U.S. patent number RE35,421 [Application Number 08/280,673] was granted by the patent office on 1997-01-07 for automatic corneal shaper.
Invention is credited to Sergio Lenchig G., Luis A. Ruiz.
United States Patent |
RE35,421 |
Ruiz , et al. |
January 7, 1997 |
Automatic corneal shaper
Abstract
The invention relates to a mechanical device for performing
automatic lamellar corneal resections, in particular, myopic
keratomileusis-in-situ and Hyperopic Lamellar Keratotomy. The
device includes three major components, a motor and transmission
assembly, a shaper head assembly and an eyeball retaining ring. The
motor and transmission assembly includes a flexible shaft with a
threaded end which is rotated by an electric or turbine motor. The
threaded end of the shaft drives a helicoidal pinion on the shaper
head assembly which changes the shaft direction by 90.degree.. The
shaper head assembly is moved across the rack of the eyeball
retaining ring by a series of pinions. The device provides a means
for automatically, precisely and safely performing corneal
resections.
Inventors: |
Ruiz; Luis A. (Manakin Sabot,
VA), Lenchig G.; Sergio (Bogota, CO) |
Family
ID: |
23905021 |
Appl.
No.: |
08/280,673 |
Filed: |
July 27, 1994 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
479692 |
Feb 14, 1990 |
05133726 |
Jul 28, 1992 |
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Current U.S.
Class: |
606/166 |
Current CPC
Class: |
A61F
9/013 (20130101) |
Current International
Class: |
A61F
9/013 (20060101); A61F 9/007 (20060101); A61B
017/32 () |
Field of
Search: |
;606/166,161 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Lamellar Refractive Keratoplasty, Bores Eye Institute 1988, 1989,
Chapter 4, pp. 1-9. .
Steinway Instrument Company, Inc., The Steinway/Barraquer In-Situ
Microkeratome Set, Brochure. .
New Methods in Refractive Corneal Surgery--An Experimental Study,
by J. Draeger et al., Klin. Mbl. Augenheilk., 192 (1988), pp.
458-461. .
A Semi-Automatic Electric Keratome for Lamellar Corneal Graft, by
J. Draeger, Klin. Mbl. Augenheilk. 167 (1975) pp. 353-359..
|
Primary Examiner: Thaler; Michael H.
Attorney, Agent or Firm: Beveridge, DeGrandi, Weilacher
& Young, LLP
Claims
We claim:
1. An automatic mechanical device for performing lamellar corneal
resections comprising:
a driving means,
a mobile means connected to said driving means, said mobile means
including a cutting means for performing corneal resections,
an eyeball retaining means .[.movably.]. connected to said mobile
means so that the .Iadd.mobile means is moveable with respect to
said eyeball retaining means and so that the .Iaddend.resection can
be made with precision, and
a transmission means connected to said driving means to provide
simultaneous lineal and transverse oscillatory motion to said
cutting means to automate lineal and transverse driving of the
cutting means during the resecting operation,
wherein the driving means comprises an electric or turbine motor
and said transmission means includes a flexible transmission shaft,
said flexible transmission shaft including a shaft point that
connects to said mobile means, said shaft point having a threaded
area forming an endless pinion, and a tip of said shaft point being
provided with an eccentric, said threaded area transmitting lineal
motion to said mobile means, and said eccentric transmitting
transverse oscillatory motion to said cutting means in a direction
perpendicular to said linear motion.
2. An automatic mechanical device for performing lamellar corneal
resections comprising:
a driving means,
a mobile means connected to said driving means, said mobile means
including a cutting means for performing corneal resections,
an eyeball retaining means .[.movably.]. connected to said mobile
means so that the .Iadd.mobile means is moveable with respect to
said eyeball retaining means and so that the .Iaddend.resection can
be made with precision, and
a transmission means connected to said driving means to provide
motion to said cutting means to automate the resecting
operation,
wherein said mobile means comprises an upper body carrying said
transmission means, said upper body having a cylindrical threaded
area, cut straight on the underside, a cylindrical hole through
said cylindrical threaded area into which a shaft point of said
transmission shaft is introduced, an essentially rectangular-shaped
cavity whose shorter sides are curved, wherein two pins project
from the straight-cut part of said threaded cylindrical area; a
sliding skate on which said upper body with said cutting means is
mounted, said sliding skate including a sliding skate threaded
area, with a straight cut that follows an inclined plane with
respect to a base of said sliding skate, a recess with a transverse
section identical to said cavity of said upper body, said base
being formed by dovetail tracks along the length of said sliding
skate and a rectangular-shaped opening having at the top two
parallel rectangular grooves along the length of said sliding
skate, two small holes in the straight-cut part of said threaded
area which receive said pins of the threaded area of said upper
body; a nut that screws on over the complete thread formed by the
threaded areas when the upper body is mounted on the sliding skate;
a plate that slides in through said opening and along said two
grooves, said plate having a boss shaped like a rectangular
parallelepiped with two holes in the side walls that fit together
with the fixing means in the sliding skate; said fixing means
including two screws, two springs and two balls protruding from the
linear side walls of said opening in said sliding skate.
3. The automatic mechanical device of claim 2, wherein said
transmission means includes a pinion-shaft that engages said
threaded area of said shaft end of said transmission shaft changing
the direction of the axis of rotation, said pinion-shaft running
through said upper body and protruding at each end through opposite
side walls of said upper body; two first pinions directly
connected, one to each end of said pinion shaft; two first shafts
forced in said side walls and bearing at their free ends two second
pinions mechanically coupled with said first pinions; two second
shafts forced in said side walls and bearing at their free ends two
third pinions mechanically coupled with said second pinions.
4. The automatic mechanical device of claim 3, wherein said eyeball
retaining means includes a circular retaining ring assembly with a
central hole which is concentric with the outer edge of the ring
and which accommodates the cornea of the patient undergoing
surgery, said retaining ring including an upper ring with two
parallel toothed tracks which engage said two third pinions of said
transmission means and on which said mobile means will move during
the resection procedure, taking said cutting means across the
cornea, wherein said eyeball retaining means further includes an
inner ring threaded on the outside and an outer ring threaded on
the inside to set and screw said outer ring onto said inner
ring.
5. The automatic mechanical device of claim 2, wherein said cutting
means includes a blade holder having a rectangular parallelepiped
shape with rounded corners, three horizontal slots in one of its
broad faces, a vertical slot in a face opposite to the face with
said three slots, said vertical slot receiving said eccentric of
said shaft end to impart transverse oscillatory motion to said
cutting means, a boss that is C-shaped in the center with two
circles, one above and one below the C; an essentially rectangular
shaped blade made of surgical stainless steel with the cutting edge
along one of its longer sides and with a hole on the inside that is
essentially rectangular in shape, wherein the smaller opposite
sides of the essentially rectangular hole are curved and match said
boss of said blade holder; said blade holder and said blade being
fitted together and inserted in said cavity of said upper body.
6. An automatic mechanical device for performing lamellar corneal
resections comprising:
a driving means,
a mobile means connected to said driving means, said mobile means
including a cutting means for performing corneal resections,
an eyeball retaining means .[.movably.]. connected to said mobile
means so that the .Iadd.mobile means is moveable with respect to
said eyeball retaining means and so that the .Iaddend.resection can
be made with precision, and
a transmission means connected to said driving means to provide
simultaneous lineal and transverse oscillatory motion to said
cutting means to automate lineal and transverse driving of the
cutting means during the resecting operation,
wherein said eyeball retaining means includes a circular retaining
ring assembly with a central hole which is concentric with the
outer edge of the ring and which accommodates the cornea of the
patient undergoing surgery, said retaining ring including an upper
ring with two parallel toothed tracks which engage a pair of
pinions of said transmission means and on which said mobile means
will move during the resection procedure, taking said cutting means
across the cornea, and wherein said eyeball retaining means
includes an inner ring threaded on the outside and an outer ring
threaded on the inside.
7. An automatic mechanical device for performing lamellar corneal
resections comprising:
a driving means,
a mobile means connected to said driving means, said mobile means
including a cutting means for performing corneal resections,
an eyeball retaining means .[.movably.]. connected to said mobile
means so that the .Iadd.mobile means is moveable with respect to
said eyeball retaining means and so that the .Iaddend.resection can
be made with precision, and
a transmission means connected to said driving means to provide
simultaneous lineal and transverse oscillatory motion to said
cutting means to automate lineal and transverse driving of the
cutting means during the resecting operation,
wherein the driving means comprises an electric or turbine motor
and said transmission means includes a transmission shaft, said
transmission shaft including a shaft point that connects to said
mobile means, said shaft point having a threaded area forming an
endless pinion, and a tip of said shaft point being provided with
an eccentric, said threaded area transmitting lineal motion to said
mobile means, and said eccentric transmitting transverse
oscillatory motion to said cutting means in a direction
perpendicular to said linear motion.
8. An automatic mechanical device for performing lamellar corneal
resections, comprising:
a driving means,
a mobile means connected to said driving means, said mobile means
including a cutting means for performing corneal resections,
an eyeball retaining means .[.movably.]. connected to said mobile
means so that the .Iadd.mobile means is moveable with respect to
said eyeball retaining means and so that the .Iaddend.resection can
be made with precision, and
a transmission means connected to said driving means to provide
simultaneous lineal and transverse oscillatory motion to said
cutting means to automate lineal and transverse driving of the
cutting means during the resecting operation,
wherein said eyeball retaining means includes a circular retaining
ring assembly with a central hole which is concentric with the
outer edge of the ring and which accommodates the cornea of the
patient undergoing surgery, said retaining ring including an upper
ring with at least one toothed track which engages at least one
pinion of said transmission means and on which said mobile means
will move during the resection procedure, taking said cutting means
across the cornea, and wherein said eyeball retaining means
includes an inner ring threaded on the outside and an outer ring
threaded on the inside. .Iadd.
9. A device as recited in claim 1 wherein said transmission means
includes a first component in driving engagement with the threaded
area of said shaft point and directly supported by said mobile
body, and said transmission means further comprising a second
component located directly at said eyeball retaining means.
.Iaddend..Iadd.10. A device as recited in claim 7 wherein said
transmission means includes a first component in driving engagement
with the threaded area of said shaft point and directly supported
by said mobile body, and said transmission means further comprising
a second component located directly at said eyeball retaining
means. .Iaddend..Iadd.11. An automatic microkeratome device for
performing lamellar corneal resections comprising:
an eyeball retainer including an aperture through which a portion
of the cornea is exposed, a guideway defining a linear path, and a
first drive element;
a mobile body movably mounted on said eyeball retainer, said mobile
body including at lease one follower element engaging said guideway
to guide said mobile body along said linear path and across said
aperture;
a blade mounted to said mobile body for movement therewith along
said linear path, said blade having a cutting edge extending
outward from said mobile body for resecting a portion of said
cornea as said mobile body moves across said aperture;
a plate member including a bottom face extending forwardly beyond
said cutting edge of said blade to contact said cornea prior to
said cutting edge, said cutting edge being spaced downward relative
to said bottom face of said plate member such that a vertical space
is defined therebetween, said defined vertical space setting the
depth of the corneal resection;
a second drive element attached to said mobile body and in
engagement with said first drive element;
a power source; and
a transmission coupling operatively coupling said power source to
said first and second drive elements to cause relative movement
between said first and second drive elements to thereby move said
mobile body along said linear path so that said blade resects a
lamellar portion of the
cornea. .Iaddend..Iadd.12. An automatic microkeratome device in
accordance with claim 11 in which said first drive element includes
at least one linear toothed rack fixed along a top surface of said
eyeball retainer, and said second drive element includes at least
one pinion rotatably mounted to said mobile body and engaged with
said toothed rack. .Iaddend..Iadd.13. An automatic microkeratome
device in accordance with claim 11 in which said guideway includes
at least one dovetail shaped rail and said follower includes at
least one dovetail shaped runner in
engagement with said rail. .Iaddend..Iadd.14. An automatic
microkeratome device in accordance with claim 11 in which said
blade is mounted for lateral reciprocating movement relative to
said mobile body, and in which said transmission coupling
operatively couples said power source to said blade to effect said
lateral reciprocating movement of said blade. .Iaddend..Iadd.15. An
automatic microkeratome device in accordance with claim 11 in which
said blade is inclined relative to the direction of motion of said
mobile body along said linear path. .Iaddend..Iadd.16. An automatic
microkeratome device in accordance with claim 11 in which said
power source is an electric motor. .Iaddend..Iadd.17. An automatic
microkeratome device in accordance with claim 11 in which said
power
source is a turbine motor. .Iaddend..Iadd.18. An automatic
microkeratome device for performing lamellar corneal resections
comprising:
a driving means;
a mobile means connected to said driving means, said mobile means
including a cutting means for performing corneal resections, guide
elements, and a drive member;
an eyeball retaining means connected to said mobile means so that
the mobile means is moveable with respect to said eyeball retaining
means and so that the resection can be made with precision, said
eyeball retaining means including an aperture through which a
portion of the cornea to be resected is exposed, linear guideways
connected to said guide elements to guide said mobile means along a
path for resecting the cornea, and a drive element movably
connected to said drive member;
a plate member connected to said mobile means for movement
therewith, said plate member including a lower surface spaced from
said cutting means to engage at least part of the exposed cornea
and define the depth of the resection;
a transmission means connected to said driving means to provide
simultaneous lineal and transverse motion to said cutting means to
automate lineal and transverse driving of said cutting means during
the resecting operation, said transmission means being connected to
said drive member to cause relative movement between said drive
member and said drive element to cause said mobile means to
automatically move across said guideways of said eyeball retaining
means at a substantially uniform rate, and said transmission means
being connected to said cutting means to move said cutting means
transversely relative to said mobile means.
.Iaddend..Iadd.19. An automatic mechanical device for performing
lamellar corneal resections, comprising:
a first transmission sub-assembly which includes a driving shaft
with fitting end;
a mobile body which supports the fitting end of said driving shaft
such that said fitting end is free to rotate;
a cutting member;
a cutting member support to which said cutting member is fixed,
said cutting member support being supported by said mobile body
such that said cutting member support is free to oscillate with
respect to said mobile body, and said cutting member support being
in driving engagement with said driving shaft with said driving
engagement producing an oscillating motion in said cutting member
support and cutting member when said fitting end rotates;
an eye retaining member which includes an aperture through which a
cornea to be operated upon extends through, and said mobile body
being slidingly received by said retaining member;
a second transmission sub-assembly including a first component in
driving engagement with the fitting end of said driving shaft and
directly supported by said mobile body, said second transmission
sub-assembly further comprising a second component located directly
at said retaining member, and said second transmission sub-assembly
being arranged such that rotation of said driving shaft conveys a
driving force to said first component which is in driving
communication with said second component at said retaining member
such that said mobile body slides with respect to said retaining
member and such that the cutting member passes over the aperture
formed in said retaining member, and wherein the driving of said
driving shaft results in a simultaneous oscillation of said cutting
member and sliding of said mobile body with respect to said
retaining member.
.Iaddend..Iadd.20. A device as recited in claim 19, wherein said
fitting end of said driving shaft includes an endless pinion, and
said first component is a pinion shaft rotatably fixed with respect
to said mobile body, and said second component is a first side rack
fixed to said retaining member, and said second transmission
sub-assembly further including at least one pinion member which
receives a driving force from said pinion shaft, is rotatably
supported by said mobile body and is in contact with said first
side rack. .Iaddend..Iadd.21. A device as recited in claim 20
wherein said pinion shaft includes two ends extending to opposite
sides of said mobile body with a first pinion member and a second
pinion member fixed to said ends, said second transmission
sub-assembly further comprising a second side rack positioned on an
opposite side of said mobile body as said first side rack, and said
first pinion member being in driving communication with said first
side rack and said second pinion member being in driving
communication with said second side rack. .Iaddend..Iadd.22. A
device as recited in claim 19 wherein said second transmission
sub-assembly includes a plurality of different sized pinion members
on each side of said mobile body each rotatably supported by
said
mobile body. .Iaddend..Iadd.23. A device as recited in claim 19
wherein said mobile body includes a sliding skate and an upper body
portion removably secured to said sliding skate, said sliding skate
having side edges in sliding engagement with corresponding side
recesses formed in said eye retaining member, and said upper body
including a hole which receives the fitting end of said driving
shaft, and said driving shaft further including an eccentric pin
extending out from said fitting end and into engagement with said
cutting member support, and said cutting member support being
received within a slot formed in said upper body portion.
.Iaddend..Iadd.24. A device as recited in claim 19 further
comprising a lamellar corneal resection defining plate slidingly
received by said mobile body so as to present a planar surface a
distance above the aperture formed in said eye retaining member,
and said mobile body including means to releasably secure said
sliding plate with respect to said mobile body. .Iaddend..Iadd.25.
A device as recited in claim 19 wherein said mobile body is
restricted by said eye retaining member to sliding travel along a
first linear direction and said blade oscillates in
a direction transverse to said first linear direction.
.Iaddend..Iadd.26. An automatic mechanical device for performing
lamellar corneal resections, comprising:
a first transmission sub-assembly which includes a driving
component with a coupling end;
a mobile body which supports the coupling end of said driving
component of said first transmission sub-assembly;
a cutting blade;
a blade support to which said cutting blade is fixed, said blade
support being supported by said mobile body such that said blade
support is free to oscillate with respect to said mobile body, and
said blade support being in driving communication with said driving
component of said first transmission sub-assembly such that an
oscillating motion in said blade is produced when said first
transmission sub-assembly is operating;
an eye retaining member which includes an aperture through which a
cornea to be operated upon extends through, and said mobile body
being slidingly received by said eye retaining member;
a second transmission sub-assembly in driving engagement with said
first transmission sub-assembly, said second transmission
sub-assembly including a first component directly supported by said
mobile body and a second component located directly on said
retaining member, and said second transmission sub-assembly being
directly engaged with said eye retaining member such that said
second transmission sub-assembly pulls said driving component of
said first transmission sub-assembly forward as said second
transmission sub-assembly slides said mobile body with respect to
said eye
retaining member. .Iaddend..Iadd.27. A device as recited in claim
26 wherein said driving component is a shaft rotatably supported by
said mobile body, and said second transmission sub-assembly is
positioned forward, with respect to a lineal travel direction of
said cutting blade, of the coupling end of said shaft such that
said second transmission sub-assembly pulls said shaft forward
across said eye retaining member. .Iaddend.
Description
FIELD OF INVENTION
The present invention is related to medical surgery equipment,
particularly to a mechanical device for performing eye surgery,
specifically Myopic Keratomileusis-In-Situ and Hyperopic Lamellar
Keratotomy. More particularly, the invention is an improvement of
such mechanical devices in that it makes the operation of resection
completely automatic.
BACKGROUND OF THE INVENTION
The latest technical advances in the medical field include the
development over the last 20 years of procedures for operating on
the eyes of patients suffering from myopia or hyperopia. Different
methods and special instruments have been designed for performing
this kind of surgery. One such instrument is a mechanical device
bearing a cutting element for performing the operation of resection
on the cornea of the eye. There are currently a few of these
devices on the market. Known as microkeratomes (MKM), they are
suitable for performing Myopic Keratomileusis-In-Situ and Hyperopic
Lamellar Keratotomy. In all these devices the cutting element is
moved by an electric or turbine motor. This movement is a
transverse motion with respect to the direction of the cutting
path. It is therefore necessary to push the blade-carrying device
manually in order to make the cut. Surgical operations of this kind
are presently performed in this manner, and though they have been
quite successful, they involve some problems yet to be solved.
To obtain a precise correction of a visual defect, the dimensions
of the resection that is made must be very precise. Since resecting
is done manually, the precision of the resection depends on factors
difficult to control, such as the pressure exerted by the surgeon's
hand on the instrument and hence on the patient's eye, or the speed
with which he pushes the instrument and its blade to make the
resection. The higher the speed, the thinner the section will be,
resulting in hypocorrection, and the lower the speed, the thicker
the resection will be, resulting in hypercorrection. Moreover,
since the sliding parts of the mechanical instrument are finely
adjusted, irregular pressure or speed applied by the surgeon to the
instrument may cause it to bind. The cutting would then be
irregular and would produce irregular astigmatism in the patient's
eye. Likewise, irregular pressure on the instrument and on the eye
will affect the dimension of the resection.
OBJECTS OF THE INVENTION
One objective of this invention is to provide a mechanical device
capable of performing eye surgery, that has a uniform cutting speed
minimizing pressure changes on the eye. This device is pushed along
by a force of sufficient magnitude evenly distributed so that the
resection will be precise and the instrument will not bind along
its cutting path.
A second objective is to provide a mechanical instrument capable of
performing corneal resections in a completely automatic fashion, so
that the "cleanness" of the cut will not be affected by the
surgeon's hand.
SUMMARY OF THE INVENTION
This invention consists of an apparatus or device made up of three
main parts: a motor and transmission shaft assembly, the shaper
head assembly, and a retaining ring assembly. The device is
specifically designed to perform corneal resections, which are
specialized surgical operations in the medical area of
ophthalmology. Automation of the device includes making the shaper
head assembly move automatically and smoothly at a constant speed
across the retaining ring assembly, which holds the eye in position
for resection. The function of the motor and transmission shaft
assembly is to impart and transmit a uniform mechanical motion, by
a means of transmission, both to the cutting blade in the shaper
head assembly and to the shaper head assembly. The transmission
.Iadd.means .Iaddend.causes said .Iadd.blade .Iaddend.to oscillate
transversally at a constant rate, and it causes the shaper head
assembly to move longitudinally, smoothly and at a constant speed
across the retaining ring assembly and thus across the cornea,
therein making the desired resection.
For a better understanding of the invention, a detailed explanation
of the same is given below with reference made to the attached
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the mechanical device of this
invention.
FIGS. 2, 2A and 2B are the top view, longitudinal section, and
front view, respectively, of one end of the transmission shaft.
FIGS. 3, 3A and 3B are the front, lateral and bottom elevations of
the pinion-bearing upper body of the shaper head assembly.
FIGS. 4, 4A and 4B are the front, lateral and top elevations of the
blade holder.
FIGS. 5, 5A and 5B are the front, lateral and top views of the
cutting element or blade.
FIGS. 6, 6A and 6B are the lateral elevation, cross section, and
bottom elevation of the nut that fastens together the upper
pinion-bearing body and the sliding skate of the shaper head
assembly.
FIG. 7, 7A and 7B are the front, top and lateral elevations of the
sliding skate.
FIGS. 8, 8A and 8B are the front, top and lateral elevations of the
plate, whose thickness determines the thickness of resection.
FIG. 9 is a perspective view of the retaining ring assembly of this
invention.
FIGS. 9A, 9B, 9C, 9D, 9E, 9F, 9G, 9H and 9J show the component
parts of the retaining ring assembly of FIG. 9.
FIG. 10 is a sketch of the mechanical device in the process of
performing a corneal resection on an eye.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
A description is given in this section, which reference to the
attached drawings, of the mechanical device of this invention,
which is capable of performing eye surgery of the resection type
shaping, or myopic and Hiperopic shaping.
The mechanical device 10, specifically designed to perform surgical
operations on eyes to correct for myopia and hyperopia, is shown in
perspective, as a complete unit, in FIG. 1. The device is drawn in
said FIG. 1 as though it were transparent, to reveal several of its
essential internal parts. Said mechanical device 10 is basically
made up of the following main component parts.
The motor and transmission shaft assembly 20, the figure shows only
the end of the transmission shaft that fits into the upper body 30,
this end of the shaft being the only part of said assembly of
interest to this invention. No description will be given of the
motor and the rest of the shaft because they are well-known
elements of the prior art and do not form part of this
invention.
An upper body 30, which comprises a means of transmitting motion to
the cutting element 50 (see also FIGS. 5, 5A and 5B).
A sliding skate 70, to which the upper body 30 is immovably fitted,
and which in turn is fitted onto the fixation ring 90 in such a way
as to be free to slide across it.
A plate 80, which slides into said skate 70 up to a predetermined
fixed position. Said plate 80 defines the thickness of the
resection.
A fastening nut 60, whose function is to hold the upper body 30 and
said sliding plane 70 immovably joined together, these two parts
together forming the shaper head.
A retaining ring assembly 90, whose function in the apparatus as a
whole is to fix the eye in position and at the same time to provide
a fixed support along which the shaper head will slide to resect
the corneal disc with the blade 50. The blade 50 is fitted into the
blade holder 40, which in turn .Iadd.is .Iaddend.inserted into said
upper body of the shaper head. This retaining ring is able to work
with or without vaccum or with pressure only.
Following the above general identification of the main parts of
said mechanical device 10, a detailed description is given below of
each one of them to explain how the device works and thus make
clear the object and scope of this invention.
FIGS. 2, 2A and 2B show the end of the transmission shaft of the
motor and transmission shaft assembly 20. At the extreme end of the
shaft end 28 there is a threaded area 22 working as an endless
pinion, and at the very tip projects a small spindle that is
parallel to but not concentric with said shaft 28; this spindle
will hereafter be referred to as the eccentric 21. No description
will be given of the other parts of the transmission shaft, for
they are well known parts in the .[.ant.]. .Iadd.art .Iaddend.of
flexible shafts; such parts include jacket 29 and other components.
Said shaft end 28 is introduced through a hole in the threaded area
35 (see FIGS. 3A and 3B) of the upper body 30 (see FIG. 1) and
moved further into said body. Once said shaft point 28 is in place
it becomes mechanically connected in its threaded area 22 to a
pinion-shaft 31 (see, FIG. 1) that changes the direction of the
axis of rotation by 90.degree. with respect to the transmission
shaft 20. Rotation is imparted to said pinion-shaft 31 upon mutual
engagement of the two, that is the threaded area 22 of the
transmission shaft and the threaded area of the pinion-shaft 31.
The eccentric 21 fits into a vertical slot along the body of the
blade holder 40. An oscillating motion is imparted to said blade
holder 40 by the eccentric 21 as the eccentric revolves with the
transmission shaft. (See FIG. 1).
Said upper body 30 is shown in detail in FIGS. 3, 3A, and 3B, and
is manufactured out of surgical-grade stainless steel. Said upper
body has a cylindrical threaded area 35 that is cut straight on the
underside and has a cylindrical hole through which is inserted the
shaft end 28 referred to above; a pinion-shaft 31, which engages to
said threaded area 22 of said shaft end 28, said pinion shaft 31
runs through said upper body, juts out of the opposite lateral
walls of said body, and is connected at each end to a pinion 32. In
each one of said lateral walls of said upper body there are two
forced in-shafts fitted with pinions 33 and 34, pinion 33 being
engaged with pinion 32 and being larger in diameter, while pinion
34 being engaged with pinion 33 and being in turn larger in
diameter. The relationship between the diameters of the set of
pinions being chosen according to the required blade advancing
speed. Toward the central part of the upper body, on the underside,
there is a cavity 37 with a rectangular section and rounded ends.
The blade holder 40 fits into this cavity 37. On the straight-cut
part of the threaded area 35, toward the beginning of the thread on
the body, there are two protruding pins 36 whose function will be
understood from the description of the sliding skate 70 given
below.
FIGS. 4, 4A and 4B show the blade holder 40, which has the shape of
a rectangular parallelepiped with rounded corners, comprising on
one of its wider faces three horizontal, triangular wedge-shaped
slots. On the opposite side, the vertical slot referred to above is
located. This is the vertical slot into which the eccentric 21 will
be inserted to impart the transverse oscillatory motion to said
blade holder 40. On the top side of the blade holder (see FIGS. 4
and 4B) there is a boss shaped like an inverted "C" in the center,
with two circles above and below the "C " (see hatched area in FIG.
4B).
The function of said boss is to receive the blade 50 shown in FIGS.
5, 5A and 5B. Toward the center of said blade there is an
essentially rectangular-shaped hole with rounded ends that fits
perfectly onto the boss of the blade holder 40. Said blade holder
is then introduced into said cavity 37 in the upper body 30 in such
a way that the blade is held parallel to the underside of the upper
body 30.
Said upper body 30 is then joined to the sliding skate 70 shown in
FIGS. 7, 7A and 7B. The sliding .[.plane.]. .Iadd.skate .Iaddend.70
has a threaded area 74 which has a straight cut and which follows
and inclined plane with respect to the plane formed by the
dovetails 76. On said plane there is a rectangular-shaped recess 77
with rounded ends like cavity 37 in the upper body 30. Said upper
body 30, with all its elements described above duly assembled, is
so placed that the cut face of the threaded area 35 coincides with
the cut face of the threaded area 74 of the sliding skate 70. In
this way the two pins 36 on the body 30 are inserted into the two
holes 78 provided in the sliding skate, and the blade holder 40
coincides with the recess 77 so that the cutting element 50 becomes
duly secured. Then the two parts, the upper body 30 and the sliding
skate 70, are fixed together as a single unit by screwing on the
fastening nut 60 over the thread formed by the threaded parts 35
and 74. The blade is thus in the proper position for making a
resection; although free to move transversally because the length
of the cavity 37 in the upper body 30 is somewhat greater than the
length of the blade holder 40.
With reference again to FIGS. 7, 7A and 7B, two parallel slots 75
can be seen above a rectangular-shaped opening in the body of the
sliding skate 70. Plate 80 is inserted into said opening in a
sliding manner along said slots 75 (see FIG. 1). The thickness of
the plate determines the depth of resection, thus a resection of
predetermined depth can be made by using a plate of appropriate
thickness. FIGS. 8, 8A and 8B show the general form of plate 80.
FIG. 8B highlights a part of the plate that is shaped like a
rectangular parallelepiped and has two circular holes 82. These
holes serve to retain plate 80 in position in the sliding skate 70
when the holes fit over the spheres 71 located in the body of the
sliding skate 70. The springs 72, which are held in place by the
screws 73, keep said spheres pressed outward.
All the parts described above make up the mobile means of the
mechanical device once they are assembled together. This mobile
means is the cutting instrument. (See FIG. 10).
The fixed part or support of the mechanical device is the retaining
ring assembly 90, which is shown in FIG. 9. As can be seen, it is
circular in shape and has a circular concentric hole 98. When said
retaining ring assembly 90 is placed over the patient's eyeball,
the cornea will appear centered on said hole 98 and protruding
through it. FIGS. 9D, 9E and 9F show an upper ring 96 with two
parallel toothed tracks 91 on it which run across ring 90 along the
sides of hole 98. FIG. 9E shows two V-shaped grooves 94 that run
parallel to the tracks 91. The dovetails 76 of the sliding skate 70
(see FIG. 7) are inserted into these grooves 94 in such a way that
each one of the tracks 91 engages one of the pinions 34 of the
upper body 30.
With reference again to FIG. 9, a description is given below of the
retaining ring assembly 90, which comprises three components:
A slender upper ring 96 that has the hole 98, the tracks 91, the
grooves 94 and two small holes 99 (see FIGS. 9D, 9E and 9F).
An inner ring 95 that has an outer thread and two pins 92 which
will be inserted into the holes 99 in the upper ring 96. The inside
of said ring 95 is shaped like a circular seat in which the
patient's eyeball will be adjusted (see FIGS. 9A, 9B and 9C).
An outer ring 97 with an inner thread that serves to hold together
the two preceding rings, the three together forming the complete
eye retaining ring assembly (see FIGS. 9G, 9H and 9J).
The apparatus is thus ready to fulfill its purpose of resecting the
cornea of the patient's eye.
Next, the transmission shaft is connected by inserting the shaft
end 28 (FIGS. 2 and 2A) through hole 38 in the upper body 30 until
the eccentric 21 enters the vertical slot of the blade holder 40
and the threaded area 22 of the shaft end 28 engages the pinion
shaft 31 (see FIGS. 3, 3A, 4B and 1).
It only remains now to start the motor for the resection to be made
automatically, precisely and safely (see FIG. 10). The high degree
of resecting precision obtained in this way ensures that the
patient under treatment will receive the required visual
correction.
It is to be understood that the above description of the invention
is made to exemplify the preferred embodiment and in no way limits
the scope of this invention. One skilled in the art will realize
that it is possible to make modifications or variations without
departing from the spirit or scope of this invention.
* * * * *