HK1237641B - Drainage device for controlling intraocular pressure in glaucoma - Google Patents

Description

Drainage devices used to control intraocular pressure in glaucoma

Technical Field

The present invention generally relates to a surgical treatment for glaucoma and, more particularly, to a stainless steel device that allows drainage of aqueous humor into the intrascleral and episcleral spaces, creating two virtual spaces that connect the anterior chamber with the intrascleral and episcleral spaces. This drainage allows for control of intraocular pressure and prevents blindness, pain, and other glaucoma-related conditions.

Background Art

Glaucoma is the second leading cause of blindness in the world after diabetes. Vision loss as a result of glaucoma affects both central and peripheral vision and has a significant impact on people's ability to live an independent life.

Glaucoma is a disorder of the optic nerve (optic nerve) caused by elevated intraocular pressure. High pressure inside the eye compresses the optic nerve's outlet (the papilla), causing changes in its appearance and visual function (optic cupping and changes in the visual field). If the pressure remains elevated for a sufficient period of time, complete and irreversible vision loss can occur.

Intraocular pressure is maintained by a balance between the production and outflow of aqueous humor. Aqueous humor is a fluid produced by the ciliary body in the posterior chamber of the eye at a rate of approximately 3 to 5 microliters per minute. This fluid then passes through the pupil of the iris and into the anterior chamber of the eye. Once in the anterior chamber, the fluid exits the eye through two distinct pathways: the uveoscleral pathway, which accounts for 10% of the outflow and is filtered between the muscle fibers of the ciliary body; and the canalicular pathway, which accounts for 90% of the outflow and is drained through the junction between the cornea and iris (the iridocorneal angle) via a filter called the trabeculae (which are composed of collagen bundles arranged in a three-dimensional structure similar to a sieve). From this point, the aqueous humor reaches the so-called Schlemm's canal (Schlenberg's canal) and then the episcleral veins.

Because the eye is a closed area, the production and outflow of aqueous humor must be equal. This creates a pressure within the eye that is determined by the amount of fluid produced and its capacity to flow out. Under normal conditions, intraocular pressure is between 10 and 21 mmHg.

If aqueous humor production increases relative to outflow resistance, then intraocular pressure will increase, forcing outflow. If outflow resistance increases, then intraocular pressure will increase, forcing outflow even with normal aqueous humor production. Both situations will increase intraocular pressure and may lead to glaucoma, as increases in outflow resistance are much more frequent.

Several factors can increase the resistance to aqueous humor outflow. Thus, in so-called "primary open-angle glaucoma" (which accounts for 85% of glaucoma cases), abnormal resistance develops along the outer aspects of the trabecular meshwork and the inner wall of Schlemm's canal. In "angle-closure glaucoma," this resistance is increased by mechanical obstruction of the angle, and in "secondary glaucoma," this resistance is increased for various reasons, such as the accumulation of inflammatory waste products, vascularization of the area, pigment obstruction, etc.

Regardless of the cause, increased intraocular pressure compresses the optic nerve's exit and interferes with its vascularization, leading to the death of nerve cells that transmit visual stimuli to the brain, changes in the visual field, and, in advanced cases, complete and irreversible blindness.

Currently the only treatment available for glaucoma is to reduce the intraocular pressure. The clinical treatment of glaucoma is carried out step by step. The first step is to take medical treatment orally or through drops.

Medications work by reducing aqueous humor production or by increasing its outflow. Currently available pharmaceutical products can have numerous side effects, some of which are serious and include congestive heart failure, respiratory distress, high blood pressure, depression, kidney stones, aplastic anemia, sexual dysfunction, and death. Compliance with medical advice is also a significant issue, with estimates that more than half of glaucoma patients do not correctly adhere to their medication regimen.

While the medication works, it will have the desired therapeutic effect, but it is often not enough to maintain a safe intraocular pressure and surgery is needed. The most frequently performed surgeries are trabeculoplasty and trabeculectomy.

During laser trabeculoplasty, thermal energy from a laser is applied to numerous discrete points within the trabecular meshwork. It is believed that the laser energy sometimes stimulates the metabolism of trabecular cells and alters the extracellular material of the trabecular meshwork. In approximately 80% of patients, aqueous humor outflow is increased and pressure is reduced. However, these effects are generally not long-lasting, and high pressure re-develops in 50% of patients within five years. Furthermore, laser trabeculoplasty is not an effective treatment for primary open-angle glaucoma in patients under 50 years of age, and is also ineffective for angle-closure glaucoma and many secondary glaucoma types.

If laser trabeculoplasty does not reduce the pressure to the desired level, filtering surgery is performed.

The most commonly performed filtration procedure is a trabeculectomy. During a trabeculectomy, an incision is made in the conjunctiva, the transparent tissue covering the sclera. The conjunctival tissue is lifted, and a scleral flap approximately 4 x 4 mm is formed to a depth of 50% of the scleral thickness. This flap is incised into the cornea as a thin flap down to a depth of 1 mm. The anterior chamber is introduced beneath the scleral flap, and a section of the deep sclera and trabecular meshwork is removed. The scleral flap is loosely sutured back into place, sealing the conjunctival incision well. After the procedure, aqueous humor passes through the hole under the scleral flap and into the subconjunctival space, where it forms a blister. From the blister, it reaches the blood vessels of the conjunctiva or passes through the conjunctiva to the surface.

Trabeculectomy is associated with a number of problems, among which fibroblasts present in the episcleral proliferation can migrate and scar the scleral flap, potentially leading to treatment failure, particularly in children and young adults. Of eyes that have undergone initial successful trabeculectomy, 80% will cease filtering within a period of 3 to 5 years after surgery. To minimize fibrosis, surgeons currently apply anti-fibrotic agents, such as mitomycin C (MMC) and 5-fluorouracil (5-FU), to the scleral flap during surgery. The use of these agents has increased the success rate of trabeculectomy, but has also increased its complications.

When trabeculectomy does not successfully reduce intraocular pressure, the next surgical step is usually an aqueous humor shunt valve. This device is made up of a silicone tube, one end of which is attached to a plastic (polypropylene or other synthetic material) plate with a valve shape, which is sutured to the midline of the eyeball or the part found behind it, and the other end of the silicone tube is introduced into the anterior chamber through the hole formed in the limbus. The outside of the silicone tube is covered with the sclera or pericardium from the donor, which is all covered by the conjunctiva, and the incision is closed. There are many problems in the current technology of these aqueous humor shunt valves, including poor therapeutic effect, valve failure, low intraocular pressure and infection.

In 1999, Optonol Ltd. patented a valveless tubular filter device for controlling intraocular pressure in glaucoma (Patent 5968058). This device is a small stainless steel tube that, once placed in the limbus, allows aqueous humor to flow from the anterior chamber through the tube into the intrascleral space and from there into the subconjunctival space. Alcon has been selling this device since 2002 under the name Ex-Press.

Implantation of these devices allows for a less invasive procedure than trabeculectomy because it does not require extracting a section of trabeculae or performing an iridectomy to allow aqueous humor to drain.

Several studies have reported the effectiveness of these devices for significantly reducing intraocular pressure, but complications have also been reported, the most common being flat eye and hemorrhage in the anterior chamber, which is believed to be related to the anchoring system.

All surgical techniques to lower intraocular pressure seek to create a new aqueous humor drainage pathway that replaces the obstructed normal pathway with the least amount of complications possible.

Summary of the Invention

According to the present invention, an integrated device for temporary drainage through the aqueous humor pressure of the eye is provided, the device comprising three parts: a first part located in the anterior chamber of the eye; a second part connecting the anterior chamber of the eye with the outside of the eye; and a third part located in the intrascleral space, the extrascleral space, or both the intrascleral space and the extrascleral space of the eye, in particular, the device is made of a metal or polymer material that cannot adhere to eye tissue, wherein the second part and the third part have the shape of a flat plate, the second part is located in an incision formed in the cornea, between the cornea and the sclera, wherein the device creates two virtual spaces that connect the anterior chamber with the intrascleral and extrascleral spaces, each of the two virtual spaces creating a unidirectional path through which aqueous humor will flow at a higher or lower speed, the higher or lower speed depending on the pressure gradient between the inside and the outside of the eye, so as to drain aqueous humor from the inside of the eye to the outside of the eye through the two virtual spaces to release excessive intraocular pressure caused by glaucoma.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 shows a three-dimensional view of the device object of the present invention, which has been divided into three parts: "A", "B" and "C". Part "A" will be placed in the anterior chamber between the cornea and the iris and will have a double triangular shape that allows for simple introduction and removal while keeping it fixed in place. Part "B" will pierce the eye in the limbus, being placed between the cornea and the sclera, while part "C" will be placed on the outside of the eye covered by the scleral flap, on the episclera, or in both places.

FIG2 shows a side view of the device object of the present invention, which has been divided into three parts: "A", "B" and "C". Part "A" will be placed in the anterior chamber between the cornea and the iris and will have a double triangular shape that allows for simple introduction and removal while keeping it fixed in place. Part "B" will pierce the eye in the limbus, while part "C" will be placed on the outside of the eye covered by the scleral flap, on the episclera, or in both places.

FIG3 shows a top view of the device object of the present invention, which has been divided into three parts: “A”, “B” and “C”. Part “A” will be placed in the anterior chamber between the cornea and the iris, part “B” will pierce the eye in the limbus, and part “C” (which may have variable measurements) will be placed outside the eye.

FIG4 shows a front view of the device object of the present invention, which has been divided into three parts: “A”, “B” and “C”. Part “A” will be placed in the anterior chamber between the cornea and the iris, part “B” will pierce the eye in the limbus, and part “C” (which may have variable measurements) will be placed outside the eye.

FIG5 is an illustration showing a sagittal cross-section of a human eye, depicting the anatomical details of the iridocorneal angle, which is the area to be affected by the present invention. The following structures can be seen: 1. Cornea; 2. Sclera; 3. Iris; 4. Limb; 5. Trabeculae; 6. Schlemm's Canal; 7. Lens.

Indication 8. Flap shows the area of the eye where the flap or scleral flap will be formed. Section "C" of the device will be placed between the scleral flap and the sclera, creating two virtual spaces: one facing the flap and the other facing the sclera. Aqueous humor will flow through these virtual spaces and disperse into the intrascleral space and the subconjunctival space.

FIG6 is an illustration of the device of the present invention in its operational position, wherein: Section "A" will be positioned in the anterior chamber. Section "B" will penetrate the eye, creating a virtual space upward between the cornea and the upper surface of the device, and a virtual space downward between the sclera and the lower surface of the device. Section "C" will be positioned externally of the eye between the scleral flap and the sclera, similarly creating two virtual spaces: one toward the flap and the other toward the sclera. Aqueous humor will flow through these virtual spaces and disperse into the intrascleral space and the subconjunctival space.

FIG7 is a diagram similar to that of FIG6 , but wherein portion “C” is longer and, in addition to being disposed between the scleral flap and the sclera, extends from the flap into the episcleral space, creating a virtual channel toward the midline of the eyeball, increasing the area for aqueous humor to spread. This can be advantageous in cases of neovascular glaucoma.

DETAILED DESCRIPTION

The present invention provides a device for permanent insertion into the scleral angle of the eye to reduce intraocular pressure and control glaucoma.

Since the device is a long-term implant, it must be made of materials that are harmless to the tissues and fluids it will come into contact with. The device must not be absorbed, corroded, or structurally damaged while being placed in place. It is also important that the presence of the implanted device does not negatively impact the tissues of the eye and the aqueous humor.

The device can be made of stainless steel or other biocompatible materials that will not adhere to the tissues of the eye, where such materials may include, but are not limited to, silicone or similar polymers, polytetrafluoroethylene, polypropylene or other thin-walled polymers. Metals and alloys known in the art for making implants may also be used. Importantly, the material used will not adhere to the tissues of the eye to create one or more virtual spaces from the anterior chamber to the outside of the eye, which may be the intrascleral space, the extrascleral space, or both. This space is virtual, not real, and creates a one-way path through which the aqueous humor will flow at a higher or lower rate, depending on the pressure gradient between the inside and outside of the eye. Because the drainage path is a virtual path, it minimizes the possibility of the chamber being flat or pathogens penetrating the device, and the anchoring system is not too sharp, thereby reducing the possibility of bleeding.

FIG1 shows a three-dimensional view of the device object of the present invention, which has been divided into three parts: "A", "B" and "C". The device will be made of stainless steel or another biocompatible material that will not adhere to the tissues of the eye, and will have a uniform or variable thickness. Part "A" will be placed in the anterior chamber between the cornea and the iris and will have a double triangular shape that allows for simple introduction and removal while keeping it fixed in place. Part "B" will pierce the eye in the limbus, being placed between the cornea and the sclera, while part "C" will be placed on the outside of the eye, covered by a scleral flap, on the episclera, or in both places.

FIG2 shows a side view of a device object of the present invention. The device will have a uniform or variable thickness and will have measurements between 0.02 mm and 0.3 mm. The device is a one-piece device, but for the purposes of this description it has been divided into three parts: "A", "B", and "C". Part "A" will be placed in the anterior chamber of the eye, between the cornea and the iris. Part "B" will pierce the limbus, creating two virtual spaces through which it will drain the aqueous humor, while part "C" will be placed outside the eye, either in the intrascleral space, in the episcleral space, or in both places. The parts that form the device of the present invention are:

Section "A":

FIG2 shows a side view of the filtering device, in which part "A" can be seen, which will be placed in the anterior chamber between the cornea and the iris (see FIG6 ). This part "A" will have a double triangular shape with an upper base "b" having measurements between 0.3 mm and 1.0 mm, a height "h" between 0.3 mm and 0.9 mm, and a rounded lower apex "v" to facilitate its insertion. This allows for less invasive anchoring, in addition to facilitating its introduction or removal.

FIG3 shows a top view of the device, in which section "A" can be seen. This section has a rectangular shape, where it connects to section "B" on the proximal side and becomes triangular on the distal side. The rectangular section will have a width equal to the width of section B, between 0.5 mm and 4 mm, and a length between 0.3 mm and 1.2 mm. The triangular distal section will have a base with the same width as the rectangular section and a height between 0.3 mm and 0.8 mm. These edges will be sharp to facilitate insertion.

Part "B":

FIG2 shows a side view of the filtering device, in which portion "B" is visible. This portion will pierce the limbus, creating a virtual space upward between the cornea and the upper surface of the device, and a virtual space downward between the sclera and the lower surface of the device. Aqueous humor will drain from the anterior chamber through these virtual spaces into the intrascleral or extrascleral space. The plate forming portion "B" of the device will have a thickness between 0.02 mm and 0.3 mm.

FIG3 shows a top view of the device, in which portion "B" can be seen, the upper surface of which will contact the cornea and form a virtual space with it through which the aqueous humor will flow. The lower surface will contact the sclera and form another virtual space. The surface of this plate can be smooth, rough, corrugated, grooved, or otherwise surface treated. Portion "B" of the device will have a length between 0.3 mm and 1.2 mm and a width equal to that of portion "A," which will measure between 0.5 mm and 4 mm.

Section "C"

Figure 2 shows a side view of the filter device, in which portion "C" can be seen. This portion will have a length between 0.5 mm and 15 mm and a thickness between 0.02 mm and 0.3 mm, will be thin, malleable, and will bend to approximate the curvature of the eye.

FIG3 shows a top view of the device, in which portion "C" can be seen, which is in the form of a rectangular plate with rounded edges and wider than portion "B." It will have a width measuring between 0.7 mm and 5 mm and a length measuring between 0.5 mm and 15 mm. This plate, which may be smooth, rough, corrugated, grooved, or otherwise surface-treated, will be placed on the exterior of the eye and covered by a scleral flap, placed in the episcleral space, or both.

Figure 5 is an illustration showing the area of the eye where a flap or scleral flap will be made to create a virtual space within the sclera. This flap will be similar to that obtained for a trabeculectomy and will have a length of approximately 4 mm, a width of 4 mm, and a depth of approximately 50% of the thickness of the sclera.

FIG6 is an illustration of the device of the present invention in its operational position, wherein portion "A" is positioned in the anterior chamber. Portion "B" penetrates the eye, creating a virtual space upward between the cornea and the upper surface of the device, and a virtual space downward between the sclera and the lower surface of the device. Portion "C" is positioned externally of the eye, between the scleral flap and the sclera, similarly creating two virtual spaces: one toward the flap and the other toward the sclera. Aqueous humor will flow through these virtual spaces and diffuse into the intrascleral and subconjunctival spaces.

FIG7 is a diagram similar to that of FIG6 , but wherein portion “C” is longer and, in addition to being disposed between the scleral flap and the sclera, projects from the flap toward the episcleral space, creating a virtual channel toward the midline of the eyeball, increasing the area for aqueous humor to spread. This can be very advantageous in cases of neovascular glaucoma.

The surgical procedure required to insert the device may include all or some of the following steps: 1. making an incision in the conjunctiva, which may be limbus-based or fornix-based, 2. defining the boundaries of a scleral flap, which is approximately 4 mm x 4 mm, has a thickness of approximately 50% of the thickness of the sclera, and is incised parallel to the sclera until 1 mm into the corneal tissue, 3. performing a puncture with the blade at 15° parallel to the limbus, 4. inserting the device into the puncture, 5. closing the flap with two loose sutures, 6. closing the conjunctiva.

Claims (6)

1. An integrated device for temporarily draining aqueous humor from the eye using pressure, the device comprising three parts: The first part is located in the anterior chamber of the eye; The second part connects the anterior chamber of the eye to the external rim; and The third part is located within the intrascleral space, extrascleral space, or both of the intrascleral and extrascleral spaces of the eye. The device is characterized by being made of a metal or polymer material that cannot adhere to eye tissues, wherein the second and third portions are plate-shaped, the second portion being located in an incision formed in the limbus between the cornea and sclera, wherein the device creates two virtual spaces that connect the anterior chamber with the intrascleral and extrascleral spaces, each of the two virtual spaces creating a unidirectional path through which aqueous humor will flow at a higher or lower speed depending on the pressure gradient between the inside and outside of the eye, to drain aqueous humor from the inside of the eye to the outside of the eye through the two virtual spaces to release excessive intraocular pressure caused by glaucoma. 2. The integrated device for temporary drainage by means of aqueous humor pressure of the eye according to claim 1, characterized in that the first part has a width between 0.5 mm and 4 mm and a length between 0.3 mm and 1.2 mm, and has a sharp edge to facilitate insertion of the first part. 3. The integrated device for temporary drainage by means of aqueous humor pressure of the eye according to claim 1, characterized in that the second part has a length between 0.3 mm and 1.2 mm, a width between 0.5 mm and 4 mm, and a thickness between 0.02 mm and 0.3 mm. 4. The integrated device for temporary drainage by means of aqueous humor pressure of the eye according to claim 1, characterized in that the third part has a length between 0.5 mm and 15 mm, a width between 0.7 mm and 5 mm, and a thickness between 0.02 mm and 0.3 mm. 5. The integrated device for temporary drainage via the aqueous humor pressure of the eye according to claim 1, characterized in that the device is made of stainless steel. 6. The integrated device for temporarily draining aqueous humor by means of pressure in the eye, as claimed in claim 1, characterized in that the device is made of a metal alloy.