Patent Description:
To date, an eyeball attachment tube (also referred to as trocar, cannula) that is temporarily attached to an outer membrane of an eyeball in ophthalmic surgery for communication between the inside and the outside of the eyeball has been known (for example, see <CIT>, <CIT>). This type of eyeball attachment tube has a large diameter portion in which an outer diameter is increased on the proximal end side. When the eyeball attachment tube is attached to an eyeball, the large diameter portion comes into contact with the external surface of the eyeball to act as a stopper, thereby preventing the entirety of the eyeball attachment tube from being inserted into the eyeball.

As described in <CIT>, in a case where the eyeball attachment tube is attached for communication with an anterior chamber, the eyeball attachment tube needs to be attached at a border (also referred to as corneosclera or corneal limbus) between a cornea and a sclera, or at a peripheral portion of the cornea. This is because, if the eyeball attachment tube is attached near the center of a cornea, the cornea may be deformed. In a case where the eyeball attachment tube is attached at the border or the peripheral portion, if the eyeball attachment tube punctures the external surface of the border or the peripheral portion so as to be perpendicular thereto, an iris or a crystalline lens may be injured. In order to prevent this, when the anteroposterior direction is defined such that the corneal apex side is the anterior side and the retina center side is the posterior side, the eyeball attachment tube needs to be attached so as to be oriented in the horizontal direction crossing the anteroposterior direction (more specifically, slightly oriented diagonally forward). The peripheral portion of the cornea represents a portion of the cornea which is slightly closer to the cornea center side than the border is. The "peripheral portion of a cornea" may be defined as including the border or the "border between a cornea and a sclera" may be defined as including the peripheral portion.

However, in a case where the eyeball attachment tube is attached so as to deviate relative to the direction perpendicular to the external surface of the eyeball, for example, in a case where the eyeball attachment tube is attached in the horizontal direction at the border or the peripheral portion, a gap may be generated between the large diameter portion of the eyeball attachment tube and the external surface of the eyeball, and the eyeball attachment tube becomes unstable and may be removed from the eyeball.

<CIT> discloses an eyeball attachment tube that is temporarily attached to an outer membrane of an eyeball.

This disclosure has been made in view of the aforementioned problem, and an object of this disclosure is to inhibit an eyeball attachment tube from becoming unstable in a case where the eyeball attachment tube is attached so as to deviate relative to the direction perpendicular to an external surface of an eyeball.

An eyeball attachment tube of this disclosure is directed to an eyeball attachment tube that is temporarily attached to an outer membrane of an eyeball in ophthalmic surgery for communication between an inside and an outside of the eyeball.

An end portion, in a parallel direction to a center axis of the tubular portion, of the large diameter portion on the tubular portion side is shaped so as to have a height difference in the parallel direction between one end and another end in a direction perpendicular to the center axis in a side view.

An entirety of the end portion is formed as an inclined plane relative to the center axis.

An end portion, of the large diameter portion, on an opposite side to the end portion on the tubular portion side in the parallel direction is formed as a plane perpendicular to the center axis.

In this configuration, in a side view, the end portion of the large diameter portion is shaped so as to have a height difference, in the direction parallel to the center axis, between one end and the other end in the direction perpendicular to the center axis of the tubular portion. Therefore, in a case where the eyeball attachment tube is attached in a direction deviating relative to the direction perpendicular to the external surface of the eyeball, a gap between the external surface of the eyeball and the large diameter portion can be reduced by the height difference. Thus, the eyeball attachment tube can be inhibited from becoming unstable. The entirety of the end portion of the large diameter portion on the tubular portion side is formed as the plane inclined relative to the center axis. Therefore, as compared with a case where a part of the end portion of the large diameter portion is formed as an inclined plane, the eyeball attachment tube can be further inhibited from becoming unstable when attached to the external surface of the eyeball. Specifically, the large diameter portion can be inhibited from rolling on an eyeball, and the eyeball attachment tube attached to the eyeball can be inhibited from becoming unstable in the clockwise or counterclockwise direction around a connection portion between the large diameter portion and the tubular portion in a side view. Furthermore, the end portion of the large diameter portion on the side opposite to the inclined surface side is formed as the plane perpendicular to the center axis. Therefore, the eyeball attachment tube can be attached to the external surface of an eyeball by using a conventional instrument described in Patent Documents (for example, <CIT>, <CIT>). In other words, an instrument for attachment can be shared between an instrument for attaching the eyeball attachment tube of this disclosure to an eyeball and an instrument for attaching a conventional eyeball attachment tube to an eyeball.

An embodiment of this disclosure will be described below with reference to the drawings. An eyeball attachment tube <NUM> (cannula, trocar) (hereinafter, may be simply referred to as attachment tube) shown in <FIG> is temporarily attached to a corneosclera of an eyeball in ophthalmic surgery such as cataract surgery and glaucoma surgery, for communication between an anterior chamber and the outside of the eyeball. The attachment tube <NUM> includes a tubular portion <NUM> formed in a linear tubular shape, and a large diameter portion <NUM> that is disposed on the proximal end side of the tubular portion <NUM> and that has an outer diameter larger than an outer diameter of the tubular portion <NUM>.

A center axis L1 of the tubular portion <NUM> linearly extends. The tubular portion <NUM> is formed in such a shape (that is, cylindrical shape) as to have a circular outer circumferential line and a circular inner circumferential line as viewed in a plane (direction in <FIG>) to which the center axis L1 is orthogonal. However, the tubular portion <NUM> may be formed in a tubular shape that has an outer circumferential line and an inner circumferential line having other shapes. The tubular portion <NUM> has a through hole <NUM> formed therein so as to penetrate from one end to the other end in the direction in which the center axis L1 extends (see <FIG>, <FIG>). A length d (see <FIG>) of a portion of the tubular portion <NUM> which is exposed from the large diameter portion <NUM> is set to be greater than the thickness of a corneosclera and set such that a leading end <NUM> of the tubular portion <NUM> does not protrude from an anterior chamber in a state where the corneosclera is punctured by the tubular portion <NUM>. Specifically, the length d is set to be, for example, larger than or equal to <NUM> and less than or equal to <NUM>. From the viewpoint of preventing deformation of an eyeball when a corneosclera is punctured by the tubular portion <NUM> or the viewpoint of naturally closing a hole formed in the corneosclera when the tubular portion <NUM> is removed from the corneosclera, the outer diameter of the tubular portion <NUM> is preferably small, and can be, for example, less than or equal to <NUM>.

The large diameter portion <NUM> is formed in a tubular shape having an outer diameter larger than the outer diameter of the tubular portion <NUM>. In this embodiment, the large diameter portion <NUM> is formed in such a shape (that is, cylindrical shape) as to have a circular outer circumferential line that is concentric with the outer circumferential line of the tubular portion <NUM> as viewed in a plane (direction in <FIG>) to which the center axis L1 of the tubular portion <NUM> is orthogonal. However, the large diameter portion <NUM> may be formed in a tubular shape having another shape. The large diameter portion <NUM> is connected to the proximal end side portion of the tubular portion <NUM> in a state where, for example, a part of the proximal end side portion of the tubular portion <NUM> is fitted into the large diameter portion <NUM>. The center axis of the large diameter portion <NUM> is coaxial with the center axis L1 of the tubular portion <NUM>. Inside the large diameter portion <NUM>, a channel <NUM> communicating with the channel <NUM> inside a portion of the tubular portion <NUM> which is exposed from the large diameter portion <NUM> is formed (see <FIG>). The channel <NUM> is formed to be coaxial with the channel <NUM> of the tubular portion <NUM>. The channel <NUM> may be formed by a channel in a portion of the tubular portion <NUM> which is fitted into the large diameter portion <NUM> or formed of a material other than a material of the tubular portion <NUM>.

The large diameter portion <NUM> is formed in, for example, a shape obtained by diagonally cutting one end side portion, in the axial direction, of a cylindrical member. Specifically, the entirety of an end portion <NUM> of the large diameter portion <NUM> on the leading end <NUM> side (the portion of the tubular portion <NUM> which is exposed from the large diameter portion <NUM>) of the tubular portion <NUM> in the axis L1 direction is formed as a plane diagonal relative to the center axis L1. In other words, the entirety of the end portion <NUM> is angled relative to an imaginary plane <NUM> (see <FIG>) perpendicular to the center axis L1. In still other words, the end portion <NUM> is formed in a shape having, in the direction parallel to the center axis L1, a height difference x between one end 31b side and the other end 31a side in the direction perpendicular to the center axis L1 in the side view in <FIG>. Specifically, the end portion <NUM> is shaped so as to be gradually displaced to (approach) the leading end <NUM> of the tubular portion <NUM> from the one end 31b side toward the other end 31a side.

More specifically, in the side view in <FIG>, the end portion <NUM> is formed so as to render an outline (straight line) diagonal relative to the center axis L1. The end portion <NUM> has a portion 31a (referred to as portion closest to the leading end) closest to the leading end <NUM> and a portion 31b (referred to as portion closest to the proximal end) closest to the proximal end <NUM> of the large diameter portion <NUM> (see <FIG>). The portions 31a, 31b are disposed on <NUM>° opposite sides in a circle having, as the center of the circle, the center O (point on the center axis L1) of the tubular portion <NUM> as viewed in the direction in <FIG>. The end portion <NUM> is formed so as to be gradually displaced toward the proximal end <NUM> as the end portion <NUM> approaches the portion 31b closest to the proximal end from the portion 31a closest to the leading end along the radial direction D (see <FIG>) in the circle having, as the center of the circle, the center O of the tubular portion <NUM>. The end portion <NUM> is formed so as to be gradually displaced toward the proximal end <NUM> as the end portion <NUM> approaches the portion 31b closest to proximal end from the portion 31a closest to the leading end along the circumferential direction E (see <FIG>) in the circle.

The cross-section in <FIG> represents a cross-section obtained by cutting the attachment tube <NUM> at a plane (plane represented by a line VI-VI in <FIG>) including therein the center axis L1, the portion 31a closest to the leading end, and the portion 31b closest to the proximal end. <FIG> illustrates a cross-section obtained by cutting the attachment tube <NUM> at a plane (plane represented by a line VII-VII in <FIG>) perpendicular to the cross-section in <FIG>. In <FIG>, a cross-sectional line 31c of the end portion <NUM> is perpendicular to the center axis L1. A cross-sectional line of the end portion <NUM> formed by cutting the attachment tube <NUM> at any plane including the center axis L1 therein is rendered as a straight line diagonal relative to the center axis L1 except for the cross-sectional line 31c in <FIG>.

As shown in <FIG>, an angle θ forming an acute angle in angles between the center axis L1 and a straight line L2 passing through the portion 31a closest to the leading end and the portion 31b closest to the proximal end is defined as an inclination angle of the end portion <NUM> relative to the center axis L1. The inclination angle θ is greater than <NUM>° and less than <NUM>°. Specifically, the inclination angle θ is set as an angle corresponding to inclination of the external surface of the corneosclera, and is set to be, for example, greater than or equal to <NUM>° and less than or equal to <NUM>°. More specifically, when the anteroposterior direction is defined such that the corneal apex side in an anterior segment is the anterior side, and the retina center side is the posterior side, and the direction perpendicular to the anteroposterior direction is defined as the horizontal direction, the inclination angle of the corneosclera relative to the horizontal direction is, for example, <NUM> to <NUM>°. In a case where the attachment tube <NUM> is attached in the horizontal direction, the inclination angle θ is set as an angle (<NUM> to <NUM>°) that is approximately equal to the inclination angle of the corneosclera. For example, in a case where the attachment tube <NUM> is attached so as to be oriented forward by about <NUM>° relative to the horizontal direction, the inclination angle θ is set as an angle (<NUM> to <NUM>°) obtained by subtracting the forward inclining angle (<NUM>°) from the inclination angle (<NUM> to <NUM>°) of the corneosclera. The end portion <NUM> functions as a portion that is in contact with the external surface of the outer membrane when the attachment tube <NUM> is attached to the outer membrane of the eyeball.

The proximal end <NUM>, of the large diameter portion <NUM>, which is an end portion on the side opposite to the end portion <NUM> side in the direction parallel to the axis L1 is formed as a plane perpendicular to the center axis L1. In the proximal end <NUM>, an opening <NUM> for the channel <NUM> of the large diameter portion <NUM> is formed.

The large diameter portion <NUM> has a valve <NUM> for inhibiting liquid from flowing out from the opening <NUM> through the channels <NUM>, <NUM>. The valve <NUM> is disposed at a position of the opening <NUM> of the channel <NUM> or disposed in front of the opening <NUM>. For example, a member having a slit formed in an elastic material such as rubber is disposed as the valve <NUM> so as to close the channel <NUM> in the large diameter portion <NUM>. The slit is elastically deformed when a surgical instrument or the like is inserted into the attachment tube <NUM>, whereby the valve <NUM> opens. The slit is restored to an original state when the instrument is removed from the attachment tube <NUM>, whereby the valve <NUM> is closed.

The attachment tube <NUM> is attached to a border <NUM> (corneosclera) between a cornea <NUM> and a sclera <NUM> of an eyeball of a subject to be operated in ophthalmic surgery, as shown in <FIG>. As an instrument <NUM> for attaching the attachment tube <NUM> to the corneosclera <NUM>, the instrument similar to that disclosed in <CIT> or <CIT> is used. The instrument <NUM> includes a bar-like handle portion <NUM>, and a needle portion <NUM> connected to a leading end 41a of the handle portion <NUM>. The leading end 41a is formed as a plane perpendicular to an axis L3 of the handle portion <NUM> and the needle portion <NUM>.

In a procedure for attaching the attachment tube <NUM> to the corneosclera <NUM>, firstly, the needle portion <NUM> is caused to pass through the hole <NUM> in the attachment tube <NUM> to attach the attachment tube <NUM> to the instrument <NUM>. At this time, the proximal end <NUM> of the large diameter portion <NUM> of the attachment tube <NUM> is brought into contact with the leading end 41a of the handle portion <NUM>, whereby a part of the needle portion <NUM> from the leading end protrudes from the attachment tube <NUM> while the attachment tube <NUM> is held at the leading end 41a and the needle portion <NUM>. In <FIG>, for facilitating understanding of the structure of the instrument <NUM>, a gap between the leading end 41a of the handle portion <NUM> and the proximal end <NUM> of the large diameter portion <NUM> is shown. However, the leading end 41a and the proximal end <NUM> are actually in contact with each other.

Thereafter, a person (doctor) who performs the surgery holds the handle portion <NUM> and punctures the corneosclera <NUM> with the needle portion <NUM>. At this time, the needle portion <NUM> is oriented almost in the horizontal direction (specifically, oriented slightly forward (toward cornea apex side) relative to the horizontal direction) in order to prevent the needle portion <NUM> from injuring an iris <NUM> or a crystalline lens <NUM>.

The person who performs the surgery inserts the tubular portion <NUM> of the attachment tube <NUM> into the corneosclera <NUM> while puncturing the corneosclera <NUM> with the needle portion <NUM> to form a hole in the corneosclera <NUM>. At this time, while the tubular portion <NUM> is positioned forward of the iris <NUM>, the tubular portion <NUM> is inserted until the large diameter portion <NUM> comes into contact with an external surface 103a of the corneosclera <NUM>. The portion 31a, closest to the leading end, of the large diameter portion <NUM> is brought into contact with the external surface 103a on the cornea <NUM> side (anterior side), and the portion 31b closest to the proximal end is brought into contact with the external surface 103a on the sclera <NUM> side (posterior side). The person who performs the surgery may adjust the orientation of the attachment tube <NUM> around the axis L1 by rotating the instrument <NUM> around the axis of the needle portion <NUM>.

Thereafter, the instrument <NUM> (the needle portion <NUM>) is retracted (pulled) from the corneosclera <NUM>, whereby only the attachment tube <NUM> is indwelt in the corneosclera <NUM> (see <FIG>). When the instrument <NUM> is retracted, the large diameter portion <NUM> of the attachment tube <NUM> may be held by tweezers or the like in order to prevent removal of the attachment tube <NUM> from the corneosclera <NUM>.

As shown in <FIG>, in a state where the attachment tube <NUM> is attached to the corneosclera <NUM>, the tubular portion <NUM> is in a state of puncturing the corneosclera <NUM>, and the large diameter portion <NUM> is in a state of being exposed externally from the corneosclera <NUM>. Furthermore, the end portion <NUM> of the large diameter portion <NUM> is in contact with the external surface 103a of the corneosclera <NUM>. Moreover, the leading end <NUM> of the tubular portion <NUM> is positioned in an anterior chamber interior <NUM> (see <FIG>). The anterior chamber interior <NUM> is a region between the cornea <NUM> and the crystalline lens <NUM>, and is a region forward of the iris <NUM>.

During the succeeding surgery, a surgical instrument (for example, instrument for resecting a tissue in the eye) is inserted through the attachment tube <NUM> into the anterior chamber interior <NUM>, or liquid (water) is injected through the attachment tube <NUM> into the anterior chamber interior <NUM> such that a pressure (intraocular pressure) of the anterior chamber interior <NUM> is maintained constant. As glaucoma surgery, for example, trabeculectomy is performed so as to improve flow of aqueous humor and lower an abnormally high intraocular pressure. In this case, for example, an instrument (cutting tool) for the trabeculectomy is inserted through the attachment tube <NUM> into the anterior chamber interior <NUM>.

When the surgery ends, the large diameter portion <NUM> of the attachment tube <NUM> is held by tweezers or the like and pulled, whereby the attachment tube <NUM> is removed from the eyeball. Thereafter, suture is performed for closing the hole formed in the corneosclera <NUM> as necessary.

Thus, in this embodiment, the end portion <NUM> of the large diameter portion <NUM> on the tubular portion <NUM> side is formed as a plane inclined relative to the center axis L1 of the tubular portion <NUM>. Therefore, in a case where the attachment tube <NUM> is attached to the corneosclera <NUM> almost in the horizontal direction, the entirety of the end portion <NUM> can be brought into contact with the external surface 103a of the corneosclera <NUM>. Thus, for example, when a surgical instrument having been inserted in the anterior chamber interior <NUM> through the attachment tube <NUM> is moved, the attachment tube <NUM> can be inhibited from becoming unstable, and the attachment tube <NUM> can be inhibited from being removed from the corneosclera <NUM>.

The proximal end <NUM> of the large diameter portion <NUM> is formed as a plane perpendicular to the center axis L1. Therefore, when the attachment tube <NUM> is attached by using the instrument <NUM> (see <FIG>), an area in which the leading end 41a of the handle portion <NUM> and the proximal end <NUM> of the large diameter portion <NUM> are in contact with each other can be increased, and attachment of the attachment tube <NUM> with use of the instrument <NUM> is facilitated.

Meanwhile, in a conventional attachment tube <NUM> shown in <FIG>, an end portion <NUM> of a large diameter portion <NUM> is formed so as to be perpendicular to a center axis L6 of a tubular portion <NUM>. Therefore, when the attachment tube <NUM> is attached to the corneosclera <NUM>, a gap a is formed between the external surface of the corneosclera <NUM> and the large diameter portion <NUM>, and the attachment tube <NUM> becomes unstable and is likely to be removed from the corneosclera <NUM>. In <FIG>, the outline of the external surface of the corneosclera <NUM> is indicated by dotted lines.

This disclosure is not limited to the above-described embodiment, and various modifications can be made. In this embodiment, an example in which the end portion of the large diameter portion is an inclined plane is described. However, the end portion of the large diameter portion may not necessarily be formed as an inclined plane when a height difference is formed, in the direction parallel to the center axis, between one of the end portions of the large diameter portion and the other thereof in the direction perpendicular to the center axis in a side view. <FIG> shows an example in which the end portion of the large diameter portion is formed in a shape other than the inclined plane. An end portion <NUM> of a large diameter portion <NUM> of an attachment tube <NUM> shown in <FIG> is formed in a shape displaced toward the leading end of a tubular portion <NUM> in a step-like manner (in other words, stepwise) as the end portion <NUM> approaches the other end 71c from one end 71a in the direction perpendicular to the center axis L4 of the tubular portion <NUM>. Specifically, a portion 71b of the end portion <NUM> on the one end 71a side in the direction perpendicular to the center axis L4 of the tubular portion <NUM> is formed as a plane perpendicular to the center axis L4. A portion 71d of the end portion <NUM> on the other end 71c side in the direction perpendicular to the center axis L4 is formed as a plane perpendicular to the center axis L4. A stepped portion 71e is formed between the portions 71b and 71d so as to be parallel to the center axis L4. For example, a position of the stepped portion 71e may overlap the center axis L4 in the side view in <FIG>. The stepped portion 71e is set to have a size corresponding to the inclination of the external surface of the corneosclera <NUM>. Specifically, the size of the stepped portion 71e is set such that, when the attachment tube <NUM> is attached to the corneosclera <NUM>, at least a part of the portion 71d of the end portion <NUM>, which is close to the leading end of the tubular portion <NUM>, is in contact with the external surface of the corneosclera <NUM> on the cornea side, and at least a part of the portion 71b of the end portion <NUM>, which is close to the proximal end of the large diameter portion <NUM>, is in contact with the external surface of the corneosclera <NUM> on the sclera side.

Also in such a structure, when the attachment tube <NUM> is attached to the corneosclera <NUM>, the portion 71d on the leading end side is brought into contact with the corneosclera <NUM> on the cornea side, and the portion 71b on the proximal end side is brought into contact with the corneosclera <NUM> on the sclera side, whereby a gap between the large diameter portion <NUM> and the corneosclera <NUM> can be reduced as compared with a conventional structure in <FIG>. In <FIG>, the outline of the external surface of the corneosclera <NUM> is indicated by a dotted line.

In the above-described embodiment (example shown in <FIG>), an example in which the end portion of the large diameter portion is a plane inclined relative to the center axis, is described. However, as shown in <FIG>, the end portion of the large diameter portion may be formed as a recessed curved surface that is inclined relative to the center axis. An end portion <NUM> of a large diameter portion <NUM> of an attachment tube <NUM> shown in <FIG> is formed as a recessed curved surface that is inclined relative to a center axis L5 of a tubular portion <NUM>. Specifically, as viewed on the cross-section in <FIG>, the end portion <NUM> is gradually displaced toward the leading end of the tubular portion <NUM> as the end portion <NUM> approaches the other end 11a from one end 11b in the direction perpendicular to the center axis L5, and is formed so as to render a curved line diagonal relative to the center axis L5. <FIG> shows a first cross-section obtained by cutting the attachment tube <NUM> at the same position as the position of the line VI-VI in <FIG>.

<FIG> shows a second cross-section obtained by cutting the attachment tube <NUM> at the same position as the position of the line VII-VII in <FIG>. In other words, <FIG> shows a second cross-section obtained by cutting the attachment tube <NUM> at the plane, perpendicular to the sheet surface in <FIG>, including the center axis L5 therein. Also on the cross-section shown in <FIG>, a cross-sectional line 11c rendered by the end portion <NUM> is a curved line. Specifically, the cross-sectional line 11c is gradually displaced toward a proximal end <NUM> of the large diameter portion <NUM> so as to form a curved line shape as the cross-sectional line 11c approaches the center axis L5 from one end portion 11d of the cross-sectional line 11c, and gradually displaced toward the leading end of the tubular portion <NUM> so as to form a curved line shape as the cross-sectional line 11c approaches the other end portion 11e of the cross-sectional line 11c from the center axis L5. Both of the end portions 11d and 11e of the cross-sectional line 11c are disposed at the same positions (the same axial positions) in the direction in which the center axis L5 extends.

A curvature of the curved surface formed by the end portion <NUM> is defined so as to be the same as a curvature of an outer membrane (for example, corneosclera) of an eyeball. The center of the curvature of the curved surface formed by the end portion <NUM> is defined in a region on the tubular portion <NUM> side outside the end portion <NUM>.

In the attachment tube <NUM> shown in <FIG>, the end portion <NUM> of the large diameter portion <NUM> is formed as a recessed curved surface that is inclined relative to the center axis L5, so that the end portion <NUM> and an external surface of an eyeball having a curved surface shape can be more advantageously brought into contact with each other.

In the above-described embodiment, an example in which the attachment tube is attached to a corneosclera is described. However, the attachment tube of this disclosure may be attached to a cornea peripheral portion <NUM> (see <FIG>) that is slightly closer to the center of the cornea than the corneosclera is. Furthermore, in vitreous surgery, the attachment tube of this disclosure may be attached to a sclera for communication between the vitreous body region and the outside of the eyeball. <FIG> illustrates an example in which the same attachment tube <NUM> as in <FIG> is attached to the sclera <NUM>. In <FIG>, the attachment tube <NUM> is attached to the sclera <NUM> such that the tubular portion <NUM> is oriented toward a retina. In this case, the portion 31a, closest to the leading end, of the end portion <NUM> of the large diameter portion <NUM> may be brought into contact with the external surface of the sclera <NUM> at the posterior side (side farther from the cornea), and the portion 31b closest to the proximal end may be brought into contact with the external surface of the sclera <NUM> at the anterior side (side closer to the cornea). In this structure, the large diameter portion <NUM> and the sclera <NUM> can be advantageously brought into contact with each other, so that the attachment tube <NUM> can be inhibited from becoming unstable.

Claim 1:
An eyeball attachment tube (<NUM>, <NUM>) that is temporarily attached to an outer membrane of an eyeball in ophthalmic surgery for communication between an inside and an outside of the eyeball, the eyeball attachment tube (<NUM>, <NUM>) comprising:
a tubular portion (<NUM>, <NUM>) formed in a tubular shape, the tubular portion (<NUM>, <NUM>) configured to be in a state of puncturing the outer membrane when the eyeball attachment tube (<NUM>, <NUM>) is attached to the outer membrane; and
a large diameter portion (<NUM>, <NUM>) disposed on a proximal end side of the tubular portion (<NUM>, <NUM>), the large diameter portion (<NUM>, <NUM>) having an outer diameter larger than an outer diameter of the tubular portion (<NUM>, <NUM>), the large diameter portion (<NUM>, <NUM>) configured to be exposed externally from the outer membrane when the eyeball attachment tube (<NUM>, <NUM>) is attached to the outer membrane, wherein
an end portion (<NUM>, <NUM>), in a parallel direction to a center axis (L1, L5) of the tubular portion (<NUM>, <NUM>), of the large diameter portion (<NUM>, <NUM>) on the tubular portion (<NUM>, <NUM>) side is shaped so as to have a height difference in the parallel direction between one end (31a, 11a) and another end (31b, 11b) in a direction perpendicular to the center axis (L1, L5) in a side view,
an entirety of the end portion (<NUM>, <NUM>) is formed as an inclined plane relative to the center axis (L1, L5), and
an end portion (<NUM>, <NUM>), of the large diameter portion (<NUM>, <NUM>), on an opposite side to the end portion (<NUM>, <NUM>) on the tubular portion (<NUM>, <NUM>) side in the parallel direction is formed as a plane perpendicular to the center axis (L1, L5), wherein the large diameter portion (<NUM>, <NUM>) includes a valve (<NUM>) for inhibiting liquid from flowing out from an opening (<NUM>) formed in the end portion (<NUM>, <NUM>) on the opposite side,
wherein the valve (<NUM>) is a member having a slit formed in an elastic material so as to close a channel (<NUM>) in the large diameter portion (<NUM>, <NUM>).