Additive manufacturing inside the human eye

Abstract

Additive manufacturing techniques are used to form an artificial intra-ocular lens (IOL) directly inside the human eye. Small openings are formed in the cornea and lens capsule of the eye, and the crystalline lens is broken up and removed through the openings; then, a material is injected into the lens capsule through the openings, and the focal spot of a pulse laser beam is scanned in a defined pattern in the lens capsule, to transform the material in the vicinity of the lase focal spot to form the IOL in a layer-by-layer manner. In one embodiment, stereolithography techniques are used where a pulse UV laser source is used to photosolidify a photopolymer resin. The liquefied resin is injected into the eye through the openings, after which only part of the resin, having the shape of the desired IOL, is selectively cured with the UV laser beam, via progressive layer formation.

Claims

1. A method for forming an artificial intra-ocular lens (IOL) inside a patient's eye, comprising: using a pulse laser beam from a laser system to form an opening in a cornea and an opening in a lens capsule of the patient's eye; using the pulse laser beam from the laser system to break up a crystalline lens of the eye from the lens capsule; removing the broken up crystalline lens through the openings in the cornea and the lens capsule; injecting a material into the lens capsule through the openings in the cornea and the lens capsule; and forming said artificial IOL directly inside the lens capsule by scanning a focal spot of the pulse laser beam from the laser system inside the lens capsule in a defined scanning pattern to transform the material in a vicinity of the focal spot of the pulse laser beam; wherein the material includes unassembled individual slices of the IOL, wherein the injecting step includes incrementally injecting the individual slices into the lens capsule, wherein the forming step includes scanning the focal spot of the pulse laser beam to incrementally assemble injected individual slices together, and wherein the individual slices include slices of polymethylmethacrylate, and wherein the forming step includes scanning the focal spot of the pulse laser beam to melt surface layers of the polymethylmethacrylate slices.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates a laser system that may be employed to implement embodiments of the present invention.

(2) FIGS. 2A-2D schematically illustrate methods for forming an artificial IOL using additive manufacturing inside the human eye according to embodiments of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(3) Various techniques may be employed for intra-body-manufacturing, and in particular, for manufacturing IOLs inside the eye. Some of these techniques use a laser source to either etch the material into shape, or to selectively cure it into shape.

(4) In a first embodiment, stereolithography techniques are used, where a pulse UV laser source is used to photosolidify a photopolymer resin. The liquefied resin is injected into the eye by a small opening in the eye, after which only part of the resin, having the shape of the desired IOL, is selectively cured with the UV laser beam, via progressive layer formation. The rest to the polymer is removed, or absorbed.

(5) More specifically (see FIG. 2A), using a pulse laser surgery system, a single small opening is cut into the cornea and a capsulotomy of desired shape is cut into the surface of the human crystalline lens (lens capsule) (step S1). Subsequently, the human crystalline lens is broken up (phacofragmentation) using a laser beam, or using ultrasound energy by a phaco-emulsification tip (step S2), and the fragments are suctioned out (step S3). The same openings to the cornea and lens capsule are used to inject a drop of photopolymer resin into the lens capsule (step S4A). Then, a pulse laser beam is focused at a desired depth, and scanned in a lateral plane across a defined area within the volume of resin in the lens capsule (step S5A). Curing of the resin occurs in the vicinity of the focal spot of the laser beam where sufficient energy density is present. By scanning the focal spot across a defined area in a plane, a solidified resin layer having the defined shape is formed. After forming a layer, the focal spot depth of the laser beam is adjusted, and the beam is scanned at the new depth across another defined area, to form another solidified layer of resin on the surface of the previously formed layer. The scanning step is repeated to progressively solidify a part of the liquefied resin into the desired 3D shape of an IOL with the desired prescribed power and astigmatic correction.

(6) Various ophthalmic laser surgery systems are known and may be used to perform stereolithography in this embodiment. An ophthalmic laser surgery system uses a laser delivery system to deliver a laser beam generated by a laser into a patient's eye. The laser delivery system focuses the laser beam and scans the focal spot over an area or volume of the eye (referred to as the treatment area or region) to achieve desired therapeutic effects, such as photoalteration of the eye tissues. FIG. 1 is a block diagram that schematically illustrates an ophthalmic laser surgery system 10. The system 10 includes a laser 14 capable of generating a pulsed laser beam 18, an energy control module 16 for controlling and varying the pulse energy of the pulsed laser beam 18, a scanner 20 for scanning the laser beam, focusing optics 28 for directing the pulsed laser beam 18 on the surface of or within the region 12 (e.g., sub-surface) of the patient's eye, an imaging system 34 for displaying a real-time digital image of the patient's eye and providing other information, a controller 22, and a user interface 32 for the operator to interact with the system. The scanner 20 is controlled by the controller 22 to scan the focal spot of the laser beam within the eye. The controller 20 includes a processor and a memory device storing data and program code, including data and program code for controlling the scanner 20 to scan the laser beam according to defined scan patterns. The system 10 also includes a beam splitter 26 and a detector 24 coupled to the controller 22 to provide a feedback control mechanism for the pulsed laser beam 18. The laser 14 may be, for example, an ultrashort pulse laser, e.g. a femtosecond laser that can output a pulsed laser beam having a pulse width in the picosecond to femtosecond range. In some systems, some components, such as the beam splitter 26 and detector 24, may be omitted; some other systems may include additional components not shown in FIG. 1, such as a range finding system, etc.

(7) In this embodiment, any suitable photopolymer resin may be used. Many known materials are suitable for this purpose. For example, U.S. Pat. Appl. Pub. No. 2009/0250828 describes a method for making ophthalmic devices using single mold stereolithography outside of the eye. This publication describes a number of photocurable materials that can be cured by UV light for purpose of making the ophthalmic devices, such as water-soluble crosslinkable poly(vinyl alcohol) prepolymer, more specifically, a polyhydroxyl compound.

(8) The pulse laser used to photosolidify the resin may be the same pulse laser used to form the corneal incision, capsulotomy and phacofragmentation, or a different laser. The parameters (e.g. pulse energy, pulse duration, pulse repetition rate, wavelength) of the laser pulses suitable for this step may be determined based on the properties of the photopolymer resin used. The scan pattern of the laser focal spot for each layer is determined based on the properties of the photopolymer resin and the desired shape of the IOL to be formed. Note that the shape of the IOL is determined by the scan patterns for each layer, not by the shape of the liquefied resin inside the lens capsule.

(9) To prevent the partially formed IOL from moving in the lens capsule during laser scanning, which would impact the accuracy of the shape of the formed IOL, a temporary anchor structure, such as two haptics, may be formed early in the photosolidification process. The anchor structure extends to the lens capsule to prevent movement of the partially formed IOL. The temporary anchor structure may be removed after the IOL is formed, or it may be kept as a part of the haptic of the finally formed IOL.

(10) In a second embodiment (see FIG. 2B), referred to as selective layer sintering, a body of polymer is progressively formed inside the eye, in a layer-by-layer manner, by progressively fusing a polymer together (step S5B). A pulse UV laser is used to fuse the material into shape. This technique differs from the stereolithography technique (first embodiment) in that the polymer is not cured but melted by the laser beam and fused together. An example of a polymer that may be useful in this embodiment is acrylic powder which may be injected into the eye (step S4B). Other aspects of the second embodiment are similar to those of the first embodiment.

(11) In a third embodiment (see FIG. 2C), referred to as laminated object manufacturing, fractional parts of an IOL, such as individual thin layers (slices) of an IOL, are introduced into the eye through the openings in the cornea and the lens capsule (step S4C). Once two parts are inserted inside the eye, they are assembled together (step S5C). Incremental insertion and assembling of additional IOL layer eventually lead to the complete assembly of the IOL. Compared to conventional technologies which insert a single monolithic IOL, only smaller parts are inserted using this technique; thus, comparatively small corneal openings are required. A material that may be useful in this embodiment is PMMA (polymethyl methacrylate), and the slices may be assembled by melting a surface thin layer of the material by scanning a pulsed laser beam across the surface (step 5C). Other aspects of the third embodiment are similar to those of the first embodiment.

(12) Stated more generally (see FIG. 2D), in the above embodiments, after forming openings in the cornea and lens capsule (step S1), breaking up the crystalline lens (step S2), and removing fragments of crystalline lens from the lens capsule through the openings (step S3), a material, such as a polymer, fractional parts of the IOL, etc., is injected into the lens capsule through the openings in the cornea and the lens capsule formed in step S1 (step S4D). Then, a pulse laser beam is focused at desired depths and the focal spot is scanned across defined areas relative to the material in the lens capsule (step S5D), such that the material is transformed either physically or chemically or both in a layer by layer manner to form an IOL. The scan pattern of the laser beam is controlled by the controller 20 which executes program code stored in its memory.

(13) In a fourth embodiment, referred to as laser etching, an existing lens can be reshaped so as to adjust the correction after the original surgery. For example, if after surgery, the residual astigmatism is 1 diopter, then a pulse laser beam may be used to remove additional IOL materials in a manner that reshapes the IOL and modifies its optical properties. In this particular example the IOL prescriptive power is adjusted by 1 diopter.

(14) Using these techniques, an IOL can be built inside the anterior chamber of the eye, through a minuscule hole, just large enough to introduce a manufacturing tip or individual smaller/thinner parts of the IOL. In some of the described techniques, the same laser used to perform preliminary steps of the procedure (such as capsulotomy) is used to interact with the material to form the IOL.

(15) Using the same principles and techniques described above, other implantable devices such as stents, etc. may be manufactured inside the human body. The laser beam may be introduced to the manufacturing site by a catheter and/or an optical fiber.

(16) It will be apparent to those skilled in the art that various modification and variations can be made in the method and apparatus for performing additive manufacturing inside the human eye according to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover modifications and variations that come within the scope of the appended claims and their equivalents.