U.S. patent application number 09/753568 was filed with the patent office on 2001-05-24 for corneal surgical apparatus.
This patent application is currently assigned to NIDEK CO., LTD.. Invention is credited to Shibata, Ryoji, Sugimura, Masahiro.
Application Number | 20010001829 09/753568 |
Document ID | / |
Family ID | 26396603 |
Filed Date | 2001-05-24 |
United States Patent
Application |
20010001829 |
Kind Code |
A1 |
Sugimura, Masahiro ; et
al. |
May 24, 2001 |
Corneal surgical apparatus
Abstract
A corneal surgical apparatus for incising a cornea of a
patient's eye in a layered form includes: a suction ring unit,
having a circular opening, that is to be vacuum-fixed onto a
peripheral part of the cornea; a rotatable shaft; an eccentric pin
projecting from a distal end of the shaft, the eccentric pin being
located at a position offset from a rotational central axis of the
shaft; and a cutting unit movable in an incising direction above
the suction ring unit. The cutting unit including: cornea
applanating means that applanates the cornea within the opening
into a substantially flat form; a blade that incises the cornea; a
first oscillation transmitting member having a part with which the
eccentric pin is engaged; a second oscillation transmitting member
having a part with which a part of the first oscillation
transmitting member is engaged; and a holder that holds the first
and second oscillation transmitting members to be movable in a
lateral direction which is perpendicular to the rotational central
axis of the shaft. Movement of the second oscillation transmitting
member in the lateral direction causes the blade to be moved in the
same direction.
Inventors: |
Sugimura, Masahiro; (Aichi,
JP) ; Shibata, Ryoji; (Aichi, JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT &
DUNNER LLP
1300 I STREET, NW
WASHINGTON
DC
20005
US
|
Assignee: |
NIDEK CO., LTD.
|
Family ID: |
26396603 |
Appl. No.: |
09/753568 |
Filed: |
January 4, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09753568 |
Jan 4, 2001 |
|
|
|
09517188 |
Mar 2, 2000 |
|
|
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Current U.S.
Class: |
606/166 |
Current CPC
Class: |
A61F 9/013 20130101 |
Class at
Publication: |
606/166 |
International
Class: |
A61F 009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 3, 1999 |
JP |
P. HEI. 11-55696 |
Mar 31, 1999 |
JP |
P. HEI. 11-90337 |
Claims
What is claimed is:
1. A corneal surgical apparatus for incising a cornea of a
patient's eye in a layered form, comprising: a suction ring unit,
having a circular opening, that is to be vacuum-fixed onto a
peripheral part of the cornea; a rotatable shaft; an eccentric pin
projecting from a distal end of the shaft, the eccentric pin being
located at a position offset from a rotational central axis of the
shaft; and a cutting unit movable in an incising direction above
the suction ring unit, the cutting unit including: cornea
applanating means that applanates the cornea within the opening
into a substantially flat form; a blade that incises the cornea; a
first oscillation transmitting member having a part with which the
eccentric pin is engaged; a second oscillation transmitting member
having a part with which a part of the first oscillation
transmitting member is engaged; and a holder that holds the first
and second oscillation transmitting members to be movable in a
lateral direction which is perpendicular to the rotational central
axis of the shaft, wherein movement of the second oscillation
transmitting member in the lateral direction causes the blade to be
moved in the same direction.
2. A corneal surgical apparatus according to claim 1, wherein the
blade is fixed to the second oscillation transmitting member.
3. A corneal surgical apparatus according to claim 1, wherein the
first oscillation transmitting member includes: a vertical groove
elongating in a direction perpendicular to both of the lateral
direction and the rotational central axis of the shaft, the
eccentric pin being engaged with the vertical groove; and a pin
part extending toward the second oscillation transmitting member;
wherein the second oscillation transmitting member includes a pin
receiving part with which the pin part of the first oscillation
transmitting member is engaged.
4. A corneal surgical apparatus according to claim 1, wherein the
holder holds the first and second oscillation transmitting member
to be movable linearly in the lateral direction.
5. A corneal surgical apparatus according to claim 1, wherein the
first oscillation transmitting member includes a shaft part
rotatable about an axis different in location from the rotational
central axis of the shaft, the shaft part having at least one of a
recess and a protrusion, and wherein the holder includes a bearing
part that rotatably supports the shaft part and that has a part
with which the shaft part is engaged, the holder holding the first
oscillation transmitting member to be rockable in the lateral
direction.
6. A corneal surgical apparatus according to claim 5, wherein the
holder holds the second oscillation transmitting member to be
movable linearly in the lateral direction.
7. A corneal surgical apparatus according to claim 5, wherein the
shaft part of the first oscillation transmitting member includes
two shaft parts respectively located on an upper part and a lower
part of the first oscillation transmitting member, and wherein the
bearing part includes two bearing parts respectively supporting the
two shaft parts.
8. A corneal surgical apparatus according to claim 5, wherein the
shaft part of the first oscillation transmitting member is
rotatable about an axis intersecting the rotational central axis of
the shaft.
9. A corneal surgical apparatus according to claim 8, wherein the
rotational central axis of the shaft part of the first oscillation
transmitting member intersects the rotational central axis of the
shaft perpendicularly.
10. A corneal surgical apparatus according to claim 9, wherein the
eccentric pin is provided on an axis passing through an
intersecting point at which the rotational central axis of the
shaft part intersects the rotational central axis of the shaft.
11. A corneal surgical apparatus according to claim 1, wherein the
eccentric pin is provided on an axis non-perpendicularly
intersecting the rotational central axis of the shaft.
12. A corneal surgical apparatus according to claim 1, further
comprising: a drive unit that rotates the shaft.
13. A corneal surgical apparatus according to claim 1, further
comprising: a drive unit that moves the cutting unit in the
incising direction.
14. A corneal surgical apparatus for incising a cornea of a
patient's eye in a layered form, comprising: a suction ring unit,
having a circular opening, that is to be vacuum-fixed onto a
peripheral part of the cornea; a rotatable shaft; an eccentric pin
projecting from a distal end of the shaft, the eccentric pin being
located at a position offset from a rotational central axis of the
shaft; and a cutting unit movable in an incising direction above
the suction ring unit, the cutting unit including: cornea
applanating means that applanates the cornea within the opening
into a substantially flat form; a blade that incises the cornea; a
rock transmitting member having a part with which the eccentric pin
is engaged and a shaft part rotatable about an axis different in
location from the rotational central axis of the shaft, the shaft
part having at least one of a recess and a protrusion; and a holder
that holds the rock transmitting members to be rockable in a
lateral direction which is perpendicular to the rotational central
axis of the shaft, the holder having a bearing part rotatably
supporting the shaft part of the rock transmitting member, the
bearing part having a part with which the shaft part is engaged,
wherein movement of the rock transmitting member in the lateral
direction causes the blade to be moved in the same direction.
15. A corneal surgical apparatus according to claim 14, wherein the
shaft part of the rock transmitting member includes two shaft parts
respectively located on an upper part and a lower part of the rock
transmitting member, and wherein the bearing part includes two
bearing parts respectively supporting the two shaft parts.
16. A corneal surgical apparatus according to claim 14, wherein the
shaft part of the rock transmitting member is rotatable about an
axis intersecting the rotational central axis of the shaft.
17. A corneal surgical apparatus according to claim 16, wherein the
rotational central axis of the shaft part of the rock transmitting
member perpendicularly intersects the rotational central axis of
the shaft.
18. A corneal surgical apparatus according to claim 17, wherein the
eccentric pin is provided on an axis passing through an
intersecting point at which the rotational central axis of the
shaft part intersects the rotational central axis of the shaft.
19. A corneal surgical apparatus according to claim 14, wherein the
eccentric pin is provided on an axis which non-perpendicularly
intersects the rotational central axis of the shaft.
20. A corneal surgical apparatus according to claim 14, further
comprising: a drive unit that rotates the shaft.
21. A corneal surgical apparatus according to claim 14, further
comprising: a drive unit that moves the cutting unit in the
incising direction.
22. A corneal surgical apparatus for incising a cornea of a
patient's eye in a layered form, comprising: a suction ring unit,
having a circular opening, that is to be vacuum-fixed onto a
peripheral part of the cornea; a rotatable shaft; an eccentric pin
projecting from a distal end of the shaft, the eccentric pin being
provided on an axis non-parallel to and non-perpendicular to a
rotational central axis of the shaft; and a cutting unit movable in
an incising direction above the suction ring unit, the cutting unit
including: cornea applanating means that applanates the cornea
within the opening into a substantially flat form; a blade that
incises the cornea; a transmitting member having a part with which
the eccentric pin is engaged; and a holder that holds the
transmitting member to be movable in a lateral direction which is
perpendicular to the rotational central axis of the shaft, wherein
movement of the transmitting member in the lateral direction causes
the blade to be moved in the same direction.
23. A corneal surgical apparatus according to claim 22, wherein the
eccentric pin is provided on an axis that non-perpendicularly
intersects the rotational central axis of the shaft.
24. A corneal surgical apparatus according to claim 22, further
comprising: a drive unit that rotates the shaft.
25. A corneal surgical apparatus according to claim 22, further
comprising: a drive unit that moves the cutting unit in the
incising direction.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a corneal surgical
apparatus for incising the cornea of an eye of a patient in a
layered form at the time of a keratorefrative surgery or the
like.
[0003] 2. Description of the Related Art
[0004] In recent years, attention has been focused on a LASIK
surgery (laser in situ keratomileusis) for the keratorefractive
surgery wherein a flap is formed by incising a portion with a
thickness of about 0.15 mm from the corneal epithelium to the
corneal stroma with a part of the cornea remaining connected like a
hinge, ablating the corneal stroma in a refractive correction
amount by an excimer laser light, and returning the flap to its
original position. In the LASIK surgery, a corneal surgical
apparatus called microkeratome is used for incising the cornea in a
layered form.
[0005] As a corneal surgical apparatus, one comprising a suction
ring to be vacuum-fixed to a part of the cornea from a corneal ring
portion to the surface of the conjunctiva, a cornea applanating
member for applanating the cornea flatly, and a blade movable
toward the hinge while being oscillated laterally so as to incise
the flattened cornea into a layer form with a substantially uniform
thickness, is known.
[0006] As a mechanism for the blade lateral oscillation, as shown
in FIG. 13A, one comprising a rotation shaft 301 to be rotated by a
driving device such as a motor, an eccentric pin 302 provided at
the tip end of the shaft 301, a transmitting member 304 having a
vertical groove 303 to be engaged with the pin 302 is proposed. The
transmitting member 304 having a blade 300 fixed thereto is held
movably in the lateral direction (right and left direction, that
is, the direction perpendicular to the paper surface in FIG. 13) in
a receiving groove formed in a blade holder 305 and a holder block
306. When the shaft 301 is rotated by drive of the motor, force is
applied on the transmitting member 304 in the lateral direction
according to the circumferential movement (circular motion) of the
pin 302 engaged with the vertical groove 303. Accordingly, the
transmitting member 304 oscillated laterally (moved in the right
and left direction), and further, the blade 300 fixed to the
transmitting member 304 is oscillated laterally as well.
[0007] However, according to the conventional mechanism, as shown
in FIG. 13B, by the circumferential movement of the pin 302, not
only the force in the lateral direction but also force in the
vertical direction (up and down direction) is applied to the
transmitting member 304. That is, since the pin 302 with the
circumferential movement comes in contact with the wall of the
vertical groove 303 so that force is applied on the transmitting
member 304 in the vertical direction due to the friction force
generated by the contact, the transmitting member 304 is oscillated
laterally while being moved also in the vertical direction.
Therefore, if the shaft 301 is rotated at a high speed, the
transmitting member 304 and the blade 300 generate vertical
oscillation (up and down movement) called "rampage" in addition to
the lateral oscillation.
[0008] The "rampage" hinders stable incision as well as generates a
loss in terms of the efficiency of converting the rotational motion
to the lateral oscillation. Moreover, since the corner part of the
transmitting member 304 is contacted with a blade holder 305 and
the holder block 306 frequently so as to be applied with a large
force, the parts are worn out rapidly so that the life cycle
thereof is shortened.
[0009] The displacement amount of the transmitting member 304 to be
displaced vertically and laterally (in the up and down, and right
and left directions) according to the circumferential movement of
the pin 302 corresponds to the eccentric amount of the pin 302, but
as to the vertical direction, since the transmitting member 304 is
held by the blade holder 305 and the holder block 306 in the
vertical direction, the transmitting member 304 (and the blade 300)
is displaced (vertical oscillation) for the gap with respect to
each member. Therefore, accurate production without a gap among the
transmitting member 304, the blade holder 305 and the holder block
306 would prevent the vertical oscillation (that is, "rampage"),
however, much labor is required for meeting the demand particularly
in mass production so as to increase the cost.
SUMMARY OF THE INVENTION
[0010] In view of the above-mentioned problems, an object of the
present invention is to provide a corneal surgical apparatus
capable of forming a good flap by preventing "rampage" of a blade.
Effects of the apparatus include efficient generation of lateral
oscillation, restraint of the cost rise according to high accuracy
of the mechanism, and high durability.
[0011] In order to solve the above-mentioned problems, the
invention is characterized by the following features.
[0012] (1) A corneal surgical apparatus for incising a cornea of a
patient's eye in a layered form, comprising:
[0013] a suction ring unit, having a circular opening, that is to
be vacuum-fixed onto a peripheral part of the cornea;
[0014] a rotatable shaft;
[0015] an eccentric pin projecting from a distal end of the shaft,
the eccentric pin being located at a position offset from a
rotational central axis of the shaft; and
[0016] a cutting unit movable in an incising direction above the
suction ring unit, the cutting unit including:
[0017] cornea applanating means that applanates the cornea within
the opening into a substantially flat form;
[0018] a blade that incises the cornea;
[0019] a first oscillation transmitting member having a part with
which the eccentric pin is engaged;
[0020] a second oscillation transmitting member having a part with
which a part of the first oscillation transmitting member is
engaged; and
[0021] a holder that holds the first and second oscillation
transmitting members to be movable in a lateral direction which is
perpendicular to the rotational central axis of the shaft,
[0022] wherein movement of the second oscillation transmitting
member in the lateral direction causes the blade to be moved in the
same direction.
[0023] (2) A corneal surgical apparatus according to (1), wherein
the blade is fixed to the second oscillation transmitting
member.
[0024] (3) A corneal surgical apparatus according to (1), wherein
the first oscillation transmitting member includes:
[0025] a vertical groove elongating in a direction perpendicular to
both of the lateral direction and the rotational central axis of
the shaft, the eccentric pin being engaged with the vertical
groove; and
[0026] a pin part extending toward the second oscillation
transmitting member;
[0027] wherein the second oscillation transmitting member includes
a pin receiving part with which the pin part of the first
oscillation transmitting member is engaged.
[0028] (4) A corneal surgical apparatus according to (1), wherein
the holder holds the first and second oscillation transmitting
member to be movable linearly in the lateral direction.
[0029] (5) A corneal surgical apparatus according to (1), wherein
the first oscillation transmitting member includes a shaft part
rotatable about an axis different in location from the rotational
central axis of the shaft, the shaft part having at least one of a
recess and a protrusion, and
[0030] wherein the holder includes a bearing part that rotatably
supports the shaft part and that has a part with which the shaft
part is engaged, the holder holding the first oscillation
transmitting member to be rockable in the lateral direction.
[0031] (6) A corneal surgical apparatus according to (5), wherein
the holder holds the second oscillation transmitting member to be
movable linearly in the lateral direction.
[0032] (7) A corneal surgical apparatus according to (5), wherein
the shaft part of the first oscillation transmitting member
includes two shaft parts respectively located on an upper part and
a lower part of the first oscillation transmitting member, and
[0033] wherein the bearing part includes two bearing parts
respectively supporting the two shaft parts.
[0034] (8) A corneal surgical apparatus according to (5), wherein
the shaft part of the first oscillation transmitting member is
rotatable about an axis intersecting the rotational central axis of
the shaft.
[0035] (9) A corneal surgical apparatus according to (8), wherein
the rotational central axis of the shaft part of the first
oscillation transmitting member intersects the rotational central
axis of the shaft perpendicularly.
[0036] (10) A corneal surgical apparatus according to (9), wherein
the eccentric pin is provided on an axis passing through an
intersecting point at which the rotational central axis of the
shaft part intersects the rotational central axis of the shaft.
[0037] (11) A corneal surgical apparatus according to (1), wherein
the eccentric pin is provided on an axis non-perpendicularly
intersecting the rotational central axis of the shaft.
[0038] (12) A corneal surgical apparatus according to (1), further
comprising:
[0039] a drive unit that rotates the shaft.
[0040] (13) A corneal surgical apparatus according to (1), further
comprising:
[0041] a drive unit that moves the cutting unit in the incising
direction.
[0042] (14) A corneal surgical apparatus for incising a cornea of a
patient's eye in a layered form, comprising:
[0043] a suction ring unit, having a circular opening, that is to
be vacuum-fixed onto a peripheral part of the cornea;
[0044] a rotatable shaft;
[0045] an eccentric pin projecting from a distal end of the shaft,
the eccentric pin being located at a position offset from a
rotational central axis of the shaft; and
[0046] a cutting unit movable in an incising direction above the
suction ring unit, the cutting unit including:
[0047] cornea applanating means that applanates the cornea within
the opening into a substantially flat form;
[0048] a blade that incises the cornea;
[0049] a rock transmitting member having a part with which the
eccentric pin is engaged and a shaft part rotatable about an axis
different in location from the rotational central axis of the
shaft, the shaft part having at least one of a recess and a
protrusion; and
[0050] a holder that holds the rock transmitting members to be
rockable in a lateral direction which is perpendicular to the
rotational central axis of the shaft, the holder having a bearing
part rotatably supporting the shaft part of the rock transmitting
member, the bearing part having a part with which the shaft part is
engaged,
[0051] wherein movement of the rock transmitting member in the
lateral direction causes the blade to be moved in the same
direction.
[0052] (15) A corneal surgical apparatus according to (14), wherein
the shaft part of the rock transmitting member includes two shaft
parts respectively located on an upper part and a lower part of the
rock transmitting member, and
[0053] wherein the bearing part includes two bearing parts
respectively supporting the two shaft parts.
[0054] (16) A corneal surgical apparatus according to (14), wherein
the shaft part of the rock transmitting member is rotatable about
an axis intersecting the rotational central axis of the shaft.
[0055] (17) A corneal surgical apparatus according to (16), wherein
the rotational central axis of the shaft part of the rock
transmitting member perpendicularly intersects the rotational
central axis of the shaft.
[0056] (18) A corneal surgical apparatus according to (17), wherein
the eccentric pin is provided on an axis passing through an
intersecting point at which the rotational central axis of the
shaft part intersects the rotational central axis of the shaft.
[0057] (19) A corneal surgical apparatus according to (14), wherein
the eccentric pin is provided on an axis which non-perpendicularly
intersects the rotational central axis of the shaft.
[0058] (20) A corneal surgical apparatus according to (14), further
comprising:
[0059] a drive unit that rotates the shaft.
[0060] (21) A corneal surgical apparatus according to (14), further
comprising:
[0061] a drive unit that moves the cutting unit in the incising
direction.
[0062] (22) A corneal surgical apparatus for incising a cornea of a
patient's eye in a layered form, comprising:
[0063] a suction ring unit, having a circular opening, that is to
be vacuum-fixed onto a peripheral part of the cornea;
[0064] a rotatable shaft;
[0065] an eccentric pin projecting from a distal end of the shaft,
the eccentric pin being provided on an axis non-parallel to and
non-perpendicular to a rotational central axis of the shaft;
and
[0066] a cutting unit movable in an incising direction above the
suction ring unit, the cutting unit including:
[0067] cornea applanating means that applanates the cornea within
the opening into a substantially flat form;
[0068] a blade that incises the cornea;
[0069] a transmitting member having a part with which the eccentric
pin is engaged; and
[0070] a holder that holds the transmitting member to be movable in
a lateral direction which is perpendicular to the rotational
central axis of the shaft,
[0071] wherein movement of the transmitting member in the lateral
direction causes the blade to be moved in the same direction.
[0072] (23) A corneal surgical apparatus according to (22), wherein
the eccentric pin is provided on an axis that non-perpendicularly
intersects the rotational central axis of the shaft.
[0073] (24) A corneal surgical apparatus according to (22), further
comprising:
[0074] a drive unit that rotates the shaft.
[0075] (25) A corneal surgical apparatus according to (22), further
comprising:
[0076] a drive unit that moves the cutting unit in the incising
direction.
[0077] The present disclosure relates to the subject matter
contained in Japanese patent application Nos. Hei. 11-55696 (filed
on Mar. 3, 1999) and Hei. 11-90337 (filed on Mar. 31, 1999), which
are expressly incorporated herein by reference in their
entireties.
BRIEF DESCRIPTION OF THE DRAWINGS
[0078] FIG. 1 is a cross-sectional view of an apparatus according
to a first embodiment and a schematic diagram of a control
system.
[0079] FIG. 2 is an enlarged explanatory diagram of a cutting unit
and a suction unit of the apparatus according to the first
embodiment.
[0080] FIG. 3 is a cross-sectional view taken on the line A-A of
FIG. 2, illustrating the cutting unit of the apparatus according to
the first embodiment.
[0081] FIG. 4 is a cross-sectional view taken on the line B-B of
FIG. 2, illustrating the cutting unit of the apparatus according to
the first embodiment.
[0082] FIGS. 5A and 5B are explanatory diagrams for the movement of
two oscillation transmitting members and a blade in the apparatus
according to the first embodiment.
[0083] FIG. 6 is an explanatory diagram for the difference of the
blade positions in the conventional apparatus and the apparatus
according to the first embodiment.
[0084] FIG. 7 is a diagram of a modified embodiment of the cutting
unit of the apparatus according to the first embodiment.
[0085] FIG. 8 is a cross-sectional view of an apparatus according
to a second embodiment and a schematic diagram of a control
system.
[0086] FIG. 9 is an enlarged explanatory diagram of a cutting unit
and a suction unit of the apparatus according to the second
embodiment.
[0087] FIG. 10 is a cross-sectional view taken on the line C-C of
FIG. 9, illustrating the cutting unit of the apparatus according to
the second embodiment.
[0088] FIG. 11 is an explanatory diagram for conversion of the
motion in the apparatus according to the second embodiment.
[0089] FIG. 12 is a diagram of a modified embodiment of the cutting
unit of the apparatus according to the second embodiment.
[0090] FIGS. 13A and 13B are explanatory diagrams for the
configuration of a cutting unit, and the movement of a transmitting
member and a blade in a conventional mechanism.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
[0091] Hereinafter an embodiment of the invention will be explained
with reference to the drawings. FIG. 1 is a cross-sectional view of
a corneal surgical apparatus according to a first embodiment and a
schematic diagram of a control system.
[0092] Reference numeral 1 denotes a main body of the apparatus,
and numeral 1a denotes a grip portion to be held by an operator
during a surgery. A suction unit 3 for fixation to the patient's
eye, and a cutting unit 2 having a blade 20 for incising the
cornea, to be moved rectilinearly above the suction unit 3 are
provided on the front side (left side in the figure) of the main
body 1.
[0093] A feed motor 11 for rectilinearly moving the cutting unit 2
in the incising direction is fixed in the main body 1, with a feed
screw 13 having a threaded portion corresponding in length to the
rectilinear movement of the cutting unit 2, attached to the
rotation shaft of the motor 11. An oscillating motor 12 for
imparting lateral oscillation to the blade, and a connecting member
17 to be connected with the cutting unit 2 at its tip portion are
fixed to an attaching member 14 to be screwed into the threaded
portion of the screw 13. A rotation shaft 15 mounted on the
rotation shaft of the motor 12 is held by the connecting member 17
rotatably. An eccentric pin 16 is embedded on the tip of the shaft
15 at a position offset from the rotation center (rotation central
axis), projecting therefrom. The cutting unit 2 moves forward or
backward with the motor 12 and the connecting member 17 mounted on
the attaching member 14 according to the forward or reverse
rotation of the motor 11.
[0094] Next, the configuration of the cutting unit 2 and the
suction unit 3 will be explained with reference to FIGS. 2, 3 and
4. FIG. 2 is an enlarged explanatory diagram of the cutting unit 2
and the suction unit 3 of the apparatus according to the first
embodiment. FIG. 3 is a cross-sectional view taken on the line A-A
of FIG. 2, and FIG. 4 is a cross-sectional view taken on the line
B-B of FIG. 2.
[0095] The cutting unit 2 comprises the blade 20, a blade holder
21a, a holder block 21b, a first oscillation transmitting member
22, and a second oscillation transmitting member 23. A rotation
hole in which the shaft 15 is inserted is provided in the holder
block 21b so that the tip portion of the connecting member 17 is
fixed thereto.
[0096] A metal blade having a blade edge of stainless steel, or
steel, or an ore blade having a blade edge of diamond or sapphire
is used as the blade 20. The blade 20 is held between the blade
holder 21a and the holder block 21b laterally oscillatably with an
appropriate angle with respect to the horizontal plane. A shallow
recess 210a is formed at a portion, where the blade 20 is to be
placed, at the blade holder 21a side. The lateral width of the
recess 210a is provided larger than the oscillation width of the
lateral oscillation of the blade 20.
[0097] The first transmitting member 22 is held laterally movably
in an oscillating space 210c formed in the holder block 21b.
Further, a vertical groove 22a to be engaged with the pin 16 is
formed in the first transmitting member 22. When the shaft 15 is
rotated by the rotation drive of the motor 12, a lateral force is
applied to the first transmitting member 22 according to the
circumferential movement of the pin 16 engaged with the vertical
groove 22a. Accordingly, the first transmitting member 22
oscillates laterally.
[0098] The second transmitting member 23 is held laterally movably
in an oscillating space 210b formed in the holder block 21b.
Further, a vertical groove 23a to be engaged with a pin part 22b
provided below the first transmitting member 22 is formed in the
second transmitting member 23. When the first transmitting member
22 is oscillated laterally by the rotation of the shaft 15
(circumferential movement of the pin 16), the lateral oscillation
provides a lateral force to the second transmitting member 23 via
the pin part 22b and the vertical groove 23a. Accordingly, the
second transmitting member 23 oscillates laterally, and further,
the blade 20 fixed to the second transmitting member 23 oscillates
laterally as well.
[0099] The movement of the first transmitting member 22, the second
transmitting member 23, and the blade 20 will be explained with
reference to FIGS. 5A and 5B.
[0100] The first transmitting member 22 moves reciprocally in the
lateral direction (X direction) (this will be referred to as a
first lateral oscillation) as well as moves reciprocally in the
vertical direction (Y direction) (this will be referred to as a
first vertical oscillation) according to the circumferential
movement of the pin 16 according to the rotation of the shaft 15
(according to split of the force generated by the circumferential
movement of the pin 16 into the pushing force for pushing the side
surface of the vertical groove 22a and the friction force
functioning in the vertical direction on the side surface of the
vertical groove 22a) as shown in FIG. 5A. The dashed line D1 in the
figure denotes the locus of the movement of the point P, which is
the center of the pin part 22b.
[0101] The second transmitting member 23 moves reciprocally in the
lateral direction (X direction) (this will be referred to as a
second lateral oscillation) as well as slightly moves reciprocally
in the vertical direction (Y direction) (this will be referred to
as a second vertical oscillation) according to the movement of the
pin part 22b of the first transmitting member 22 as shown in FIG.
5B. The dashed line D2 in the figure denotes the locus of the
movement of the point Q, which is the center of the blade 20.
[0102] The displacement amount in the lateral direction according
to the first vertical oscillation is based on the distance of the
gap between the first transmitting member 22 and the holder block
21b. In contrast, the displacement amount in the vertical direction
according to the second vertical oscillation is much smaller than
that of the first vertical oscillation because the circumferential
movement of the pin 16 is converted to the first lateral
oscillation already, thereby generating the second lateral
oscillation (the displacement amount in the lateral direction of
the first lateral oscillation and the second lateral oscillation is
same, and it corresponds to the eccentric amount of the pin 16).
Moreover, the displacement amount difference in the vertical
direction according to the second vertical oscillation derived from
the gap at the time of generating the first lateral oscillation and
the gap at the time of generating the second vertical oscillation
is small because the displacement amount itself is extremely
small.
[0103] As mentioned above, the locus D2 has a smaller displacement
amount in the vertical direction compared with the locus D1. That
is, the second transmitting member 23 has a smaller displacement
amount in the vertical oscillation at the time of the lateral
oscillation with respect to the first transmitting member 22.
Accordingly, the "rampage" can be restrained at the time of the
lateral oscillation.
[0104] Furthermore, as shown in FIG. 6, according to the
conventional apparatus configuration, the position of a blade 400
in the up and down direction is limited due to the radius
(diameter) of a rotation shaft 401, the circumferential movement of
an eccentric pin 402, and the displacement amount in the vertical
direction (vertical groove 403). In contrast, according to an
apparatus of the invention, since the position of the blade 20 in
the up and down direction is limited onto to the displacement
amount in the vertical direction (vertical groove 23a), and
further, the displacement amount in the vertical direction is
smaller than the conventional configuration, the point of action
for transmitting the lateral oscillation to the second transmitting
member 23 can be provided adjacent to the blade 20, to which the
load is applied. Therefore, the second transmitting member 23 can
be made smaller than the conventional transmitting member 404 (see
FIG. 7). Accordingly, the rotation torque applied on the blade 20
is smaller than the conventional configuration, and thus the blade
20 can efficiently be oscillated laterally so that the "rampage"
can be smaller.
[0105] In FIG. 2, a cornea applanating part 24 is fixed to the
holder block 21b by an attaching member 24a so as to be provided on
the front side (left side in the figure) of the blade 20. The
cornea applanating part 24 moves according to the movement of the
cutting unit 2 for applanating the cornea of the patient's eye
flatly preceding incision with the blade 20. Since the blade 20
incises the cornea thus applanated flatly by the applanating part
24, a flap of a uniform layer is formed. The distance between the
edge of the blade 20 attached to the blade holder 21a and the lower
surface of the applanating part 24 is about 150 .mu.m so that the
cornea can be incised with this thickness in a layered form.
[0106] The suction unit 3 comprises a fixing member 30, a suction
ring 31, and a suction pipe 32. The suction ring 31 is fixed to the
main body 1 by the fixing member 30. The suction ring 31 having a
substantially cylindrical shape with a U-shaped cross-section,
comprises a circular recess 31a to be contacted with the patient's
eye and an opening 31b concentric with the recess 31a. When the
suction ring 31 is set on the patient's eye for surgery, the cornea
of the patient's eye projects upward from the opening 31b so that
the lower end portion of the suction ring 31 and the opening end
portion of the opening 31b are contacted so as to provide a space S
for suction.
[0107] The suction pipe 32 is embedded in the suction ring 31, and
connected with a vacuum tube (not illustrated) elongating to a pump
41. A suction path 32a provided inside the suction pipe 32
communicates with the recess 31a. According to suction and
discharge of the air in the space S by the pump 41 via the suction
path 32a, the suction ring 31 is vacuum-fixed to the patient's eye.
In this fixation, as the operator holds the grip portion 1a,
positioning of the opening 31b can be facilitated, and the
apparatus can be held stably.
[0108] In addition, a pipe for pressure detection (not illustrated)
is embedded in the suction ring 31 at a position facing to the
suction pipe 32. The pipe for pressure detection is connected with
a pressure detector 33 via a tube (not illustrated). The pressure
detector 33 detects the air pressure in the space S sucked by the
pump 41 via the pipe for pressure detection. A control unit 40
controls the operation of the motor 11, the motor 12, and the pump
41 based on the air pressure detected by the pressure detector
33.
[0109] Hereinafter the operation of the apparatus with the
above-mentioned configuration will be described. While confirming
the state of inclination of the suction ring 31 (main body 1) and
the position of the pupillary center based on a mark applied on the
cornea of the patient's eye with an instrument such as a marker,
the operator positions the center of the opening 31b with respect
to the pupillary center and disposes the suction ring 31 on the
patient's eye.
[0110] After installation of the suction ring 31, the operator
operates the pump 41 so as to suck the air in the space S between
the suction ring 31 and the patient's eye while keeping the
position and the posture of the main body 1 for thereby reducing
the air pressure (to the negative pressure). When the air pressure
in the space S is reduced to a certain value (when it reaches a
sufficiently negative pressure), the operation of the pump 41 is
controlled by the control unit 40 so as to maintain the air
pressure. Accordingly, the suction ring 31 is vacuum-fixed onto the
patient's eye.
[0111] After completion of the fixation of the apparatus, the
operator operates a foot switch 42 for rotation drive of the motor
11 and the motor 12. The control unit 40 controls for rotation
drive of the motor 11 and the motor 12. The control unit 40
controls the drive of the motor 12 by the input of a drive command
signal by the foot switch 42 so as to oscillate the blade 20
laterally by a fixed or variable oscillation frequency. Further,
the control unit 40 controls the rotation of the motor 11 according
to a fixed or variable feeding speed so as to rectilinearly move
the cutting section 2 in the hinge direction. At the time, the
shaft 15 slides in the advancing direction integrally with the
cutting unit 2 while making a rotational motion for imparting
lateral oscillation to the blade 20.
[0112] After being converted to the lateral oscillation of the
first transmitting member 22, the rotational motion of the shaft 15
is converted to the lateral oscillation of the second transmitting
member so as to provide the rectilinear oscillation to the blade
20, and thus the "rampage" caused by the vertical oscillation can
be restrained so as to form a good flap stably.
[0113] When the edge of the blade 20 has incised the cornea with
the hinge portion left so as to complete the flap formation, the
motor 11 is rotated reversely so as to return the cutting unit 2 to
its initial position. At the time, the rotation of the motor 12 is
stopped according to the independent control of the motors so that
the blade 20 can be taken out from the flap while avoiding the
unnecessary oscillation of the blade 20. Accordingly, the
possibility of cut off of the thus formed flap can be reduced.
[0114] After the return of the cutting unit 2 to the initial
position, air is introduced into the space S so as to release the
suction for removing the apparatus (suction ring 31). Subsequently,
the corneal stroma is ablated for the refractive correction amount,
and then the flap is returned to its original position so as to
finish the surgery.
[0115] Although the first transmitting member 22 comprising the
vertical groove 22a to be engaged with the pin 16 and the pin part
22b, and the second transmitting member 23 comprising the vertical
groove 23a to be engaged with the pin part 22b of the first
transmitting member 22 (in this case, the blade 20 is fixed to the
second transmitting member 23) are used in this embodiment for
converting the rotation of the shaft 15 (circumferential movement
of the pin 16) to the lateral oscillation of the blade 20, it is
also possible to further provide a pin part similar to the pin part
22b in the second transmitting member and a third oscillation
transmitting member comprising a vertical groove to be engaged with
the pin part of the second transmitting member. In this case, the
blade is fixed to the third transmitting member. That is, although
the rotation of the rotation shaft is converted to the lateral
oscillation of the blade by the conversion by twice, but the
conversion needs to be at least twice and can be increased to three
times or four times.
Second Embodiment
[0116] Another embodiment of the invention will be explained with
reference to the drawings. FIG. 8 is a cross-sectional view of an
apparatus according to the second embodiment and a schematic
diagram of a control system. FIG. 9 is an enlarged cross-sectional
view of a cutting unit 2 and a suction unit 3. FIG. 10 is a
cross-sectional view taken on the line C-C of FIG. 9. The same
numerals are applied to the same components as in the first
embodiment.
[0117] The cutting unit 2 comprises the blade 20, the blade holder
21a, the holder block 21b, a bearing part 21c, a rock (swing)
transmitting member 25, and a lateral oscillation transmitting
member 26. A rotation hole in which the shaft 15 is inserted is
provided in the blade holder 21a so that the tip portion of the
connected member 17 is fixed thereto.
[0118] The rock transmitting member 25 is pivoted by the holder
block 21b and the bearing part 21c rotatably (rockably) with two
upper and lower rotation shaft parts 25c as the rotation central
axes in the oscillation space 210c formed in the holder block 21b
(that is, the rock transmitting member 25 is pivoted rockably in
the lateral direction, centering the axial line L elongating in the
vertical direction). Further, a vertical groove 25a to be engaged
with the pin 16 is formed in the rock transmitting member 25. When
the shaft 15 is rotated according to the rotation drive of the
motor 12, a force in the lateral direction is applied on the rock
transmitting member 25 by the circumferential movement of the pin
16 engaged with the vertical groove 25a. Accordingly the rock
transmitting member 25 is rocked.
[0119] The lateral oscillation transmitting member 26 is held
movably in the lateral direction in the oscillation space 210b
formed in the holder block 21b. A pin receiving part 26a to be
engaged with the a pin part 25b provided at a lower portion of the
rock transmitting member 25 is formed in the lateral oscillation
transmitting member 26. When the rock transmitting member 25 is
rocked in the lateral direction with the shaft parts 25c as the
rotation center by the rotation of the shaft 15 (circumferential
movement of the pin 16), a force in the lateral direction is
applied on the lateral oscillation transmitting member 26 via the
pin part 25b and the pin receiving part 26a according to the rock.
Accordingly, the lateral oscillation transmitting member 26
oscillates laterally, and further, the blade 20 fixed to the
oscillation transmitting member 26 oscillates laterally as
well.
[0120] The movement of the pin 16, the rock transmitting member 25,
the lateral oscillation transmitting member 26, and the blade 20
will be explained with reference to FIG. 11.
[0121] When the shaft 15 is rotated by the motor 12, the projecting
portion of the pin 16 provided eccentrically in the shaft 15 moves
circumferentially, centering the rotation central axis of the shaft
15. The force generated by the circumferential movement of the pin
16 can be split in the vertical and lateral directions, that is,
the force in the vertical direction functioning on the side surface
of the vertical groove 25a in the up and down direction as the
friction force, and the force in the lateral direction pushing the
side surface of the vertical groove 25a in the lateral direction as
the pushing force. According to the force applied on the side
surface of the vertical groove 25a, the rock transmitting member 25
rocks with the shaft parts 25c as the rotation center. Since the
shaft parts 25c are held sufficiently by the holder block 21b and
the bearing part 21c with respect to the force in the vertical
direction generated by the pin 16, the "rampage" in the vertical
direction an be restrained so that the rotational motion of the
shaft 15 can be converted efficiently to the rock of the rock
transmitting member 25.
[0122] According to the rock of the rock transmitting member 25 in
the lateral direction, the pin part 25b formed in the lower portion
thereof is rocked in the lateral direction with substantially no
displacement in the vertical direction. Since the pin part 25b
rocking in the lateral direction applies a force on the side
surface of the pin receiving part 26a, the lateral oscillation
transmitting member 26 oscillates in the lateral direction with the
oscillation space 210b as the guide. At the time, by providing a
substantially spherical tip end shape to the pin part 25b, a force
can be applied efficiently to the pin receiving part 26a so that
the lateral oscillation can be provided smoothly. Since the blade
20 is fixed to the lateral oscillation transmitting member 26, it
oscillates according to the lateral oscillation of the lateral
oscillation transmitting member 26.
[0123] According to the configuration, after being converted to the
rock with the shaft parts 25c of the rock transmitting member 25 as
the rotation center, the rotational motion of the shaft 15 applies
rectilinear oscillation to the blade 20 in the lateral direction.
Since the force according to the circumferential movement of the
pin 16 in the vertical direction is supported by the shaft parts
25c, the "rampage" by the vertical oscillation can be restrained so
that a good flap can be formed stably. Moreover, since the sliding
portion is only in the peripheral part of the shaft parts 25c, worn
out of the oscillating portion can be restrained so as to prolong
the life cycle of the parts.
[0124] The pin 16 can be attached to the shaft 15, elongating
parallel in the rotation central axis direction of the shaft 15 (as
in the conventional apparatus shown in FIG. 13A), but the pin 16 is
provided tilting with respect to the rotation central axis
direction of the shaft 15 in this embodiment. That is, the pin 16
is provided eccentrically, elongating passing through the
intersection of the axial line L passing through the rotation
center of the rock of the rock transmitting member 25 and the
rotation central axis of the shaft 15. According to the
configuration, since the rocking angle of the pin 16 in the lateral
direction and the rocking angle of the rock transmitting member 25
in the lateral direction coincide, the contacting property of the
pin 16 engaged with the vertical groove 25a is improved and thus
the rotational motion can be converted smoothly and efficiently to
the lateral rock. Moreover, the shape of the vertical groove 25a
and the tip end portion shape of the pin 16 to be engaged therewith
can be a simple shape (linear shape) so that the production of
components can be facilitated.
[0125] Furthermore, although the rock of the pin part 25b is
converted to the linear lateral oscillation of the lateral
oscillation transmitting member 26 in this embodiment, it is also
possible to fix the pin part 25b and the lateral oscillation
transmitting member 26, rock the lateral oscillation transmitting
member 25, and have arc-like oscillation of the blade 20. Moreover,
as shown in FIG. 12, the rock transmitting member 25 can be
eliminated.
[0126] Furthermore, the rock transmitting member 25 needs to rock
with oscillation with a lateral direction component for oscillating
the blade 20 in the lateral direction, and therefor, the axial line
L to be the center of the rock should be provided at a position
offset from the rotation central axis of the shaft 15. For the
efficient conversion of the rotation of the shaft 15 into the
oscillation of the lateral direction component, it is preferable
that the axial line L to be the center of the rock is in the same
plane as the rotation central axis of the shaft 15, and further, it
is preferable that the axial line L as the rocking center is
disposed in the plane in the vertical direction passing through the
rotation central axis of the shaft 15 with respect to the lateral
direction for oscillating the blade 20, and the rock transmitting
member 25 is rocked with the axial line L as the center. The
conversion efficiency of the oscillation in the lateral direction
can be most efficient by providing the axial line L orthogonal to
the rotation central axis of the shaft 15 as in this
embodiment.
[0127] Moreover, the vertical groove 25a formed in the rock
transmitting member 25 can be provided at the grip portion 1a side
with respect tot he rotation center of the shaft parts 25c.
Furthermore, by changing the distance of the vertical groove 25a
and the distance of the pin 25b from the rotation center of the
shaft parts 25c, respectively, the width of the lateral oscillation
of the blade 20 with respect to the eccentric amount of the pin 16
can be adjusted freely (it is also possible to enlarge the
oscillation width with a small eccentric amount).
[0128] Moreover, although explanation has been given with the motor
12 for rotating the shaft 15 in this embodiment, an air turbine can
be used as well. Furthermore, as the mechanism for feeding the
blade, a mechanism for incising the cornea by rotational movement
of the blade as disclosed in JP-A-11-19115 and JP-A-11-99167 filed
by the present inventor can be adopted as well.
[0129] As heretofore explained according to the invention, a good
flap can be formed by preventing the "rampage" of the blade.
[0130] Moreover, the lateral oscillation of the blade can be
generated efficiently, the cost rise according to the high accuracy
of the mechanism can be restrained, and the durability of the
mechanism is improved so as to prolong the life cycle.
* * * * *