APPARATUS FOR PROVIDING RETINAL THERAPY, METHOD FOR TRACKING A CHANGE IN RETINAL CELLS' FUNCTIONAL MODIFICATION

Abstract

The invention concerns an confocal scanning laser ophthalmoscope for providing retinal therapy of an eye comprising: a first light source configured to emit a treatment beam with a first wavelength to a selected area of the retina, whereby the retina is external to the confocal scanning laser ophthalmoscope; a retinal functional tracking means comprising a second light source and a detector, wherein the second light source is arranged to emit light within a spectrum to the selected area of the retina, and wherein the detector is configured to analyse reflected light by the retina at the selected area, wherein the detector is adapted to determine a change in the spectrum of the reflected light; and wherein the confocal scanning laser ophthalmoscope is configured to adapt a therapeutic dose emitted by the first light source in response to the determination of a change in the spectrum of the reflected light.

The invention also concerns a method for detecting a change in retinal cells of an eye stimulated by a light beam of a first light source.

Claims

1. A confocal scanning laser ophthalmoscope for providing retinal therapy of an eye comprising: a first light source configured to emit a treatment beam with a first wavelength to a selected area of the retina, whereby the retina is external to the apparatus; a retinal functional tracking means comprising a second light source and a detector, wherein the second light source is arranged to emit light within a spectrum to the selected area of the retina, and wherein the detector is configured to analyse reflected light by the retina at the selected area, wherein the detector is adapted to determine a change in the spectrum of the reflected light; and wherein the apparatus is configured to adapt a therapeutic dose emitted by the first light source in response to the determination of a change in the spectrum of the reflected light.

2. The confocal scanning laser ophthalmoscope of claim 1, wherein the therapeutic dose is characterised by at least one parameter of the first light source including radiant power, irradiance, exposure duration, fluence, and/or repetition intervals.

3. The confocal scanning laser ophthalmoscope of claim 1, wherein the first light source is configured to emit a plurality of consecutive treatment light pulses within an exposure duration, wherein each treatment light pulse is characterised by an peak radiant power, a pulse period and a pulse width, wherein the exposure duration corresponds to the time required to conclude the treatment of the selected area of the retina.

4. The confocal scanning laser ophthalmoscope of claim 3, wherein the therapeutic dose is characterised by the peak radiant power, the pulse width and/or the number of consecutive pulses within the exposure duration.

5. The confocal scanning laser ophthalmoscope of claim 1, wherein the change in the spectrum of the reflected light is caused by the treatment of retinal cells while energising the first light source for applying the therapeutic dose.

6. The confocal scanning laser ophthalmoscope of claim 1, comprising a control device connected to the first light source and the retinal functional tracking means and configured to control the at least one parameter of the first light source in response to the determination of a change in the spectrum of the reflected light.

7. The confocal scanning laser ophthalmoscope of claim 6, wherein the control device is configured to control the at least one parameter of the first light source while the first light source emits a therapeutic dose to the retina and/or after the emission of a therapeutic dose.

8. The confocal scanning laser ophthalmoscope of claim 7, wherein the control device controls the parameter of the first light source related to at least one treatment objective, wherein the at least one treatment objective is characterised by the thermal, biochemical and/or systemic and collective cellular activation of retinal cells.

9. The confocal scanning laser ophthalmoscope of claim 1, wherein the spectrum of the light emitted by the second light source includes light in a wavelength between 700 nm and 1400 nm, more preferably between 700 nm and 1000 nm and most preferably between 700 nm and 900 nm.

10. The confocal scanning laser ophthalmoscope of claim 1, wherein the wavelength of the light emitted by the first light source is light of a specific wavelength selected in a range from 785 nm to 845 nm, more preferably from 805 nm to 840 nm and most preferably from 825 nm to 835 nm.

11. Method for detecting a change in retinal cells' functional modification of an eye stimulated by a light beam of a first light source, comprising the steps of: Emitting a light beam with a first wavelength to a selected area of a retina; Emitting a functional excitation beam to the selected area of the retina, wherein the functional excitation beam includes light within a spectrum; Receiving reflected light from the selected area of the retina within the spectrum; Determining a change in the spectrum of the reflected light, in particular caused by an activation of mitochondrial respiration activities of retinal cells.

12. Method for detecting a change in retinal cells' of claim 11, further comprising the step of adapting a parameter of a dose of light in response to the determination of a change in the spectrum of the reflected light.

13. Method for detecting a change in retinal cells' of claim 11, wherein the light beam and the functional excitation beam are emitted simultaneously.

14. Method for detecting a change in retinal cells' of claim 11, wherein the step for determining a change in the spectrum of the reflected light is performed while and/or after emitting the dose of light.

15. Method for detecting a change in retinal cells' of claim 11, wherein the method is carried out from a confocal scanning laser ophthalmoscope.

Description

SHORT DESCRIPTION OF THE DRAWINGS

[0089] Exemplar embodiments of the invention are disclosed in the description and illustrated by the drawings in which:

[0090] FIG. 1a illustrates a confocal scanning laser ophthalmoscope according to the invention schematically.

[0091] FIG. 1b illustrates the tissue stimulation by the treatment beam and the corresponding reaction of the cells.

[0092] FIG. 2 illustrates an optical treatment and functional tracking optical module of the confocal scanning laser ophthalmoscope according to the invention schematically.

[0093] FIG. 3 shows a total therapeutic dose in the form of a repetition of light pulses schematically.

[0094] FIG. 4 illustrates an optical power module of the confocal scanning laser ophthalmoscope according to the invention schematically.

[0095] FIG. 5 shows a possible configuration of the optical treatment unit as of FIG. 2 schematically.

[0096] FIG. 6 illustrates a possible configuration of the optical functional tracking unit as of FIG. 4 schematically.

EXAMPLES OF EMBODIMENTS OF THE PRESENT INVENTION

[0097] Concerning FIG. 1a, an example of a confocal scanning laser ophthalmoscope 1 according to the invention is illustrated. The confocal scanning laser ophthalmoscope 1 is named apparatus in the following.

[0098] The apparatus can be combined with or integrated into a fundus camera or another optical device typically used by physicians. However, the apparatus can also be configured as an independent, standalone device.

[0099] The apparatus 1 consists, in this example, of an optical treatment and functional tracking module 3, an optical power module 5, and a control module 7. The modules 3, 5, 7 can be placed in one common housing.

[0100] A front lens (not illustrated) of the apparatus 1 is directed towards an eye 100, whereby the optical treatment and functional tracking module 3 emit a treatment beam 91 and a functional excitation beam 92 towards the eye 100. The said lights pass through the front lens before entering the eye 100.

[0101] A portion of the functional excitation beam 92 is reflected by the retina comprised in the eye 100 and enters through the front lens of the optical treatment and functional tracking module 3 as reflected light by the retina 93. The same applies to the treatment beam 91. Some portions of the treatment beam 91 may be reflected by the by the retina 93 and may enter the of the optical treatment and functional tracking module 3 as reflected light.

[0102] The optical treatment and functional tracking module 3 determines the spectrum of the reflected light by the retina 93 and the apparatus adapts some parameters, such as the pulse width of the light pulse comprised in the treatment beam 91 in response to the detection of a change in the spectrum of the reflected light by the retina 93.

[0103] The optical power module 5 supplies the optical treatment and functional tracking module 3 with the necessary optical power to emit a treatment beam 91 to the eye 100. The optical power is transmitted from the optical power module 5 to the optical treatment and functional tracking module 3 through an optical power and communication bus 11, whereby the said bus 11 also is used for communication of operational and/or control commands parameters between the optical power module 5 and the optical treatment and functional tracking module 3.

[0104] The optical portion of the optical power and communication bus 11 is configured with an optical fiber that is suitable to conduct light without high losses.

[0105] The operation of the optical power module 5, the optical treatment and functional tracking module 3 is controlled by the control module 7. The control module 7 is communicatively connected to the said modules through communication buses 12, 13.

[0106] The control module 7 is also destined to adapt and control the emission of the treatment beam 91 in response to a change in the spectrum detected by the optical treatment and functional tracking module 3. The control module 7 directly influences the light generation in the optical power module 5.

[0107] The control module 7 can be perceived as an overarching control device, configurated to control the operation of the apparatus 1 and providing (technical) diagnostic features for all other modules 3, 5.

[0108] The apparatus 1 further comprises a human-machine interface (HMI) 6 in form of a touchscreen, touch pad and/or a keyboard. The HMI 6 is used, for instance, by an ophthalmologist to enter treatment parameters, such as treatment objectives, pupil diameters, etc.

[0109] A footswitch, as a part of the HMI 6 is used by the physician to activate the emission of the treatment beam 91 and the functional excitation beam 92.

[0110] The functionality of the modules 3, 5, 7 as herein disclosed before, is exemplified. Some of the functionalities can be combined in one module or the apparatus 1 may comprise further modules to deconcentrate the functionality further.

[0111] In a highly simplified description of the present apparatus 1 an optical-electrical feedback control is provided by the modules, in which the optical treatment unit 31, in combination with the retinal cells correspond to the system to be controlled, in which the optical functional tracking unit 32 corresponds to the sensor and in which the control module 7 corresponds to the controller.

[0112] FIG. 1b illustrates an example of the tissue stimulation by the treatment beam and the corresponding reaction of the cells.

[0113] The treatment beam 91 and the functional excitation beam 92 are emitted in the direction of the eye 100. They enter the pupil of the eye 100 as the envelope 110 does not cover the cornea. The beams 91, 92 penetrate the eyeball and impinge on the retina 120. Portions of the beam/light of the functional excitation beam 92 are reflected by the retina 120 and reverberate in the direction of the pupil as reflected light 93. Portions of the treatment beam 91 may also be reflected by the retina 120.

[0114] The reflected light 93 leaves the eyeball and enters the apparatus 1 as shown in FIG. 1a.

[0115] The treatment beam 91 causes a tissue stimulation 130 in the related cells. Different cells or layers of the retina may be targeted by the treatment beam 91. In reverse, the effect of the tissue stimulation 130 causes a change in the spectrum of the reflected light 93.

[0116] It needs to be noted that depending on the stimulation (intensity, duration, etc.) the spectrum may change differently. For example, a stimulation with high intensity may cause a redshift in the spectrum of the reflected light 93.

[0117] FIG. 2 illustrates an example of an optical treatment and functional tracking module 3 of the apparatus according to the invention.

[0118] The optical treatment and functional tracking module 3 comprises a front lens module 9, an optical treatment unit 31, optical functional tracking unit 32, and a laser beam exit module 33.

[0119] The optical treatment and functional tracking module 3 further comprises input and output ports arranged so the module can be connected to the communication bus 13 and the optical power and communication bus 11.

[0120] The optical treatment unit 31 also comprises a plurality of optical elements, such as mirrors, lens arrays and other elements for filtering light. The said optical elements are used to guide, divert, focus and/or concentrate in combination with the front lens module 9 treatment beam 91 on selected areas of the retina.

[0121] The phrase in combination with means in this respect that the optical path provided for the treatment beam 91 is a combination of the optical elements comprised in the optical treatment unit 31 and the front lens module 9.

[0122] The light that is focused or concentrated by the optical treatment unit 31 is provided by the laser beam exit module 33 and originates from the optical power module 5. The light emanating from the optical power module 5 is provided over the optical power and communication bus 11.

[0123] The optical functional tracking unit 32 also comprises a plurality of optical elements, such as mirrors, lens arrays and additional elements for filtering light. In addition, the optical functional tracking unit 32 includes a light source capable of providing light within a specific spectrum.

[0124] The light source used in this example for the optical functional tracking unit 32 is a near-infrared light source with wavelengths ranging between 750 nm and 980 nm.

[0125] The near-infrared light source emits the light passing through the plurality of optical elements and the front lens module 9 as functional excitation beam 92 into the direction of the eye. The retina of the eye reflects the functional excitation beam 92, whereby the light returns in the form of reflected light by the retina 93 and passes through the front lens module 9 and the plurality of optical elements comprised in the optical functional tracking unit 32.

[0126] A detector in the form of an Avalanche-Photodiode-Array (APA) and an optical grating placed in front of the sensor surface of the APA. The detector is used to extract spectral data from the reflected light by the retina and detects changes in the spectrum of the reflected light by the retina 93, while the treatment beam 91 is applied to the retina.

[0127] The treatment beam 91, the functional excitation beam 92 and the reflected light by the retina 93 share the same optical path as they pass at least through the front lens module 9 altogether.

[0128] FIG. 3 illustrates an example of a total therapeutic dose 90 in the form of a repetition of treatment light pulses 911.

[0129] Light is emitted via the front lens module to the eye in the form of such a therapeutic dose 90. One therapeutic dose 90 applied to the retina can comprise in this example a plurality of periodic treatment light pulses 911. The total therapeutic dose 90 is delivered to the targeted tissues within a certain period of time, the total exposure duration T.sub.tot.

[0130] The treatment beam 91 delivers the total therapeutic dose 90 to the targeted tissues with a pulsed protocol. The total exposure duration T tot is split into multiple pulse periods 1/f in which a treatment light pulse 911 is emitted. As indicated on the abscissa of the graph, the treatment light pulse 911 in each pulse period 1/f has a specific width corresponding to the pulse width .

[0131] Typical values used in this example are a pulse period 1/f of 400 s, a pulse width T of 100 s, which correspond to a duty cycle of 25%, and an exposure duration T tot of 400 ms. These values result in the transmission of 1000 pulses for treatment of a selected area on the retina.

[0132] Each light pulse is characterised by a peak power amplitude P.sub.0, as indicated on the ordinate of the graph. In this example accounts for the peak power amplitude P.sub.0 to 40 W. The peak power amplitude P.sub.0 may correspond to the radiant flux .sub.e emitted by the apparatus 1.

[0133] The total therapeutic dose 90, expressed in terms of, irradiance x, total exposure duration T.sub.tot, or fluence applied to the retina can be controlled by the amplitude of the radiated pulse P.sub.0, the variation of total exposure duration T.sub.tot, and/or the pulse width .

[0134] As indicated before, the total therapeutic dose 90 is adjusted in response to detecting a change in the spectrum of the reflected light by the retina.

[0135] Therefore, the values as provided before are only applicable for a stable operational point and might be subject to change during the application of the therapeutic dose 90.

[0136] Regarding FIG. 4, an example of an optical power module 5 of the apparatus according to the invention is illustrated.

[0137] The optical power module 5 comprises a laser interface module 51, a laser control module 52 and a laser beam output module 53.

[0138] The optical power module 5 also comprises input and output ports such that the said module can be connected to the communication bus 12, and to the optical power and communication bus 11.

[0139] The laser interface module 51 comprises a power supply unit for supplying the laser control module 52 with electrical energy through the communication and electrical power supply bus 55.

[0140] The laser interface module 51 comprises a switching unit configured to interrupt or permit the supply of electrical energy to the laser control module 52. The switching unit is coupled to the footswitch of the HMI. The flow of electrical energy to the laser control module 52 is permitted if a physician activates the footswitch.

[0141] The laser control module 52 includes a light source in the form of a laser diode. The laser diode is configured to emit light with a specific wavelength, preferably with a wavelength of 810 nm or 830 nm. Due to tolerances in the manufacturing and/or during operation of the laser diode the wavelength might have a tolerance of +/5 nm (e.g. full width at half maximum).

[0142] The laser diode is supplied with electrical energy provided by the laser interface module 51. The electrical energy is varied by a control device in the laser control module 52. The said control device controls or sets the energy that is supplied to the laser diode in a way that a pulse pattern is generated, as discussed in regards to FIG. 3 hereinbefore.

[0143] The said control device can also be connected through the communication bus 13 to the control module 7 of FIG. 1a. The control device receives control commands or settings from the control module 7 of FIG. 1a to set the pulse pattern and finally the therapeutic dose 90 in response to the detection of a change in the spectrum, which was detected by the optical functional tracking unit 32 of FIG. 2 and corresponding to a treatment objective that a physician set via the HMI of FIG. 1a.

[0144] However, this might not be the only possibility. The said control device might also be directly connected to the optical functional tracking unit 32 of FIG. 2, and receive commands to adapt the treatment beam 91 directly in response to detecting a change in the spectrum.

[0145] This may reduce the latency of the communication buses 12, 13 and improve the reactivity of adapting the total therapeutic dose 90.

[0146] The light which is emitted by the laser diode is transmitted to the laser beam output module 53. The laser beam output module 53 connects the light optically with the optical power and communication bus 11. The optical fiber comprised in the optical power and communication bus 11 conducts the light to the laser light input module of FIG. 2.

[0147] FIG. 5 shows an example configuration of the optical treatment unit as of FIG. 2.

[0148] In the first optical path, a treatment light source 311 generates with the use of a laser diode a treatment beam 91, having a wavelength of 830 nm.

[0149] The treatment beam 91 is redirected by an optical mirror 320 and enters the tissue layer selection 313 lens array. The said lens array 313 comprises multiple lenses, whereby at least one lens can vary its position to change the focal point (focus length) corresponding to the tissue layer which needs to be targeted.

[0150] The treatment beam 91 subsequently enters a second lens array 315 to further concentrate the treatment beam 91. Finally the treatment beam 91 arrives at the dichroic mirror 318 where it is redirected toward the front lens module 9.

[0151] The treatment light source 311, the optical mirror 312, and the lens arrays 313, 315 can be components of the optical treatment unit 31 as illustrated in FIG. 2.

[0152] The treatment beam 91 exits the front lens module 9 and is emitted into the direction of the eye 100.

[0153] In a second optical path, the optical functional tracking module 32 is energised at the same time, as the treatment light source 311 and thus emits a functional excitation beam 92 into the direction of the dichroic mirror 318. The dichroic mirror 318 directs the functional excitation beam 92 towards the front lens module 9 and exits the front lens module in the direction of the eye 100.

[0154] Portions of the functional excitation beam 92 are reflected by the retina comprised in the eye 100 and enter as reflected light by the retina 93 the front lens module 9 into the direction of the dichroic mirror 318. The reflected light by the retina 93 travels through the dichroic mirror 318 and uses the same optical path as the functional excitation beam 92.

[0155] The reflected light by the retina 93 enters the optical functional tracking unit 32, where the light i.a. is decomposed into its spectral components. The remaining functionalities are in line as explained in connection with FIG. 2.

[0156] The third optical path thus ranges between the front lens module 9 and the eye 100 and is shared by the treatment and functional excitation beam 91, 92 and the reflected light from the retina 93.

[0157] It can be noticed that the dichroic mirror 318 functions as an optical collector and deflector point, where multiple optical paths meet.

[0158] FIG. 6 illustrates a possible configuration of the optical functional tracking unit as of FIG. 4.

[0159] The treatment beam 91 in the first optical path is generated by the optical treatment unit 31. The optical treatment unit 31 can comprise the components as illustrated in FIG. 5. The treatment beam 91 is redirected at the dichroic mirror 318 into the direction of the front lens module 9. The treatment beam 91 exits the front lens module 9 and is emitted into the direction of the eye 100.

[0160] In a second optical path, light is generated by the broadband near infrared (NIR) light source and concentrated and/or filtered by the excitation pinhole 324 to emit the functional excitation beam 92.

[0161] The functional excitation beam 92 passes through the excitation/emission cube 323 and travels towards the tomogram selection optics 322. The tomogram selection optics 322 comprises multiple lenses, whereby at least one lens can vary its position to change the focal point (focus length) on the retina. The focal point on the retina for the functional excitation beam 92 can be the same focal point as for the treatment beam 91.

[0162] Upon leaving the tomogram selection optics 322, the functional excitation beam 92 is redirected by the 2-D scanning system 321 comprising a movable mirror. The position of the excitation beam 92 on the retina can be variably selected by changing the position of the mirror. The position or selected area on the retina of the functional excitation beam 92 and the treatment beam 91 can be exactly the same.

[0163] It is also possible that the functional excitation beam 92 targets a different position or area, which can be useful to monitor the tissue interaction of the treatment beam 91 in the environmental tissue or different layer of the retina.

[0164] The excitation beam 92 travels from the 2-D scanning system 321 to the dichroic mirror 318, whereby the dichroic mirror 318 directs the functional excitation beam 92 towards the front lens module 9 and exits the front lens module into the direction of the eye 100.

[0165] The reflected light by the retina 93 travels back through the front lens module 9, the dichroic mirror 318, the 2-D scanning system 321, the tomogram selection optics 322 and finally enters the excitation/emission cube 323, where it is redirection towards the notch filter and emission pinhole 326.

[0166] The notch filter and emission pinhole 326 can be used for stray light exclusion.

[0167] An optical dispersive grating 327 is placed in front of the line detector 328. The optical dispersive grating 327 is used to split the reflected light by the retina 93 into different wavelengths, whereby the line detector 328 captures the light level of the different wavelengths.

[0168] In conclusion, the apparatus can detect a change in the spectrum of the reflected light by the retina 93, preferably at selectable positions or areas on the retina, thanks to the 2-D scanning system.

[0169] The arrows as illustrated in all figures indicate in which direction the light travels and/or the beam is emitted or reflected.

[0170] All example embodiments present a limited selection of possible configurations of the apparatus/confocal scanning laser ophthalmoscope. However, different other configurations can solve the technical problem as set out in the initial section of this disclosure.

REFERENCE SIGNS

[0171] 1 confocal scanning laser ophthalmoscope, apparatus [0172] 3 optical treatment and functional tracking module [0173] 5 optical power module [0174] 6 human machine interface (HMI) [0175] 7 control module [0176] 9 front lens module [0177] 11 optical power and communication bus [0178] 12, 13 communication bus [0179] 31 optical treatment unit [0180] 32 optical functional tracking unit [0181] 33 laser beam exit module [0182] 51 laser interface module [0183] 52 laser control module [0184] 53 laser beam output module [0185] 55 communication or control bus [0186] 56 laser light bus [0187] 90 (total) therapeutic doseintegral on light pulse envelope dose of light [0188] 91 treatment beam, light beam [0189] 92 functional excitation beam [0190] 93 reflected light by the retina while stimulated by excitation beam [0191] 100 eye [0192] 110 envelope [0193] 120 retina [0194] 130 tissue stimulation [0195] 311 treatment light source [0196] 312 optical mirror [0197] 313 tissue layer selectiontreatment [0198] 315 relay lenses [0199] 318 dichroic mirror [0200] 321 2-D scanning system [0201] 322 tomogram selection optics [0202] 323 excitation/emission cube [0203] 324 excitation pinhole [0204] 325 broadband NIR light source [0205] 326 notch filter (stray light exclusion) and emission pinhole [0206] 327 optical dispersive grating [0207] 328 line detector [0208] 911 treatment light pulse [0209] P.sub.0 peak power amplitude of the radiated pulse [0210] 1/f pulse period [0211] T.sub.tot exposure duration [0212] .sub.e radiant flux/power [0213] pulse width.