Surgical treatment for glaucoma
View Patent ↗A glaucoma treatment apparatus including an imaging device capable of imaging the anterior segment of the eye, a treatment laser, an algorithm programmed to determine a location and a cross sectional area of a treatment based on a customized anatomy of the anterior segment of the eye including the trabecular meshwork (TM), the Schlemm's Canal (SC) and collector channels (CCS), obtained from pre-operative images of the anterior segment of the eye, a pre-operative intraocular pressure (IOP) level and a target IOP reduction as an inputs, and a processor configured to actuate the apparatus to create an outflow channel with a cross-sectional area and location or multiple outflow channels with multiple cross-sectional areas and locations from the anterior chamber (AC) to the SC across the TM, as determined by the algorithm to achieve the target intraocular pressure (IOP) reduction. Also disclosed is a method of reducing intraocular pressure in an eye.
1 . A glaucoma treatment apparatus comprising:
an imaging device configured to image an anterior segment of the eye,
a laser, and
a hardware processor configured to:
(a) determine a location and a cross sectional area of a treatment based on an anatomy of the anterior segment of the eye obtained from pre-operative images of the anterior segment of the eye, a pre-operative intraocular pressure (IOP) level, and a target IOP reduction, said anatomy including the trabecular meshwork (TM), juxtacanalicular tissue (JCT), the Schlemm's Canal (SC) and collector channels (CCS), wherein the hardware processor is configured to use a three-dimensional (3D) finite element model (FEM) computer model of aqueous humor (AH) outflow dynamics, wherein the 3D FEM uses the anatomy of the TM, JCT, SC and CCS obtained from pre-operative images, the pre-operative IOP and the target IOP reduction as inputs, and calculates the optimal location and cross sectional area of the channels to be created by a femtosecond (FS) laser in order to achieve the target IPO, wherein the 3D FEM model is based on the following assumptions:
(i) the amount of AH flowing out of the eye through the uveoscleral pathway is not exactly known, but is generally considered to be much less than the outflow through the conventional or trabecular pathway and it is assumed that all the AH outflow occurs through the trabecular pathway;
(ii) the trabecular pathway in the eye is porous, so that outflow through the pathway follows the Brinkman equation and its resistance to outflow can be characterized with permeability in the equation;
(iii) the resistance of pathways through TM, juxtacanalicular tissue (JCT) and inner wall endothelium of the SC are characterized by different permeability values since the JCT and inner wall endothelium of the SC are the major barrier to the outflow;
(iv) the structures of the eye, including the cornea, are rigid materials, and for the precise estimation of the AH outflow parameters deformation of the cornea and movement of the structural components such as lens and iris inside the eye are included in the FEM of the AH outflow; and
(v) the potential impact of temperature on the AH outflow is not considered; and
(b) actuate the laser to ablate specifically mapped regions of the TM, the JCT and the SC to create one or more aqueous humor (AH) outflow drainage channel(s) with cross-sectional area and location in order to achieve the target IOP reduction.
2 . The glaucoma treatment apparatus according to claim 1 , further comprising a suction ring configured to keep the apparatus steady on the eye during a treatment procedure.
3 . The glaucoma treatment apparatus according to claim 1 , wherein the apparatus is configured to automatically create drainage channels in between the anterior chamber (AC) and the SC, based on output from the hardware processor.
4 . The glaucoma treatment apparatus according to claim 1 wherein the treatment laser has a pulse duration ranging from 50 fs to 50 ns.
5 . The glaucoma treatment apparatus according to claim 1 , wherein the treatment laser has a repetition rate ranging up to 500 KHz.
6 . The glaucoma treatment apparatus according to claim 1 , wherein the imaging device is selected from the group consisting of a light microscope, an ultrasound device, a computed tomography (CT) device, a magnetic resonance imager (MRI), a system that utilizes molecular imaging, a system that utilizes nuclear medicine, a positron emission tomography (PET) system, a radiography system, and a fluoroscopy system.
7 . The glaucoma treatment apparatus according to claim 1 , wherein in the 3D FEM, the anterior chamber is modeled as a hemisphere.
8 . The glaucoma treatment apparatus according to claim 7 , wherein the hemisphere is modeled with a diameter of 12 mm along the edge of the iris.
9 . The glaucoma treatment apparatus according to claim 1 , wherein in the 3D FEM, the height of the TM is modeled to range from 0.38 to 0.86 mm.
10 . The glaucoma treatment apparatus according to claim 9 , wherein in the 3D FEM, the height of the TM is modeled to have an average height of 0.6 mm.
11 . The glaucoma treatment apparatus according to claim 1 , wherein in the 3D FEM, the final destination of aqueous humor (AH) flow is modeled to have a constant pressure boundary condition of 9.6 mmHg, corresponding to the back-pressure in the episcleral venous system.
12 . The glaucoma treatment apparatus according to claim 1 , wherein the 3D FEM is based on the Navier-Stokes equation and continuity equations, where the AH is described as incompressible fluid, modified to describe steady state flow and to describe AH dynamics in the model:
−∇[η(∇ u +(∇ u ) T )]+ρ u ∇ u +∇P= 0,∇ u = 0, and
wherein flow through the trabecular meshwork is governed by the steady state Brinkman equation:
-
∇
[
η
(
∇
u
¯
+
(
∇
u
¯
)
T
)
]
+
∇
P
+
η
κ
u
¯
=
0
,
∇
u
¯
=
0
,
where u is velocity (m/s), ρ is density (kg/m 3 ), η is dynamic viscosity (Pa* second), and k is permeability (m 2 ).
13 . A method of reducing intraocular pressure in an eye comprising:
acquiring a pre-operative image of the anterior segment of the eye using the glaucoma treatment apparatus according to claim 1 , including the TM, the SC and the CCS,
using the 3D FEM to determine a location and a cross-sectional area of treatment or various locations and a cross-sectional area of multiple treatments in the trabecular meshwork of the eye that will allow precise personalized control over intraocular pressure reduction,
targeting the TM, the JCT and the SC with laser pulses of short durations to create drainage channels in between the AC and the SC, and
draining of aqueous humor from the anterior chamber to the SC to reduce intraocular pressure in the eye, wherein the channels mediate precise and customized control over the magnitude and/or rate of drainage of the aqueous humor into the SC.
14 . The glaucoma treatment method according to claim 13 , wherein the laser pulses of short durations used for the treatment range from 50 fs to 50 ns.
15 . The glaucoma treatment method according to claim 13 , wherein a repetition rate of the laser pulses of short durations used for the treatment ranges up to 500 KHz.