OPHTHALMIC BLADES AND INSTRUMENTS AND METHODS OF USE THEREOF

Abstract

The present invention concerns ophthalmic surgical instruments for use during ophthalmic surgery. In one form, the present invention relates to multi-purpose ophthalmic blade for making a primary incision for entry in into an anterior chamber of an eye and a side port incision. In another form, the present invention relates to an ophthalmic surgical instrument for delivery and/or removal of fluid into or from an eye. The instrument includes a hollow shaft connectable to a blade portion adapted for making a side port incision in an eye for delivery, or removal, of the fluid.

Claims

1. A multi-purpose ophthalmic blade for use, or when used, in cataract extraction surgery, said blade comprising: a shaft connectable to a handle; a first blade portion extending from the shaft along a central axis, said first blade portion comprising a pair of opposed side edge portions extending about the central axis, the side edge portions defining a first pair of opposed cutting edges each oriented at a first angle relative to said central axis and that at least partially converge towards a distal end of the first blade portion; and a second blade portion extending distally forward from the first blade portion along the central axis to a blade tip, said second blade portion comprising a pair of opposed parallel side edge portions and a pair of converging side edge portions extending distally forward from the parallel side edge portions, said converging side edge portions defining a second pair of cutting edges that converge to the blade tip, said second pair of cutting edges each being oriented at a second angle relative to said central axis, wherein said first blade portion is adapted for making a primary incision and said second blade portion is adapted for making a side port incision.

2. The blade of claim 1, wherein the first blade portion is adapted for making the primary incision having a maximum width of 2.2 mm and a length of about 4.0 mm.

3. The blade of claim 1, wherein the second blade portion is adapted for making the side portion incision having a maximum width of about 1.0 mm and a length of between about 0.7 mm and about 1.2 mm.

4. The blade of claim 1, wherein the second blade portion extends distally forward of the first blade portion a distance equal to, or less than, a multiple of 1.2 times a width of the second blade portion at its widest point.

5. The blade of claim 4, wherein the distance is equal to, or less than, a multiple of 1.1 times the width of the second blade portion at its widest point.

6. The blade of claim 4, wherein the distance is equal to, or less than, a multiple of 1.0 times the width of the second blade portion at its widest point.

7. The blade of claim 4, wherein the distance is equal to a multiple of between 0.7 and 1.0 times the width of the second blade portion at its widest point.

8. The blade of claim 1, wherein the blade includes a body defining the first blade portion and the second blade portion and wherein the body is in the form of a plate.

9. The blade of claim 8, wherein the body defines the first blade portion at or near a proximal end of the body, the second blade portion at or near the distal end of the body and a junction between the first blade portion and the second blade portion.

10. The blade of claim 9, wherein the pair of opposed side edge portions of the first blade portion flare outwards away from the central axis to define a widest part or portion of the blade and then taper towards the central axis at or near the junction as then extend between the proximal end and the junction.

11. The blade of claim 10, wherein the side edge portions gently taper in a linear direction from the widest part or portion to the junction to define distal-end facing side edge portions having the first pair of cutting edges defined thereon so as to form the primary incision when the first blade portion is advanced into the eye in a direction parallel with the central axis.

12. The blade of claim 11, wherein the distal-end facing side edge portions are oriented at the first angle relative to the central axis.

13. The blade of claim 1, wherein the first angle is between about 25° and about 35°.

14. The blade of claim 1, wherein the second angle is between about 30° and about 60°.

15. The blade of claim 1, wherein the blade includes a first marking extending laterally across an upper surface of the blade in a direction substantially perpendicular to the central axis to indicate a suitable depth of insertion for forming the primary incision and a second marking extending laterally across the upper surface of the blade in a direction substantially perpendicular to the central axis to indicate a depth of insertion for forming the side port incision.

16. The blade of claim 15, wherein the first marking is located between about 2.0 mm and 4.0 mm from the blade tip.

17. The blade of claim 15, wherein the second marking is located between about 0.7 mm and about 1.0 mm from the blade tip.

18. A method of forming a primary incision and a side port incision during cataract surgery, said method comprising: providing the multi-purpose ophthalmic blade of claim 1; forming the side port incision in an eye by at least partially advancing the blade at a first location into an anterior chamber of the eye to a junction between the first and second blade portions; and forming the primary incision in the eye by at least partially advancing the blade at a second location into the anterior chamber of the eye to an end of the opposed first cutting edges of the first blade portion.

19. The method of claim 18, wherein the first location and the second location are located about 60-90° relative to one another about the corneoscleral junction of the eye.

20. The method of claim 18, wherein the forming the side portion incision includes advancing the second blade portion into the anterior chamber of the eye a distance of between about 0.7 mm and about 1.0 mm.

21. (canceled)

Description

BRIEF DESCRIPTION OF DRAWINGS

[0150] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

[0151] FIG. 1 is an upper perspective view of a multi-purpose ophthalmic blade according to an embodiment of the present invention;

[0152] FIG. 2 is a side view of the multi-purpose ophthalmic blade as shown in FIG. 1;

[0153] FIG. 3 is an upper perspective view of a multi-purpose ophthalmic blade according to another embodiment of the present invention;

[0154] FIG. 4 is a plan view of a multi-purpose ophthalmic blade according to another embodiment of the present invention;

[0155] FIG. 5 is a plan view of a multi-purpose ophthalmic blade according to another embodiment of the present invention;

[0156] FIG. 6 is a plan view of a multi-purpose ophthalmic blade according to another embodiment of the present invention;

[0157] FIG. 7 is an upper perspective view of a surgical instrument according to an embodiment of the present invention;

[0158] FIG. 8 is another upper perspective view of the surgical instrument as shown in FIG. 7 operatively associated with a cannula;

[0159] FIG. 9 is an upper perspective view of a surgical instrument according to another embodiment of the present invention;

[0160] FIG. 10 is another upper perspective view of the surgical instrument as shown in FIG. 9 operatively associated with a cannula;

[0161] FIG. 11 is an upper perspective view of a surgical instrument according to a further embodiment of the present invention;

[0162] FIG. 12 is another upper perspective view of the surgical instrument as shown in FIG. 11 operatively associated with a cannula;

[0163] FIG. 13 is an upper perspective view of a surgical instrument according to yet another embodiment of the present invention; and

[0164] FIG. 14 is another upper perspective view of the surgical instrument as shown in FIG. 13 operatively associated with a cannula.

DETAILED DESCRIPTION

[0165] FIGS. 1 to 6 show embodiments of a multi-purpose ophthalmic blade (100) according to the present invention for use in cataract extraction surgery.

[0166] FIGS. 7 to 14 show an ophthalmic surgical instrument (300) according to differing embodiments of the present invention.

[0167] Referring to FIGS. 1 and 2, these figures show the multi-purpose ophthalmic blade (100) according to a first embodiment of the present invention. The multi-purpose ophthalmic blade (100) has a first blade portion (130) and a second blade portion (140) for respectively forming a primary incision and a side port incision during cataract extraction surgery.

[0168] The blade (100) is integrally formed from stainless steel.

[0169] The blade (100) includes a shaft (110) connectable to a handle (900; shown only in FIG. 1) and a blade body (120) defining the first blade portion (130) and the second blade portion (140).

[0170] The shaft (110) extends longitudinally in a linear direction between a pair of opposed ends, including a proximal end (112) connectable to the handle (900) and an opposed distal end (114) from which the blade body (120) and portions (130, 140) extend.

[0171] The shaft (110) is of solid construction and has a substantially circular cross-section that tapers or flattens at or near the distal end (114).

[0172] The handle (900; shown only in FIG. 1) has an elongate shape suitable for being held and manipulated by a hand of an ophthalmologist. The handle (900; shown only in FIG. 1) is formed from plastic material or materials and is overmoulded over the proximal end (112) of the shaft (110).

[0173] The shaft (110) extends a length of about 9 mm between the handle (900) and the blade body (120).

[0174] As indicated, the shaft (110) tapers or flattens at or near the distal end (114) from which the blade body (120) extends at an angle (a) of about 135° relative to the shaft (110).

[0175] Referring to FIG. 1, the blade body (120) extends from the distal end (114) of the shaft along a central axis (A) to a pointed blade tip (122). The body (120) is in the form of a plate having a substantially diamond or kite shape.

[0176] The body (120) has two opposed surfaces, including an upper surface (124) that faces outwards of an eye during surgery and an opposed lower surface (126). The opposed surfaces (124, 126) extend substantially parallel to one another and are interconnected by opposing edges, including opposed side edges, a proximal end edge from which the body (120) extends from the shaft (110), and an opposed distal end edge defining the blade tip (122) of the second blade portion (140).

[0177] The body (120) defines the first blade portion (130) at or near a proximal end of the body, the second blade portion (140) at or near the distal end of the body (120) and a junction (150) between the first and second blade portions (130, 140).

[0178] The first blade portion (130) and the second blade portion (140) extend from the shaft (110) along the central axis (A). The first blade portion (130) includes a pair of opposed side edge portions (132) that extend symmetrically about the central axis (A).

[0179] The side edge portions (132) flare gently flare outwards and away from the central axis (A) as they extend along from the proximal end at least partially towards the junction (150) to define a widest part of the blade or apex (B:B). The side edge portions (132) then gently taper at least partially towards the central axis (A) as they extend from the apex (B:B) towards the junction (150).

[0180] The apex (B:B) defines proximal end facing side edge portions (134) extending between the proximal end and the apex (B:B) and distal-end facing side edge portions (136) extending between the apex (B:B) and the junction (150).

[0181] A first pair of cutting edges (160) are defined on the distal-end facing side edge portions (136).

[0182] The proximal end facing side edge portions (134) have rounded or non-cutting edges so as not to modify the incision, i.e., enlarge the incision or cause superficial cuts, as the blade (100) is retracted.

[0183] The second blade portion (140) extends distally forward from the first blade portion (130) the central axis (A) to the blade tip (122). Like the first blade portion (130), the second blade portion (140) includes a pair of opposed side edge portions (142) that extend symmetrically about the central axis (A) and converge to the blade tip (122). The second pair of cutting edges (170) are defined on the side edge portions (142).

[0184] The first pair of cutting edges (160) extend continuously into the second pair of cutting edges (170) save that the pairs (160, 170) are oriented at different angles relative to the central axis (A).

[0185] Each pair of cutting edges (160, 170) is oriented at a blade angle relative to the central axis (A) such that they at least partially face towards the blade tip (122) to facilitate incision formation when the blade (100) is advanced into an eye in a direction parallel with the central axis (A).

[0186] The first pair of cutting edges (160) each have a blade angle (β) of about 22° relative to the central axis (A) that is greater than the blade angle (γ) of 12.5° at which the second pair of cutting edges (170) are each oriented relative to the central axis (A).

[0187] The first pair of cutting edges (160) have a maximum width extending between the opposed cutting edges, as measured at or near the apex (B:B), of about 2.4 mm.

[0188] In contrast, the second pair of opposed cutting edges (170) have a maximum width extending between the opposed cutting edges (170) as measured at or near the junction (150) of about 0.6 mm.

[0189] Referring to both FIGS. 1 and 2, in use, an ophthalmologist can form the side port incision by advancing the blade (100) up to the junction (150) into the cornea at a first location of the eye.

[0190] The ophthalmologist can then form the primary incision with the same blade (100) by advancing the blade (100) up to the apex (B:B) into the cornea at a second location of the eye in a direction substantially parallel with the central axis (A).

[0191] FIG. 3 shows the multi-purpose ophthalmic blade (100) according to a second embodiment of the present invention. For convenience, features that are similar or correspond to features of the first embodiment will again be referenced with the same reference numerals.

[0192] The multi-purpose ophthalmic blade (100) has a first blade portion (130) and a second blade portion (140) for respectively forming a primary incision and a side port incision.

[0193] The blade (100) includes a shaft (110) connectable to a handle (900) and a blade body (120) defining the first blade portion (130) and the second blade portion (140).

[0194] The shaft (110) and the handle (900) are the same as described above in respect of the first embodiment.

[0195] The blade body (120) extends from the distal end (114) of the shaft along a central axis (A) to a pointed blade tip (122). The body (120) is in the form of a plate.

[0196] The body (120) has two opposed surfaces, including an upper surface (124) that faces outwards of an eye during surgery and an opposed lower surface (126). The opposed surfaces (124, 126) extend substantially parallel to one another and are interconnected by opposing edges, including opposed side edges, a proximal end edge from which the body (120) extends from the shaft (110), and an opposed distal end edge defining the blade tip (122) of the second blade portion (140).

[0197] The body (120) defines the first blade portion (130) at or near a proximal end of the body, the second blade portion (140) at or near the distal end of the body (120) and a junction (150) between the first and second blade portions (130, 140).

[0198] The first blade portion (130) and the second blade portion (140) extend from the shaft (110) along the central axis (A). The first blade portion (130) includes a pair of opposed side edge portions (132) that extend symmetrically about the central axis (A).

[0199] The side edge portions (132) flare gently flare outwards and away from the central axis (A) as they extend along from the proximal end at least partially towards the junction (150) to define a widest part of the blade or apex (B:B). The side edge portions (132) then gently taper at least partially towards the central axis (A) as they extend from the apex (B:B) towards the junction (150).

[0200] The apex (B:B) defines proximal end facing side edge portions (134) extending between the proximal end and the apex (B:B) and distal-end facing side edge portions (136) extending between the apex (B:B) and the junction (150).

[0201] A first pair of cutting edges (160) are defined on the distal-end facing side edge portions (136).

[0202] The proximal end facing side edge portions (134) have rounded or non-cutting edges so as not to modify the incision, i.e., enlarge the incision or cause superficial cuts, as the blade (100) is retracted.

[0203] The second blade portion (140) extends distally forward from the first blade portion (130) the central axis (A) to the blade tip (122). Like the first blade portion (130), the second blade portion (140) includes a pair of opposed side edge portions (142) that extend symmetrically about the central axis (A) and converge to the blade tip (122). The second pair of cutting edges (170) are defined on the side edge portions (142).

[0204] The first pair of cutting edges (160) extend continuously into the second pair of cutting edges (170) save that the pairs (160, 170) are oriented at different angles relative to the central axis (A).

[0205] The first pair of cutting edges (160) each have a blade angle (β) of about 22° relative to the central axis (A) that is greater than the blade angle (γ) of 12.5° at which a distal portion of the second pair of cutting edges (170) are each oriented relative to the central axis (A) and converge to the blade tip (122).

[0206] The first pair of cutting edges (160) have a maximum width extending between the opposed cutting edges, as measured at or near the apex (B:B), of about 2.4 mm.

[0207] In contrast, the second pair of opposed cutting edges (170) have a maximum width extending between the opposed cutting edges (170) as measured at or near the junction (150) of about 0.6 mm.

[0208] Further, the second pair of opposed cutting edges (170) includes the distal portion that converges to the blade tip (122) and a proximal portion in which the opposed cutting edges (170) extend substantially parallel to one another from the distal portion to the junction (150).

[0209] FIG. 4 shows the multi-purpose ophthalmic blade (100) according to a third embodiment of the present invention. For convenience, features that are similar or correspond to features of the first embodiment will again be referenced with the same reference numerals.

[0210] The multi-purpose ophthalmic blade (100) has a first blade portion (130) and a second blade portion (140) for respectively forming a primary incision and a side port incision during cataract extraction surgery.

[0211] The first blade portion (130) includes a pair of opposed side edge portions (132) that extend symmetrically about central axis (A).

[0212] The side edge portions (132) flare gently flare outwards and away from the central axis (A) as they extend along from the proximal end at least partially towards the junction (150) to define a widest part of the blade or apex (B:B). The side edge portions (132) then gently taper at least partially towards the central axis (A) as they extend from the apex (B:B) towards the junction (150).

[0213] The apex (B:B) defines proximal end facing side edge portions (134) extending between the proximal end and the apex (B:B) and distal-end facing side edge portions (136) extending between the apex (B:B) and the junction (150).

[0214] A first pair of cutting edges (160) are defined on the distal-end facing side edge portions (136).

[0215] The proximal end facing side edge portions (134) have rounded or non-cutting edges so as not to modify the incision, i.e., enlarge the incision or cause superficial cuts, as the blade (100) is retracted.

[0216] The second blade portion (140) extends distally forward from the first blade portion (130) along the central axis (A) to the blade tip (122). The second blade portion (140) includes a pair of opposed parallel side edge portions (141) and a pair of converging side edge portions (142) extending distally forward from the parallel side edge portions (141). The converging side edge portions (142) converge to the blade tip (122). The second pair of cutting edges (170) are defined on the converging side edge portions (142).

[0217] The first pair of cutting edges (160) and the second pair of cutting edges (170) are oriented at different angles relative to the central axis (A).

[0218] The first pair of cutting edges (160) each have a blade angle (β) of about 33° relative to the central axis (A). The second pair of cutting edges (170) each have a blade angle (γ) of about 60° relative to the central axis (A).

[0219] The first pair of cutting edges (160) have a maximum width extending between the opposed cutting edges, as measured at or near the apex (B:B), of about 2.2 mm.

[0220] In contrast, the second pair of opposed cutting edges (170) have a maximum width extending between the opposed cutting edges (170) as measured at or near the junction (150) or between opposed parallel side edge portions (141) of about 1.0 mm.

[0221] The second blade portion (140) has a length, as measured between the blade tip (122) and the junction (150) of about 1.0 mm or a multiple of 1.0 times the maximum width of the second blade portion (140).

[0222] FIG. 5 shows the multi-purpose ophthalmic blade (100) according to a fourth embodiment of the present invention. For convenience, features that are similar or correspond to features of the first embodiment will again be referenced with the same reference numerals.

[0223] The blade (100) according to the fourth embodiment is substantially the same as the blade (100) shown in the third embodiment save that the second blade portion (140) has a blade angle (γ) of about 42° relative to the central axis (A).

[0224] FIG. 6 shows the multi-purpose ophthalmic blade (100) according to a fifth embodiment of the present invention. For convenience, features that are similar or correspond to features of the first embodiment will again be referenced with the same reference numerals.

[0225] The blade (100) according to the fifth embodiment is substantially the same as the blades (100) shown in the third and fourth embodiments save that the second blade portion (140) has a blade angle (γ) of about 33° relative to the central axis (A).

[0226] FIG. 7 shows a surgical instrument (300) according to a first embodiment of the present invention for delivery and removal of viscoelastic fluid into or from an eye in a direction substantially parallel with the central axis (A).

[0227] The instrument (300) includes a hollow shaft (310) connectable to a syringe or cannula in fluid communication with a source of the viscoelastic fluid and a blade portion (320) adapted for making a sclerocorneal tunnel or side portion incision in the eye for the delivery or removal of the viscoelastic fluid.

[0228] The shaft (310) and the blade portion (320) of the instrument (300) are integrally formed from stainless steel.

[0229] The hollow shaft (310) is sized and shaped for connecting the blade portion (320) to the source of viscoelastic fluid and providing a conduit therebetween.

[0230] The shaft (310) includes a pair of opposed ends and extends longitudinally therebetween. The opposed ends include a proximal end (312) connectable to the source or cannula and an opposed distal end (314) from which the blade portion (320) extends. The opposed ends (312, 314) are open ends to enable the viscoelastic fluid to be delivered and removed from an eye via the distal end (314).

[0231] The shaft (310) is of tubular construction and has a substantially circular cross-section.

[0232] The shaft (310) has a length of between about 6 mm and about 12 mm and a diameter of about 0.6-0.8 mm.

[0233] As indicated, the blade portion (320) extends from the shaft (310) along a central axis (A) to a blade tip (322) and includes a pair of asymmetrical side edge portions (324) with a cutting edge (360) at least partially defined on one side edge portion (324A).

[0234] The cutting edge (360) is oriented at a blade angle (a) of about 12.5° relative to the central axis (A) and extends to the blade tip (322) such that the cutting edge (360) at least partially faces towards the blade tip (322) to facilitate incision formation when the blade portion (320) is advanced into the eye in a direction parallel with the central axis (A).

[0235] The blade portion (320) is in the form of a plate having a substantially triangular, diamond or kite profile shape.

[0236] The blade portion (320) has two opposed surfaces, including an inner surface (324) and an opposed outer surface (326). The opposed surfaces (324, 326) extend substantially parallel to one another are interconnected by opposing edges, including opposed side edges, a proximal end edge from which the blade portion (320) extends from the distal end (314) of the shaft (310) and an opposed distal end edge defining the blade tip (322).

[0237] In the embodiment shown, the side edge portion (324A) upon which the cutting edge (360) is defined flares out at or near the proximal end to define a proximal-end facing side edge portion (332), a widest part or apex (B:B) of the blade portion (320) and a distal-end facing side edge portion (334) that gently tapers toward the blade tip (322) in a linear direction. The cutting edge (360) is defined on the distal-end facing side edge portion (334).

[0238] The distal end (314) of the shaft (310) and the proximal-end facing side edge portion partially overlap. Advantageously, this enables the distal end (314) of the shaft (310) to be readily inserted into the incision as the blade portion (320) is advanced into the eye in a direction parallel with the central axis (A).

[0239] The blade portion (320) may have a maximum width, as measured at the apex (B:B), of about 0.8 mm.

[0240] The proximal-end facing side edge portion (332) has a rounded or non-cutting edge so as not to modify an incision, i.e., enlarge the incision or cause superficial cuts, as the blade portion (320) is retracted.

[0241] In the embodiment shown, the proximal end (312) of the shaft (310) may be connectable to a cannula by way of a friction fit.

[0242] Referring to FIG. 8, in this embodiment the instrument (300) shown in FIG. 7 is shown in the form of a cannula (410) having a male Luer-Lok™ connection fitting (800) for connecting to a syringe containing the viscoelastic fluid, for example.

[0243] The male Luer-Lok™ connection fitting (800) is overmoulded over the proximal end (312) of the shaft (310). Further, the shaft (310) including distal portion angled relative to a proximal portion at an angle of about 135°.

[0244] FIG. 9 shows a surgical instrument (300) according to a second embodiment of the present invention for delivery and removal of viscoelastic fluid into or from an eye. For convenience, features that are similar or correspond to features of the first embodiment will again be referenced with the same reference numerals.

[0245] In this embodiment, the surgical instrument (300) includes a shaft (310) as previously described.

[0246] However, in contrast to the first embodiment, the blade portion (320), which extends from the shaft (310) along a central axis (A) to a blade tip (322), includes a pair of symmetrical side edge portions (324) with cutting edges (360) at least partially defined on both side edge portions (324).

[0247] In this embodiment, both side edge portions (324) flare out at or near the proximal end to define proximal-end facing side edge portions (332), a widest part or apex (B:B) of the blade portion (320) and distal-end facing side edge portions (334) that gently tapers toward the blade tip (322) in a linear direction. The cutting edges (360) is defined on the distal-end facing side edge portions (334).

[0248] The cutting edges (360) are each oriented at a blade angle (a) of about 12.5° relative to the central axis (A) and extend to the blade tip (322) such that the cutting edges (360) at least partially faces towards the blade tip (322) to facilitate incision formation when the blade portion (320) is advanced into the eye in a direction parallel with the central axis (A).

[0249] The blade portion (320) has a maximum width, as measured at the apex (B:B), of about 0.8 mm.

[0250] The proximal-end facing side edge portions (332) each have a rounded or non-cutting edge so as not to modify an incision, i.e., enlarge the incision or cause superficial cuts, as the blade portion (320) is retracted.

[0251] In the embodiment shown, the proximal end (312) of the shaft (310) is connectable to a cannula by way of a friction fit.

[0252] Referring to FIG. 7, in this embodiment the instrument (300) shown in FIG. 6 is shown in the form of a cannula (610) having a male Luer-Lok™ connection fitting (800) for connecting to a syringe containing the viscoelastic fluid, for example.

[0253] The male Luer-Lok™ connection fitting (800) is overmoulded over the proximal end (312) of the shaft (310). Further, the shaft (310) including distal portion angled relative to a proximal portion at an angle of about 135°.

[0254] FIG. 11 shows a surgical instrument (300) according to a third embodiment of the present invention for delivery and removal of viscoelastic fluid into or from an eye. For convenience, features that are similar or correspond to features of the first or second embodiments will again be referenced with the same reference numerals.

[0255] In this embodiment, the surgical instrument (300) includes a shaft (310) as previously described.

[0256] The blade portion (320) extends from the shaft (310) along a central axis (A) to a blade tip (322), and includes a pair of symmetrical side edge portions (324) with cutting edges (360) defined on both side edge portions (324).

[0257] The cutting edges (360) are each oriented at a blade angle (a) of about 12.5° relative to the central axis (A) and extend to the blade tip (322) such that the cutting edges (360) at least partially faces towards the blade tip (322) to facilitate incision formation when the blade portion (320) is advanced into the eye in a direction parallel with the central axis (A).

[0258] In contrast to the first and second embodiments, the proximal end of the blade portion (320) extends at least partially about a circumference of the distal end (312) of the shaft (310). Advantageously, this enables the distal end (312) of the shaft (310) to be readily inserted into the incision as the blade portion (320) is advanced into the eye in a direction parallel with the central axis (A).

[0259] Further, in this embodiment, both side edge portions (324) gently taper or converge toward the blade tip (322) in a linear direction from the proximal end. Accordingly, the proximal end is the widest part or apex (B:B) of the blade portion (320) and has a maximum width of about 0.6 mm.

[0260] In the embodiment shown, the proximal end (312) of the shaft (310) is connectable to a cannula by way of a friction fit.

[0261] Referring to FIG. 12, in this embodiment the instrument (300) shown in FIG. 11 is shown in the form of a cannula (810) having a male Luer-Lok™ connection fitting (800) for connecting to a syringe containing the viscoelastic fluid, for example.

[0262] The male Luer-Lok™ connection fitting (800) is overmoulded over the proximal end (312) of the shaft (310). Further, the shaft (310) including distal portion angled relative to a proximal portion at an angle of about 135°.

[0263] FIG. 13 shows a surgical instrument (300) according to a fourth embodiment of the present invention for delivery and removal of viscoelastic fluid into or from an eye. For convenience, features that are similar or correspond to features of the first or second embodiments will again be referenced with the same reference numerals.

[0264] In this embodiment, the surgical instrument (300) includes a shaft (310) as previously described.

[0265] The blade portion (320) extends from the shaft (310) along a central axis (A) to a blade tip (322), and includes a pair of symmetrical side edge portions (324) with a cutting edge (360) defined on one side edge portion (324A).

[0266] The cutting edge (360) is oriented at a blade angle (a) of about 12.5° relative to the central axis (A) and extends to the blade tip (322) such that the cutting edge (360) at least partially faces towards the blade tip (322) to facilitate incision formation when the blade portion (320) is advanced into the eye in a direction parallel with the central axis (A).

[0267] Like with the third embodiment, the proximal end of the blade portion (320) extends at least partially about a circumference of the distal end (312) of the shaft (310). Advantageously, this enables the distal end (312) of the shaft (310) to be readily inserted into the incision as the blade portion (320) is advanced into the eye in a direction parallel with the central axis (A).

[0268] Further, in this embodiment, both side edge portions (324) gently taper or converge toward the blade tip (322) in a linear direction from the proximal end. Accordingly, the proximal end is the widest part or apex (B:B) of the blade portion (320) and has a maximum width of about 0.6 mm.

[0269] In the embodiment shown, the proximal end (312) of the shaft (310) is connectable to a cannula by way of a friction fit.

[0270] Referring to FIG. 14, in this embodiment the instrument (300) shown in FIG. 13 is shown in the form of a cannula (1010) having a male Luer-Lok™ connection fitting (800) for connecting to a syringe containing the viscoelastic fluid, for example.

[0271] The male Luer-Lok™ connection fitting (800) is overmoulded over the proximal end (312) of the shaft (310). Further, the shaft (310) including distal portion angled relative to a proximal portion at an angle of about 135°.

[0272] In the present specification and claims (if any), the word ‘comprising’ and its derivatives including ‘comprises’ and ‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers.

[0273] Reference throughout this specification to ‘one embodiment’ or ‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[0274] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.