of which is hereby incorporated by reference
herein in its entirety as if fully set forth herein.
* * * * *