Device For Ablation Processing Of Ophthalmological Implantation Material

Abstract

A device for ablation processing of ophthalmological implantation material, which is formed by water-containing base material, comprises a laser source, which is configured to generate a pulsed laser beam having a processing wavelength in the ultraviolet wavelength range, wherein the processing wavelength is greater than 193 nm and causes a higher absorptance of the laser beam in the base material of the implantation material than the absorptance of the laser beam in the water of the implantation material is described.

Claims

1. A device for ablation processing of ophthalmological implantation material, which is formed by water-containing base material, comprising: a laser source configured to generate a pulsed laser beam having a processing wavelength in the ultraviolet wavelength range, wherein the processing wavelength is greater than 193 nm and causes a higher absorptance of the pulsed laser beam in the base material of the implantation material than absorptance of the laser beam in the water of the implantation material; a projection lens configured to radiate the pulsed laser beam onto a surface of the implantation material, and, in a processing region, to trigger an interaction with the implantation material for ablation of the implantation material using laser pulses of the laser beam, wherein the laser pulses have a combination of pulse duration and intensity causing photoablation; and a scanner device configured to execute a movement of the processing region for the ablation processing according to a processing pattern.

2. The device of claim 1, wherein the processing wavelength is delimited in a lower wavelength range by a maximum absorptance of 10.sup.−2/cm of the laser beam in the water of the implantation material and is delimited in a higher wavelength range by a minimal absorptance of 10.sup.0/cm of the laser beam in the base material of the implantation material.

3. The device of claim 1, wherein the processing wavelength is greater than 200 nm.

4. The device of claim 1, wherein the processing wavelength is in a range of 200 nm to 250 nm.

5. The device of claim 1, wherein the pulse duration is in a pulse duration range of 10.sup.−9 seconds to 10.sup.−6 seconds.

6. The device of claim 1, wherein the intensity is in an intensity range of 10.sup.7 W/cm.sup.2 to 10.sup.10 W/cm.sup.2.

7. The device of claim 1, wherein the laser source and the projection lens are further configured to radiate the pulsed laser beam with a fluence in a fluence range of 10.sup.6 W/cm.sup.2 and 10.sup.10 W/cm.sup.2 onto the surface of the implantation material.

8. The device of claim 1, further comprising: an air humidifier; an humidity sensor; and a control unit, interconnected to the air humidifier and the humidity sensor, comprising an electronic circuit configured to control the air humidifier as a function of an humidity value measured by the humidity sensor in a surroundings region adjacent to the implantation material in such a way that a predetermined minimum humidity value is maintained.

9. The device of claim 8, wherein the electronic circuit further is configured to control the air humidifier in such a way that a minimum humidity value of 95% relative humidity is maintained.

10. The device of claim 1, wherein the scanner device further is configured to execute the movement of the processing region for ablation processing according to the processing pattern to generate a lenticular surface.

11. The device of claim 1, wherein the scanner device comprises at least one movable mirror configured to deflect the pulsed laser beam for the movement of the processing region according to the processing pattern.

12. The device of claim 11, wherein the scanner device is arranged downstream of the projection lens.

13. The device of claim 1, wherein the scanner device comprises at least one drive configured to displace the projection lens in order to execute the movement of the processing region according to the processing pattern.

14. The device of claim 1, wherein the scanner device comprises at least one drive configured to displace a material carrier, on which the implantation material is applied, in order to execute the movement of the processing region according to the processing pattern.

15. A method for ablation processing of ophthalmological implantation material, which is formed by water-containing base material comprising: generating a pulsed laser beam having a processing wavelength in the ultraviolet wavelength range, wherein the processing wavelength is greater than 193 nm and causes a higher absorptance of the pulsed laser beam in the base material of the implantation material than absorptance of the laser beam in the water of the implantation material; radiating the pulsed laser beam onto a surface of the implantation material; triggering, in a processing regions, an interaction with the implantation material for ablation of the implantation material using laser pulses of the laser beam, wherein the laser pulses have a combination of pulse duration and intensity causing photoablation; and executing a movement of the processing region for the ablation processing according to a processing pattern.

16. The method of claim 15, further comprising controlling an air humidifier as a function of a humidity value measured by a humidity sensor in a surroundings region adjacent to the implantation material in such a way that a predetermined minimum humidity value is maintained.

17. The method of claim 16, controlling the air humidifier in such a way that a minimum humidity value of 95% relative humidity is maintained.

18. The method of claim 15, further comprising executing the movement of the processing region for ablation processing according to the processing pattern to generate a lenticular surface.

19. The method of claim 15, further comprising deflecting the pulsed laser beam for the movement of the processing region according to the processing pattern.

20. The method of claim 15, further comprising displacing a material carrier, on which the implantation material is applied, in order to execute the movement of the processing region according to the processing pattern.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] An illustrative example of the present disclosure is described hereinafter on the basis of an example. The example of the illustrative example is illustrated by the following appended figures:

[0022] FIG. 1 schematically shows a cross section of a block diagram having illustrative example variants of a device for ablation processing of ophthalmological implantation material.

[0023] FIG. 2 schematically shows a cross section of a block diagram having further illustrative example variants of a device for ablation processing of ophthalmological implantation material.

[0024] FIG. 3 shows a graph which illustrates the absorption of laser light in water and in protein forming the base material of the cornea as a function of the wavelength of the laser beam.

[0025] FIG. 4 shows a graph which illustrates the parameter ranges of various material processing methods by means of lasers.

DETAILED DESCRIPTION

[0026] In each of FIGS. 1 and 2, the reference sign 1 refers to a device for ablation processing, in particular a device for ablation processing of ophthalmological implantation material 2, in particular of water-containing ophthalmological implantation material 2. The ophthalmological implantation material 2 thus comprises base material and water. The ophthalmological implantation material 2 comprises natural donor tissue, for example human corneal tissue (cornea) having protein(s) as the base material, or synthetic tissue, for example hydrogels, which comprise polymers containing water.

[0027] As schematically shown in FIGS. 1 and 2, the device 1 comprises a laser source 11, a projection lens 12, a scanner device 13, 13′, and a control unit 14 having an electronic circuit 15. The control unit 14 or the electronic circuit 15, respectively, is interconnected via signal and/or control lines to the laser source 11, the projection lens 12, and the scanner device 13, 13′ for their control.

[0028] The laser source 11 is configured to generate a pulsed laser beam L having a processing wavelength λ in the ultraviolet wavelength range, as explained and defined in greater detail hereinafter. The projection lens 12 is configured to radiate the pulsed laser beam L onto a surface 20 of the implantation material 2 and to trigger an interaction with the implantation material 2 for ablation of the implantation material 2 in a processing region 21 using laser pulses P of the laser beam L. For this purpose, the laser pulses P generated by the laser source 11 and radiated by the projection lens 12 onto the surface 20 of the implantation material 2 have a combination of pulse duration D and intensity I in a parameter range PA, which effectuate photoablation (see FIG. 4).

[0029] As is additionally schematically shown in FIGS. 1 and 2, the device 1, in one illustrative example variant, comprises an humidity sensor 17 and an air humidifier 16, which are attached, for example, in a closed humidity chamber 160. The humidity sensor 17 and the air humidifier 16 are interconnected via a signal line 171 or via a control line 161 to the control unit 14 or to its electronic circuit 15, respectively. The electronic circuit 15 is embodied as a programmed processor, as an application-specific integrated circuit (ASIC), or as another electronic logic unit.

[0030] The electronic circuit 15 ascertains, via the signal line 171, the relative humidity measured by the humidity sensor 17 in the surroundings region U of the implantation material 2 to be processed. The electronic circuit 15 is configured to control the air humidifier 16 as a function of the measured humidity value in such a way that a predetermined minimum humidity value is maintained. A water tank and/or a water conduit for supplying water to the air humidifier 16 is not shown in FIGS. 1 and 2. The minimum humidity value is, for example, at least 90% relative humidity, in particular 95% relative humidity. The optional humidity chamber 160 schematically shown in FIGS. 1 and 2 simplifies and increases the accuracy of the relative humidity to be maintained.

[0031] The laser source 11 is configured to generate a pulsed laser beam L having a wavelength λ in the ultraviolet wavelength range, wherein the wavelength λ is greater than 193 nm. The laser source 11 is moreover configured to generate the pulsed laser beam L having a wavelength λ in a wavelength range, in which the wavelength λ causes a higher absorptance A of the pulsed laser beam L in the base material of the implantation material 2 than in the water of the implantation material 2, for example in an operating range BB according to FIG. 3. The laser source 11 is thus configured to generate the pulsed laser beam L having a processing wavelength λ, which is greater than 193 nm, i.e., greater than the wavelength of known ArF excimer lasers, on the one hand, and has a higher absorptance A in the base material of the implantation material 2 than in water, on the other hand.

[0032] This relationship of wavelength λ and absorptance A in the base material of the implantation material 2, on the one hand, and in water, on the other hand, is shown in FIG. 3. FIG. 3 illustrates, as a function of the wavelength λ of the laser beam L, the absorptance A of laser light in water and in protein, as an example of base material of the cornea. The profile of the absorptance A as a function of the wavelength λ is shown for water using the curves WH, W, and WL. The wavelength-dependent absorption curves WH and WL for water illustrate a value range having a high or low absorption rate, respectively, of light in water. The wavelength-dependent absorption curve W for water corresponds to a mean absorptance of light in water. The different wavelength-dependent absorption curves WH, W, and WL are defined, on the one hand, by different degrees of purity of the water and different measurement conditions. The profile of the absorptance A as a function of the wavelength λ is shown for protein as the base material of the cornea using the curves CH, C, and CL. The wavelength-dependent absorption curves CH and CL for protein (cornea) illustrate a value range having a high or low absorption rate, respectively, of light in the protein (cornea). The wavelength-dependent absorption curve C for protein (cornea) corresponds to a mean absorptance of light in the protein (cornea). The different wavelength-dependent absorption curves CH, C, and CL are defined in particular by different measurement conditions.

[0033] The reference sign BB in FIG. 3 identifies the operating range for the laser source 11 of the device 1. As illustrated in FIG. 3, the operating range BB is determined, on the one hand, by the profile of the wavelength-dependent absorption curves WH, W, and WL for water and, on the other hand, by the wavelength-dependent absorption curves CH, C, and CL for protein (cornea), for example by the mean wavelength-dependent absorption curve W for water and the mean wavelength-dependent absorption curve C for protein (cornea). The operating range BB for the laser source 11 is determined so that the absorption A of the pulsed laser beam L in the protein (cornea) as a function of the wavelength λ is always greater than in water. In the lower wavelength range, at approximately 200 nm, the operating range BB is delimited by the steep increase of the absorptance A in the water for wavelengths below this (in the range identified by BL). In the upper wavelength range, the operating range BB is delimited by the drop of the absorptance A in the protein (cornea) at approximately 250 nm. The absorptance CL in the protein (cornea) approaches the absorptance in the water WH there in such a way that in the extreme case (in the range identified by BH), when the wavelength-dependent absorption curve WH having a high absorptance in water and the wavelength-dependent absorption curve CL having a low absorptance CL in the protein (cornea) are taken into consideration, the difference in the absorption rates in water WH and in the protein (cornea) CL falls to a factor less than 10.sup.2 and approaches the factor 10.sup.1.

[0034] FIG. 1 schematically shows an exemplary illustrative example, in which a scanner device 13 having one or more movable mirrors 131 for deflecting the pulsed laser beam L is interconnected downstream of the projection lens 12. In this case, the pulsed laser beam L is prepared (focusing/converging) by the projection lens 12 for the irradiation of the surface 20 in a processing region 21 of the implantation material 2 to be treated. The processing region 21 is moved by the scanner device 13 by deflection of the pulsed laser beam L by means of one or more movable mirrors 131 according to a processing pattern, for example to generate a lenticular surface of a lenticule to be produced from the implantation material 2.

[0035] FIG. 2 schematically shows an exemplary illustrative example in which the scanner device 13 having one or more movable mirrors 131 is interconnected upstream of the projection lens 12.

[0036] In further illustrative example variants, the scanner device 13 comprises one or more drives 132 for displacing the projection lens 12 in order to execute the movement of the processing region 21 according to the processing pattern.

[0037] A further alternative illustrative example variant of the scanner device 13′ is illustrated schematically both in FIG. 1 and also in FIG. 2. The scanner device 13′ comprises one or more drives 132′, which are configured to displace a material carrier 131′, on which the implantation material 2 to be processed is applied, in order to execute the movement of the processing region 21 according to the processing pattern.