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FIELD OF THE INVENTION
This invention relates to a pupil dilator and, more particularly, to an
instrument for dilating the pupil of the human eye so that the lens can be
accessed for cataract surgery.
BACKGROUND OF THE INVENTION
In cataract surgery the pupil of the eye must first be dilated so that the
surgeon has access to the lens. In many cases, conventional pupil dilating
drugs are ineffective for this purpose. For example, if the patient has
been undergoing glaucoma treatments he or she may very well have been
using a myotic drug. Prolonged use of such medication tends to make the
pupil fibrotic and resistant to dilation. Accordingly, in such cases, the
cataract surgeon must mechanically dilate the pupil prior to surgery.
Conventional techniques for mechanically dilating the pupil exhibit various
disadvantages. Typically, known mechanical dilators employ an intricate
construction and are often quite difficult for the surgeon to manipulate
and set in place. For example, in one technique, four retractors are
surgically implanted into the eye. Each retractor includes a hook that
holds a corner of the pupil in such a way that a square opening is
created. In addition to being time consuming, complicated and expensive,
this technique requires that four incisions be made in the eyeball.
Precise manipulation of the iris is also required.
In another known technique, a water absorbent ring is inserted into the
pupil. As the ring absorbs liquid and expands, it conforms to the shape of
the pupil and causes it to dilate. This ring is difficult to introduce
into and remove from the pupil. Additionally, it needs to be precisely
manipulated in the eye by the surgeon.
SUMMARY OF INVENTION
It is therefore an object of this invention to provide an improved
instrument for dilating the pupil of the human eye so that the lens is
accessible for cataract surgery;
It is a further object of this invention to provide a mechanical pupil
dilator that is quickly and conveniently introduced into the pupil of the
eye and operated by the surgeon to open the pupil a desired amount;
It is a further object of this invention to provide a mechanical pupil
dilator that employs a relatively simple, yet effective construction;
It is a further object of this invention to provide a mechanical pupil
dilator that effectively opens the pupil without requiring additional
incisions in the eye.
This invention features an instrument for dilating the pupil of an eye,
including a handle and switch means mounted on the handle for alternating
between first and second states. A retractable dilator mechanism is
attached to the switch means and is extendible from the handle. The
dilator mechanism selectively alternates between a retracted condition
when the switch means are in a first state and an expanded condition when
the switch means are in the second state. Engagement means are carried by
the dilator mechanism for engaging a plurality of points along an inside
edge of the pupil and urging the pupil into a dilating condition when the
dilator mechanism is expanded.
In a preferred embodiment the switch means include a manually engageable
switch element that is slidably mounted on the handle. The handle may
include an internal channel that slidably receives at least a portion of
the dilator mechanism and a longitudinal groove connected to the internal
channel for receiving the switch element.
The dilator mechanism may include a plurality of elongate arms. The
engagement means may include hook elements that are respectively secured
to the distal end of each arm. The arms may be longitudinally slidably
receivable in a tubular sheath that is secured to and extends from the
handle. The arms retract into the sheath when the switch means are moved
into the first state and expand out of the sheath when switch means are
moved into the second state. A plurality of such arms may be resiliently
curved such that the arms expand radially when they are extended out of
the sheath and contract radially when the arms are retracted into the
sheath. The dilator mechanism may include an elongate shaft that
interconnects the switch means and the elongate arms. The shaft is
slidably receivable in the channel and the tubular sheath. A tensioning
hook may be carried by the sheath for engaging and tensioning the pupil
when the dilator mechanism is expanded.
In an alternative embodiment, the dilator mechanism may comprise an
elongate ribbon that is attached to the switch element and slidably
received in a guide that is attached to the handle. The ribbon may have a
distal end that is attached to a distal portion of the handle and a loop
section that is formed beyond the distal end of the handle. The engagement
means are preferably defined by the loop portion of the ribbon.
In another alternative embodiment, the dilator mechanism may include a
piston that is mounted in the handle and responsive to movement of the
switch member. The dilator mechanism may also include a pneumatic cylinder
for operably receiving the piston, a selectively inflatable and deflatable
coil element and a pneumatic conduit interconnected between the cylinder
and the coil element. In the first switch state, the piston is retracted
in the cylinder and the coil element is collapsed. In the second switch
state, the piston compresses air in the cylinder and the coil element is
expanded. In this embodiment, the engagement means are preferably defined
by an outer surface of the coil element.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Other objects, features and advantages will occur from the following
description of preferred embodiments and the accompanying drawings, in
which:
FIG. 1 is a plan view of a preferred pupil dilating instrument according to
this invention;
FIG. 2 is an elevational side view of the instrument of FIG. 1;
FIG. 3 is a plan view of the retractable dilator mechanism employed in the
instrument of FIGS. 1 and 2;
FIG. 4 is an elevational side view of the mechanism of FIG. 3;
FIG. 5 is an elevational cross sectional view of the instrument of FIGS. 1
and 2;
FIG. 6A is an elevational plan view of the forward end of the dilator
instrument inserted in the undilated pupil of a human eye and with the
dilator mechanism fully retracted;
FIG. 6B is a view, similar to FIG. 6A, of the dilator mechanism in a
partially expanded condition with the hook elements engaging the inside
edge of the pupil of an eye;
FIG. 7 is a view, similar to FIG. 6A, of the dilator instrument engaging
the pupil of an eye and with the dilator mechanism in a fully expanded
condition, which dilates the pupil.
FIG. 8A is a plan view of an alternative pupil dilating instrument
according to this invention, wherein a thin ribbon is employed as the
dilator mechanism;
FIG. 8B is an elevational side view of the instrument of FIG. 8A;
FIG. 9 is an elevational view of the switch and ribbon guide used in the
instrument of FIGS. 8A and 8B;
FIG. 10 is a plan view of the leading end of the instrument of FIGS. 8A and
8B inserted in a pupil of the human eye and maintaining a collapsed or
retracted condition prior to the dilation of the pupil;
FIG. 11 is a view similar to FIG. 10 of the dilating instrument in an
expanded condition, which dilates the pupil;
FIG. 12 is a plan view of another alternative pupil dilating instrument
according to this invention, which instrument employs a pneumatically
operated dilator mechanism;
FIG. 13 is an elevational, side view of the instrument of FIG. 12.
FIG. 14 is a plan view of the coil element that is utilized as the dilator
mechanism of FIGS. 12 and 13, which element is in a uninflated, retracted
condition.
FIG. 15 is a plan view of the instrument of FIGS. 12-14 with the deflated
coil element introduced into the pupil of an undilated eye; and
FIG. 16 is a view similar to that shown in FIG. 15 but with the coil
element in s pneumatically expanded condition, which causes the pupil to
dilate.
There is shown in FIGS. 1 and 2 a mechanical pupil dilating instrument 10.
The instrument includes an elongate handle 12 and an elongate tubular
sheath 14 that is attached to and extends from the forward end of handle
12. A thumb activated switch 16 is movably mounted to handle 12. In
particular, switch 16 engages handle 12 through a longitudinal groove 18
formed in the handle. Switch 16 is slidable between a first state or
position at the rearward end of groove 18 and a second state or position
at the forward end of the groove. As is described more fully below, the
switch is attached 20 inside of handle 12 to a retractable dilator
mechanism. The dilator mechanism extends from the forward end of the
handle through sheath 14 and emerges from the distal end of the sheath.
Dilator mechanism 20 includes three resilient wires 22, 24 and 26, which
engage the pupil to be dilated. The precise construction and operation of
these elements is explained more fully below.
Handle 12 comprises a pair of molded plastic portions 28 and 30. The switch
and sheath may similarly comprise durable yet light weight plastics or
other materials that are commonly used for surgical instruments. The
handle may comprise configurations other than that shown and may exhibit a
one piece or other multiple piece construction.
Retractable dilator mechanism 20 and attached thumb switch 16 are
illustrated in greater detail in FIGS. 3 and 4. The dilator mechanism
includes an elongate shaft 30 that is preferably composed of a plastic or
other synthetic material. Resilient wires 22, 24 and 26 are secured to a
forward end of shaft 30. The ends of the wires proximate shaft 30 are
juxtaposed and aligned. Central wire 24 extends in an linearly for its
entire length. Adjacent wires 22 and 26 diverge in a generally Y-shaped
configuration from wire 24 prior to their distal ends. Wires 22 and 26 are
provided with a spring bias that causes them to diverge from the axis
defined by wire 24. The degree of divergence is determined by the length
of wires 22, 24 and 26 exposed from sheath 14, FIGS. 1 and 2. The wire
segments located within the sheath are held together in a non-divergent
condition as shown, for example, by segments 32 in FIG. 3. Any portion of
the mechanism 20 that is exposed from sheath 14 is biased into the
divergent condition. Therefore, the radial size defined by mechanism 20
expands as more of the dilator mechanism is exposed from the sheath.
The distal end of each wire carries a respective engagement means in the
form of a U-shaped hook. Wire 24 carries a hook 34. Similarly, wire 22
carries a hook 36 and wire 26 carries a hook 38. The hooks are quite
small, as illustrated by hook 34 in FIG. 2, so that they are able to
engage an inner edge of the pupil of a patient's eye. A tensioning hook 40
is carried by sheath 14. As described below, hook 40 engages the inside
edge of the patient's pupil as the dilator instrument is operated. This
tensions and helps to dilate the pupil.
Referring to FIGS. 3 and 4, each of the wires 22, 24, and 26 is secured to
shaft 30 such as by embedding the wires into the shaft as it is molded,
appropriate adhesives or in other manners that will be known to those
skilled in the art. Switch 16 is secured unitarily or otherwise to the
opposite end of shaft 30. The switch includes a thumb engaging portion 42
and a slide portion 44. The thumb engaging portion should have a size and
shape such that it is comfortably engageable by the surgeon during a
cataract operation.
As shown in FIG. 5, handle 12 has a longitudinal internal channel 46 that
is communicably interconnected with longitudinal groove 18. Tubular sheath
14 has a central channel 48 that is communicably aligned with channel 46.
Elongate shaft 30 of dilator mechanism 20 extends between channels 46 and
48. Resilient wires 22, 24 and 26 (the latter of which is obscured) extend
from the distal end of shaft 20 through channel 48 emerge from the distal
end of sheath 14. Thumb switch 16 extends upwardly from shaft 30 through
groove 18. Slide portion 44 of switch 16 engages the handle adjacent to
groove 18. As a result, the surgeon operates instrument 10 by engaging
switch 16 and moving the switch forwardly or rearwardly, as required, in
the manner indicated by double headed arrow 50. As switch 16 is moved
forwardly, shaft 30 is pushed toward the distal end of sheath 14. Wires
22, 24 and 26 gradually emerge from sheath 14 and expand in a divergent
manner. Subsequently, the wires may be retracted within the sheath by
pushing switch 16 rearwardly into its opposite state. The resilient wires
22 and 26 collapse as they are gradually drawn into sheath 14.
The opposite end of handle 12 includes a portion 28 that is molded and has
an internal cavity 54. Parts 28 and 30 are secured together either
permanently or provisionally by adhesives, sonic welding, threads or other
known attachment means.
Instrument 10 is used in cataract surgery, as illustrated in FIGS. 6A, 6B
and 7 to expand pupil 60 of eye 58. First, the patient is anesthetized and
prepared for surgery. The surgeon grasps the handle 12 of instrument 10
and pushes switch 16 rearwardly, into its first state, as previously
described, so that the dilator mechanism is fully retracted. In that
condition, the wires are drawn fully into sheath 14, in the manner shown
in FIG. 6A. The surgeon then manipulates instrument 10 and interengages
hook 40 (which is obscured in FIG. 6B) with the inside edge of pupil 60.
Instrument 10 is pulled in the direction of arrow 61 to tension pupil 60.
Engagement hooks 34, 36 and 38 are partly expanded by pushing switch 16 in
a forward direction such that the hooks likewise engage and grip the inner
edge of pupil 60 (FIG. 6B). The small, radially compact size of the wires
makes insertion quick and convenient. After secure engagement is made, the
surgeon slides switch 16 fully forwardly into its second state. This
pushes wires 22, 24 and 26 outwardly from the distal end of sheath 14 in
the manner shown in FIG. 7. At the same time, hook 40 maintains its
engagement with the edge of pupil 60 and tension is maintained in the
direction of arrow 61. The resiliently biased wires 22, 24 and 26 diverge
as indicated by arrows 62. As a result, pupil 60 is opened or dilated. The
surgeon is then able to perform necessary repair or replacement of the
lens. After the pupil 60 is dilated in this manner, instrument 10 is
quickly and conveniently removed from the vicinity of the eye by
retracting wires 22, 24 and 26, as described above, such that the hooks
34, 36 and 38 disengage the edges of pupil 60. During the dilation
process, the fibrosis in the eye is broken. Therefore, the pupil remains
dilated even after the U-shaped hooks and the tensioning hook are
disengaged from the pupil and the wires are retracted. As a result, unlike
many conventional pupil dilators, the instrument does not have to remain
engaged with the eye during cataract or other eye surgery.
FIGS. 8A and 8B illustrate an alternative pupil dilating instrument 110.
The instrument comprises a handle 112 that is formed of molded plastic or
other rugged, yet lightweight material. An elongate metal or plastic guide
113 is mounted longitudinally along the side of handle 112. An elongate
nylon ribbon 115 is received in a space between guide 113 and handle 112.
Ribbon 115 extends beyond a forward end 117 of handle 112 and forms a loop
119. The distal end of nylon ribbon 115 is connected to handle 112 by a
pivot 121.
A switch 116 is slidably mounted to handle 112. As best illustrated in FIG.
9, the switch is attached to nylon ribbon 115 through a longitudinal
groove 118 in ribbon guide 113. As a result, thumb switch 116 is able to
slide back and forth in the direction of double headed arrow 150. Other
alternative means may be employed for slidably mounting switch 116 to
housing 112 and for attaching the switch to the nylon ribbon.
When switch 116 is moved to a rearward position in groove 118, ribbon 115
is retracted in ribbon guide 113 and loop 119 maintains the relatively
small, contracted circular shape shown in FIGS. 8A and 8B. When switch 116
is pushed forwardly, ribbon 115 is driven through guide 113 and loop 119
is expanded and enlarged.
FIG. 10 depicts instrument 110 with loop 119 in a retracted condition. In
this condition, instrument 110 is conveniently manipulated by the surgeon
such that loop 119 is placed within pupil 160 of eye 158. An outer
circumferential surface of loop 119 forms an engagement means which
engages the inner edge of pupil 160. To dilate the pupil, switch 116 is
pushed forwardly relative to handle 112 in the manner described in FIGS.
8A, 8B and 9. This causes loop 119 to expand into the condition shown in
FIG. 11. As a result, pupil 160 is dilated in the manner shown. Switch 116
is then pushed rearwardly to retract loop 119. The dilator is removed from
the pupil and cataract surgery is performed.
A pneumatically powered mechanical dilator 210 is illustrated in FIGS. 12
and 13. Instrument 210 includes a handle 212 and a pneumatic cylinder 251
mounted to an upper surface of handle 212. A thumb switch 216 is slidably
mounted on a track 253 formed on handle 212 adjacent to cylinder 251. A
pneumatic piston 255, shown in phantom, is operably mounted within
cylinder 251. An actuating rod 257 operably interconnects switch 216 and
pneumatic piston 255.
A pneumatic conduit 259, shown in phantom, extends from cylinder 251,
through the forward end of handle 212 and through an elongate extension
piece 263. A fitting 265 at the distal end of extension 263 interconnects
the extension to an inflatable spiral tube 267. In particular, tube 267 is
communicably attached to conduit 259. The spiral tube, shown alone in FIG.
14, may comprise various sterile plastic materials that are suitable for
use in opthamalogical and surgical applications.
Switch 216 is selectively slid back and forth along tracks 253 between a
rearward, first state and a forward, second state. In the first state, rod
257 retracts piston 245 in cylinder 251. As a result, air is not
compressed in the cylinder or the pneumatic conduit. This causes spiral
tube 267 to remain deflated and in the contracted condition shown in FIGS.
12, 13 and 14. Conversely, if switch 216 is slid forwardly into its second
state, piston 255 is driven forwardly in cylinder 251 to compress air in
the cylinder. This causes air pressure to be transmitted through conduit
259 into spiral tube 267. The spiral tube inflates or expands to dilate
the patient's pupil.
Instrument 210 is specifically utilized in the manner shown in FIGS. 15 and
16 in order to dilate pupil 260 of eye 258. Initially, as shown in FIG.
15, instrument 210 is positioned inside eye 258 such that spiral tube 267
is introduced into pupil 260. The contracted condition of tube 267 permits
the dilator instrument to be readily manipulated by the surgeon and
positioned within the pupil. Subsequently, the surgeon actuates the
dilator by sliding switch 216 forwardly. This causes tube 267 to expand,
as previously described, into the condition shown in FIGS. 16. The outer
surface of the spiral tube engages the inner edge of pupil 260. As tube
267 is inflated, it radially expands in the manner shown, to dilate the
pupil. As with each of the instruments described herein, this entire
dilating operation is accomplished almost immediately and does not require
the manipulation and/or surgical insertions required by dilators of the
prior art.
Accordingly, the present invention accomplishes improved rapid dilation of
the pupil so that cataract surgery and other eye procedures can be
performed rapidly and effectively. In each of the embodiments described
herein, time is saved and surgery is facilitated because the surgeon does
not have to perform tedious manipulations and attachments of an instrument
to the pupil. Additionally, the incisions do not have to be made in the
eye to attach the instrument. As in the initially described embodiment,
the instruments of the other embodiments can be removed as soon as
dilation is performed because at that point, the fibrosis in the eye is
broken and the pupil should remain dilated for the duration of the
surgery.
Although specific features of the invention are shown in some drawings and
not others, this is for convenience only, as each feature may be combined
with any or all of the other features in accordance with the invention.
Other embodiments will occur to those skilled in the art and are within
the following claims.
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