WO1996029965A1

WO1996029965A1 - Device for dilating a pupil and/or maintaining a pupil in a dilated state

Info

Publication number: WO1996029965A1
Application number: PCT/AU1996/000170
Authority: WO
Inventors: Edward John Milverton
Original assignee: Milvella Pty. Ltd.
Priority date: 1995-03-27
Filing date: 1996-03-26
Publication date: 1996-10-03

Abstract

A device (26) for dilating a pupil (24) and/or maintaining a pupil (24) in a dilated state. The device (26) includes a generally arcuate body (28) having first and second ends (35). The outer peripheral edge of the body has an engaging formation (30) adapted to engage the inner peripheral edge (22) of an iris (16) to retain the pupil (24) in an expanded state, and at least one positioning arm (34) extending generally outwardly from one of the ends (35) of the body (28) so as to remain external to the eye.

Description

TITLE: "DEVICE FOR DILATING A PUPIL AND/OR MAINTAINING A PUPIL

IN A DILATED STATE"

FIELD OF THE INVENTION

The present invention relates to a device for dilating a pupil and/or maintaining a pupil in a dilated state.

The invention has been developed primarily for use in ophthalmic surgery and

will be described hereinafter with reference to this application. However, it will be

appreciated that the invention is not limited to this particular field of use and can be

utilised in other medical procedures where an opening is required to be expanded and

maintained in the expanded state.

BACKGROUND OF THE INVENTION

It is advantageous in many ophthalmic surgical procedures for the pupil to be dilated as much as possible. A pupil is dilated when the iris retracts towards the outer

edges of the eye. This normally occurs when the eye is deprived of bright light, for

example, at night. When performing ophthalmic operations, such as replacing the lens of a

patient's eye with an artificial intraocular lens, a dilated iris and pupil gives the

surgeon a larger area to manipulate surgical instruments in order to operate on the

human lens. The more area available to the surgeon reduces the risk of damaging the

iris or other components of the eye due to unintentional contact with the surgical

instruments.

A common method of dilating the pupil is the use of chemical eyedrops. The

eyedrops are formulated to trigger the expansion of the iris, resulting in a dilated pupil.

However, such eyedrops are not effective on all patients and more surgically

complicated measures are often required. Also, such eyedrops can "wear off during

an operation resulting in the iris retracting and reducing the pupil size.

One method to dilate and maintain a pupil in the dilated state involves making

four minor incisions at roughly 90° intervals around the periphery of the cornea and

inserting a small hook-like apparatus through each incision. The hooks engage with

the inner circumferential edge of the iris and when retracted, pull the iris outwards to

define an enlarged substantially square shaped opening. Another method, known as a

sphincterotomy, involves making an incision into the cornea through which a blade is

passed that makes radial cuts into the iris itself, thus allowing the iris to dilate and

expose more of the lens. Both the above methods add extra time to the actual

operation being performed and the latter involves considerable risk of damage to the

patients iris. Moreover, the damage done in segmenting the iris during a

sphincterotomy is irreversible and results in a permanently disfigured iris. It is an object of the invention, to overcome or ameliorate at least some of the

deficiencies of the prior art.

SUMMARY OF THE INVENTION

According to a first aspect of the invention there is provided a device for

dilating a pupil and/or maintaining a pupil in a dilated state, said device including a

generally arcuate body having first and second ends, the outer peripheral edge of the

body having an engaging formation adapted to engage the inner peripheral edge of an

iris to retain the pupil in an expanded state, and at least one positioning arm extending

generally outwardly from one of the ends of the body so as to remain external to the

eye.

Preferably, positioning arms are provided at both the ends of the body.

Preferably also, the body is adapted to deform to a generally elongated or

folded configuration able to be passed through an exterior incision in the eye and

resiliently return to a substantially annular configuration engaging the iris edge.

Desirably, the body also includes a guide tab extending outwardly from and

generally parallel to a diameter of the body for aiding insertion of the device, for

supporting the body in engagement with the iris edge and also for preventing the body

from "falling" through the pupil opening.

In a preferred embodiment, the positioning arm or arms each terminate in a

gripping formation. The formation provides a convenient gripping point for the

device and also, if so desired, allows the positioning arms to be sutured to the eye.

The gripping formation or formations may include a hole through which a suture

thread may be passed. In another preferred embodiment, each of the arm or arms include a proximal

portion adjacent the body and an offset distal portion extending to the gripping

formation or formations so as to allow the distal portion or portions to remain external

to the eye and above the level of the iris whilst the device is in use dilating the pupil.

The resilience of the body preferably provides a radially outwardly directed

force capable of urging into and maintaining the body in a substantially annular

configuration whilst engaging the iris to expand and/or maintain the pupil in the

dilated state.

In a preferred form, the engaging formation is desirably formed so as to define

a continuous recessed channel between the ends.

In a further embodiment, the body comprises a pair of circumferentially

aligned parallel axially spaced apart incomplete rings and a series of circumferentially

spaced apart curved joining members extending from one ring to the other to define

said engaging formation.

In another embodiment, the body is provided with a plurality of radially

outwardly angled pairs of flaps, each pair of flaps defining a portion of the recess

therebetween.

The body is preferably made from a material selected from the group including

prolene, poly methyl methacrylate, nylon, silastic, silicon polyimide, polyamide or a

combination thereof, or any other material having the requisite properties of resilience

and suitability for use in surgical procedures.

In a further embodiment, an insert of a second material is contained within the

body to give the required resilience. In a further embodiment, the body is sized to provide an inner diameter in the

substantially annular configuration of between approximately 5.5mm and 7mm, the

body itself has a radial thickness of between about .75 and 1.25mm. In this

embodiment, the recess has an axial depth of about 1.12mm and the guide tab extends

from the outer edge of the body by about 1.25mm. The distal portions of the arms are

preferably offset from the proximal portions by about 1.5 to 2.0mm in the axial

direction.

In yet another embodiment, regions of weakness may be included in the body

to further facilitate resilient deformation between the expanded annular and the

elongated or folded configurations.

Desirably, the device is tinted for increased visibility to the surgeon.

In the annular configuration, the arcuate body has an included angle of

between approximately 270° and 340°.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described, by way of

example only, with reference to the accompanying drawings in which:

Figure 1 is a sectional side view of a human eye;

Figure 2 is a sectional side view of the eye shown in Figure 1 showing the

pupil being maintained in a dilated state by a first embodiment of the device according

to the invention;

Figure 3 is a plan view of the device shown in Figure 2 illustrated in an

annular configuration;

Figure 4 is a side view of the device shown in Figure 3; Figure 5 is a plan view of the device shown in Figure 3 in the elongated or

folded configuration;

Figure 6 is a plan view of a second embodiment of the invention;

Figure 7 is a sectional side view of the device shown in Figure 6;

Figure 8 is a plan view of a third embodiment of the invention;

Figure 9 is a sectional side view of the device shown in Figure 8;

Figure 10 is a plan view of a fourth embodiment of the invention;

Figure 1 1 is a sectional side view of the device shown in Figure 10;

Figure 12 is a plan view of a fifth embodiment of the invention;

Figure 13 is a side view of the device shown in Figure 12; and

Figure 14 is an inverted partial plan view of the device shown in Figure 12.

PREFERRED EMBODIMENTS OF THE INVENTION

Referring to Figure 1 there is shown a human eye having a cornea 10, sclera

1 1, anterior chamber 12. lens 14, iris 16, limbus 17, retina 18 and optic nerve 20. The

iris 16 has an inner peripheral edge 22, the boundary of which defines the opening of

the iris known as the pupil 24 (the black circle in the centre of an eye).

As described previously, it is advantageous during surgery of the eye, for the

pupil opening 24 to be as large as possible to permit access to the lens and other parts

of the eye via incisions in the cornea or sclera.

Referring to Figure 2, there is shown in use a device 26 according to the

invention for dilating the pupil and/or maintaining the pupil in the dilated state. The

device 26 comprises a generally arcuate body 28 having first and second ends 35. The

outer peripheral edge of the body has a recess 30 adapted to engage the inner peripheral edge 22 of the iris to retain the pupil in a dilated state. The device also

includes positioning arms 34 which extend generally outwardly from the ends 35 of

the body and remain external to the eye when the device is in use. The arms are more

clearly shown in Figures 3 and 4. The recess 30 forms a continuous channel 32

between the ends 35. Device 26 also includes guide tab 36 which extends from the

body 28.

Referring to Figures 3 and 4, the arms 34 can each be seen to include a

proximal portion 38 adjacent to the body and a distal portion 40 substantially parallel

to, but offset from the proximal portion 38. The arms 34 terminate in gripping

formations 44.

If desired, the formations 44 also allow the surgeon to suture the arms 34 to the

sclera 11. Holes can be provided through the formations through which the suture

thread may be passed.

Referring in particular to Figure 5, it can be seen that the body 28 is adapted to

resiliently deform to a generally elongated or folded configuration as shown which is

able to be passed through an exterior incision into the eye and, upon release, return to

a substantially annular configuration, as shown in Figure 4. Referring next to Figures

6 to 10, there are shown several alternative embodiments of the device according to

the invention. The embodiment of the device shown in Figures 6 and 7 comprises a pair of

circumferentially aligned parallel axially spaced-apart incomplete rings 46 with a

series of circumferentially spaced-apart joining members 48 extending from one ring

to the other to define the recess 30. The embodiment of the invention shown in Figures 8 and 9 is similar to the

previously illustrated embodiments except that the body 28 is provided with a series of

radially extending flaps 50 around its periphery. Furthermore, this embodiment

includes regions of weakness 52 which facilitate resilient deformation between the

configurations shown in Figure 3 and Figure 5.

Referring now to the embodiment shown in Figures 10 and 1 1, the body of the

device is in the form of a single incomplete annular ring 54 provided with a plurality

of radially outwardly angled pairs of flaps 56. Each pair of flaps defines a portion of

the recess 30 therebetween.

A fifth embodiment of invention is shown in Figure 12 to 14. This

embodiment is similar to those previously described except the distal portions 40 of

each of the arms 34, which remain external the eye during use, are angled slightly

downwardly towards the eye surface to prevent the device from tilting towards the

cornea when the arms are pressed downwards. To allow easier suturing, the gripping

formations 44 are each provided with a pre-formed suture hole 54 which is adapted to

receive suture thread therethrough.

When viewed in plan, the arms 34 are angled slightly outwardly from the

incision which, in addition to the downward angling, provides extra clearance for

instruments passing through the incision. Also, the shape of the arms allows the

device to maintain a snug fit with the eye when in use dilating the pupil.

Additionally, as best shown in the inverted plan view of Figure 14, the body 28

of the device is recessed below the guide tab 36 so as to provide two regions of weakness 52 which facilitate flexure of the device into the elongated position

described previously.

Further, to enhance the withdrawal of the device, the proximal portion 38 of

each of the arms 34 is provided with a smoothly tapered surface 56. This lessens the

likelihood of the device snagging or catching as the device is withdrawn through the

incision.

Referring back to Figure 2, there is shown a tunnel incision 42 used in, for

example, a lens replacement. The circumferential incision begins generally just

behind the limbus 17, is 2.5 to 5.5mm wide, and extends normally into the sclera for

about half it's depth (approximately 0.5 to 0.75mm). The incision then travels through

the sclera and then cornea for approximately 3 to 4mm then again is angled through

the cornea to finally open into the anterior chamber 12.

In use of the device, the incision 42, of approximately 2.5 to 5.5mm in width,

is made through the cornea and/or sclera of the eye. The device 26 is then elongated

or folded so that it can more easily be passed through this tunnel incision into the

anterior chamber 12 of the eye. The device may be inserted in the elongated

configuration by forceps such as angled "Mclntyre" forceps. The forceps grip the

device in recess 30 and so elongate the device for passing it through the incision. The

guide tab 36 aids the insertion process.

Preferably, the anterior chamber is filled with a visco-elastic fluid prior to

insertion of the device. As the device is being passed through the incision, the inner

peripheral edge 22 of the iris is partially located in recess 30. This location is helped by guide tab 36 sliding over, and resting upon, the upper surface of the iris. The guide tab 36 also prevents the device from "falling" through the pupil opening during

insertion.

Once through the incision the resilience of the device then returns it to the

substantially circular configuration shown in Figure 3. As the device fully engages

edge 22 in recess 30 it provides sufficient radial force to expand the iris, thus dilating

the pupil. This radial force is also sufficient to maintain the pupil in the dilated state

shown in Figure 2.

It will be appreciated that due to the small size of both the device and the iris,

that occasionally some misengagement may occur which can be corrected by re-

positioning the device using arms 34. As a portion of each arm remains external to the

eye during pupil dilation, this repositioning can readily be effected. Also, the surgeon

can give additional dilation to the eye by pushing the arms towards the eye centre.

Since the proximal and distal portions, 38 and 40 respectively, are offset axially from

one another, the device can easily be positioned parallel to, and adjacent with, the iris

edge after the proximal portions have passed through the incision in the eye. The

surgical incision is generally offset so as to be above the plane of the iris edge.

The apparatus according to the invention provides several major advantages

over existing methods of dilating pupils. The first is that it will dilate and hold in a

dilated position a pupil that would not otherwise dilate under the influence of eyedrops

and the like. This gives the surgeon the space needed to perform the eye operation

without having to resort to more drastic measures to dilate the pupil. Moreover, since

the device is introduced into the anterior chamber of the eye by a single incision, there

is minimal surgical trauma to the patient. Another advantage is that the device can be introduced through the usual

incision made for surgery. This allows the device to be used without any additional

incisions being made in the patients eyes. The incision may have to be made slightly

wider than normal to fit both the arms and also tools such as a phaco-emulsifier

simultaneously through the incision.

A further advantage provided by the device according to the invention is that

whilst maintaining the pupil in the dilated state, the device serves to effectively guard

the delicate edge of the iris against unintentional contact with surgical instruments.

A yet further advantage of the device of the invention is provided by arms 34

remaining partially external to the eye whilst the device is being used. This allows

easy re-positioning of the device and, more importantly, allows removal of the device

generally without introducing any surgical tools into the anterior chamber. This

greatly reduces the risk of damaging the eye during surgery. Additionally, formations

44 provide a convenient gripping point for a surgeon removing the device and also

allow the device to be sutured in the correct position whilst an operation is performed.

This can be important when surgical tools are continually being passed in and out of

the incision which may otherwise accidentally move or dislodge the device.

For reasons of convenience and sterilisation, the device will preferably be

disposable. The device can be manufactured in many sizes to cater for varying eye sizes

including, for example, animal eyes. From the above, it will be appreciated that the device according to the

invention represents significant improvements over the previously used techniques

and devices for dilating a pupil and maintaining it in a dilated state.

Although the invention has been described with reference to specific examples.

it will be appreciated by those skilled in the art that the invention may be embodied in

many other forms.

Claims

CLAIMS:-

1. A device for dilating a pupil and/or maintaining a pupil in a dilated state, said

device including a generally arcuate body having first and second ends, the outer

peripheral edge of the body having an engaging formation adapted to engage the inner

peripheral edge of an iris to retain the pupil in an expanded state, and at least one

positioning arm extending generally outwardly from one of the ends of the body so as

to remain external to the eye.

2. A device as claimed in claim 1 wherein positioning arms are provided at both

the ends of the body.

3. A device as claimed in claim 1 or claim 2 wherein the body is adapted to

deform to a generally elongated or folded configuration able to be passed through an

exterior incision in the eye and resiliently return to a substantially annular

configuration engaging the iris edge.

4. A device as claimed in claim 1 or claim 2 or claim 3 wherein the body also

includes a guide tab extending outwardly from and generally parallel to a diameter of the body for aiding insertion of the device and for supporting the body in engagement

with an edge of the iris.

5. A device as claimed in any one of the preceding claims wherein the

positioning arm or arms each terminate in a gripping formation.

6. A device as claimed in claim 5 wherein the gripping formation or formations

include a hole through which a suture thread may be passed.

7. A device as claimed in any one of the preceding claims wherein each of the

arm or arms includes a proximal portion adjacent the body and an offset distal portion extending to the gripping formation or formations so as to allow the distal portion or

portions to remain external to the eye and above the level of the iris whilst the device

is in use dilating the pupil.

8. A device as claimed in any one of the preceding claims wherein the resilience

of the body provides a radially outwardly directed force capable of urging into and

maintaining the body in a substantially annular configuration whilst engaging the iris

to expand and/or maintain the pupil in the dilated state.

9. A device as claimed in any one of the preceding claims wherein the engaging

formation is formed so as to define a continuous recessed channel between the ends.

10. A device as claimed in any one of the preceding claims wherein the body

comprises a pair of circumferentially aligned parallel axially spaced apart incomplete

rings and a series of circumferentially spaced apart curved joining members extending

from one ring to the other to define said engaging formation.

1 1. A device as claimed in any one of claims 1 to 9 wherein the body is provided

with a plurality of radially outwardly angled pairs of flaps, each pair of flaps defining

a portion of the engaging formation therebetween.

12. A device as claimed in any one of the preceding claims wherein the body is

made from a material selected from the group including prolene, poly methyl

methacrylate, nylon, silastic, silicon polyimide, polyamide or a combination thereof,

or any other material having the requisite properties of resilience and suitability for

use in surgical procedures.

13. A device as claimed in any one of the preceding claims wherein an insert of a

second material is contained within the body to give the required resilience.

14. A device as claimed in any one of the preceding claims wherein the body is

sized to provide an inner diameter the preceding in the substantially annular

configuration of between approximately 5.5mm and 7mm, the body itself has a radial

thickness of between about 0.75 and 1.25mm.

15. A device as claimed in any one of the preceding claims wherein the recess has

an axial depth of about 1.12mm.

16. A device as claimed in any one of claims 4 to 15 wherein the guide tab extends

from the outer edge of the body by about 1.25mm.

17. A device as claimed in any one of claims 7 to 16 when the distal portions of

the arms are preferably offset from the proximal portions by about 1.5 to 2.0mm in the

axial direction.

18. A device as claimed in any one of the preceding claims wherein regions of

weakness are included in the body to further facilitate resilient deformation between

the expanded annular and the elongated or folded configurations.

19. A device as claimed in any one of the preceding claims wherein the device is

tinted for increased visibility to the surgeon.

20. A device as claimed in any one of the preceding claims wherein the body, in

the annular configuration, has an included angle of between approximately 270° and

340°.