Background To comprehensively evaluate the agreement of component corneal aberrations from the newly updated wavefront analysis software of a swept-source optical coherence tomographer(SS-OcT)and a referential Placido...Background To comprehensively evaluate the agreement of component corneal aberrations from the newly updated wavefront analysis software of a swept-source optical coherence tomographer(SS-OcT)and a referential Placido-topography combined OcT device in elderly cataract patients.Methods Retrospective study including 103 eyes from 103 elderly patients scheduled for cataract surgery that were measured on the same day with a SS-OcT(Heidelberg Engineering,Germany)device and a Placido-topography combined OCT device(CsO,Italy).Anterior,total,and posterior corneal wavefront aberrations were evaluated for their mean differences and limits of agreement(LoA)via Bland-Altman plots.Vector analysis was additionally employed to compare corneal astigmatism measurements in dioptric vector space.Results Mean differences of all corneal aberrometric parameters did not exceed O.05 um.Total corneal aberrations were not significantly different from 0 except for vertical coma(-0.04μm;P=0.003),spherical aberration(-0.01μm,P<0.001),and root mean square(RMS)higher-order aberration(HOA)(0.03μm,P=0.04).The 95%LoA for total corneal aberration parameters between both devices were-0.46 to 0.42μm for horizontal astigmatism,-0.37 to 0.41μm for oblique astigmatism,-0.19 to 0.17μm for oblique trefoil,-0.33 to 0.25μm for vertical coma,-0.20 to 0.22μm for horizontal coma,-0.22 to 0.20 um for horizontal trefoil,-0.11 to 0.08μm for spherical aberration,and-0.22 to 0.28 um for RMs HOA.Vector analysis revealed no statistically significant mean differences for anterior,total,and posterior corneal astigmatism in dioptric vector space.Conclusion In eyes undergoing cataract surgery with a regular elderly cornea,corneal wavefront analysis from the SS-OcT device showed functional equivalency to the reference device.Nevertheless,clinically relevant higher-order aberration parameters should be interpreted with caution for surgical decision-making.展开更多
Photonic integrated circuits(PICs)represent a promising technology for the muchneeded medical devices of today.Their primary advantage lies in their ability to integrate multiple functions onto a single chip,thereby r...Photonic integrated circuits(PICs)represent a promising technology for the muchneeded medical devices of today.Their primary advantage lies in their ability to integrate multiple functions onto a single chip,thereby reducing the complexity,size,maintenance requirements,and costs.When applied to optical coherence tomography(OCT),the leading tool for state-of-the-art ophthalmic diagnosis,PICs have the potential to increase accessibility,especially in scenarios,where size,weight,or costs are limiting factors.In this paper,we present a PIC-based CMOS-compatible spectrometer for spectral domain OCT with an unprecedented level of integration.To achieve this,we co-integrated a 512-channel arrayed waveguide grating with electronics.We successfully addressed the challenge of establishing a connection from the optical waveguides to the photodiodes monolithically co-integrated on the chip with minimal losses achieving a coupling efficiency of 70%.With this fully integrated PIC-based spectrometer interfaced to a spectral domain OCT system,we reached a sensitivity of 92dB at an imaging speed of 55kHz,with a 6dB signal roll-off occurring at 2mm.We successfully applied this innovative technology to obtain 3D in vivo tomograms of zebrafish larvae and human skin.This ground-breaking fully integrated spectrometer represents a significant step towards a miniaturised,cost-effective,and maintenance-free OCT system.展开更多
In this work,we present a significant step toward in vivo ophthalmic optical coherence tomography and angiography on a photonic integrated chip.The diffraction gratings used in spectral-domain optical coherence tomogr...In this work,we present a significant step toward in vivo ophthalmic optical coherence tomography and angiography on a photonic integrated chip.The diffraction gratings used in spectral-domain optical coherence tomography can be replaced by photonic integrated circuits comprising an arrayed waveguide grating.Two arrayed waveguide grating designs with 256 channels were tested,which enabled the first chip-based optical coherence tomography and angiography in vivo three-dimensional human retinal measurements.Design 1 supports a bandwidth of 22nm,with which a sensitivity of up to 91 dB(830μW) and an axial resolution of 10.7 pm was measured.Design 2 supports a bandwidth of 48 nm,with which a sensitivity of 90 dB(480μW) and an axial resolution of 6.5μm was measured.The silicon nitride-based integrated optical waveguides were fabricated with a fully CMOS-compatible process,which allows their monolithic co-integration on top of an optoelectronic silicon chip.As a benchmark for chip-based optical coherence tomography,tomograms generated by a commercially available clinical spectral-domain optical coherence tomography system were compared to those acquired with on-chip gratings.The similarities in the tomograms demonstrate the significant clinical potential for further integration of optical coherence tomography on a chip system.展开更多
文摘Background To comprehensively evaluate the agreement of component corneal aberrations from the newly updated wavefront analysis software of a swept-source optical coherence tomographer(SS-OcT)and a referential Placido-topography combined OcT device in elderly cataract patients.Methods Retrospective study including 103 eyes from 103 elderly patients scheduled for cataract surgery that were measured on the same day with a SS-OcT(Heidelberg Engineering,Germany)device and a Placido-topography combined OCT device(CsO,Italy).Anterior,total,and posterior corneal wavefront aberrations were evaluated for their mean differences and limits of agreement(LoA)via Bland-Altman plots.Vector analysis was additionally employed to compare corneal astigmatism measurements in dioptric vector space.Results Mean differences of all corneal aberrometric parameters did not exceed O.05 um.Total corneal aberrations were not significantly different from 0 except for vertical coma(-0.04μm;P=0.003),spherical aberration(-0.01μm,P<0.001),and root mean square(RMS)higher-order aberration(HOA)(0.03μm,P=0.04).The 95%LoA for total corneal aberration parameters between both devices were-0.46 to 0.42μm for horizontal astigmatism,-0.37 to 0.41μm for oblique astigmatism,-0.19 to 0.17μm for oblique trefoil,-0.33 to 0.25μm for vertical coma,-0.20 to 0.22μm for horizontal coma,-0.22 to 0.20 um for horizontal trefoil,-0.11 to 0.08μm for spherical aberration,and-0.22 to 0.28 um for RMs HOA.Vector analysis revealed no statistically significant mean differences for anterior,total,and posterior corneal astigmatism in dioptric vector space.Conclusion In eyes undergoing cataract surgery with a regular elderly cornea,corneal wavefront analysis from the SS-OcT device showed functional equivalency to the reference device.Nevertheless,clinically relevant higher-order aberration parameters should be interpreted with caution for surgical decision-making.
基金carried out in the framework of the project COHESION,No.848588funded by the Austrian Research Promotion Agency(FFG)support for the research of this work from funding from the European Union’s Horizon 2020 research and innovation program HandheldOCT(H2020,ICT 871312).
文摘Photonic integrated circuits(PICs)represent a promising technology for the muchneeded medical devices of today.Their primary advantage lies in their ability to integrate multiple functions onto a single chip,thereby reducing the complexity,size,maintenance requirements,and costs.When applied to optical coherence tomography(OCT),the leading tool for state-of-the-art ophthalmic diagnosis,PICs have the potential to increase accessibility,especially in scenarios,where size,weight,or costs are limiting factors.In this paper,we present a PIC-based CMOS-compatible spectrometer for spectral domain OCT with an unprecedented level of integration.To achieve this,we co-integrated a 512-channel arrayed waveguide grating with electronics.We successfully addressed the challenge of establishing a connection from the optical waveguides to the photodiodes monolithically co-integrated on the chip with minimal losses achieving a coupling efficiency of 70%.With this fully integrated PIC-based spectrometer interfaced to a spectral domain OCT system,we reached a sensitivity of 92dB at an imaging speed of 55kHz,with a 6dB signal roll-off occurring at 2mm.We successfully applied this innovative technology to obtain 3D in vivo tomograms of zebrafish larvae and human skin.This ground-breaking fully integrated spectrometer represents a significant step towards a miniaturised,cost-effective,and maintenance-free OCT system.
基金The authors thank Rene Werkmeister for data acquisition and permission to use the data from the commercial benchmark system and EXALOS AG for the booster amplifier.E.A.R.greatly acknowledges fruitful discussions with Fabian Placzek.This work was carried out in the framework of project COHESION,No.848588,funded by the Austrian Research Promotion Agency(FFG).This research has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No.688173(OCTCHIP).DJ.H.gratefully acknowledges financial support from the European Research Council(ERC)(No.640396 OPTIMALZ).
文摘In this work,we present a significant step toward in vivo ophthalmic optical coherence tomography and angiography on a photonic integrated chip.The diffraction gratings used in spectral-domain optical coherence tomography can be replaced by photonic integrated circuits comprising an arrayed waveguide grating.Two arrayed waveguide grating designs with 256 channels were tested,which enabled the first chip-based optical coherence tomography and angiography in vivo three-dimensional human retinal measurements.Design 1 supports a bandwidth of 22nm,with which a sensitivity of up to 91 dB(830μW) and an axial resolution of 10.7 pm was measured.Design 2 supports a bandwidth of 48 nm,with which a sensitivity of 90 dB(480μW) and an axial resolution of 6.5μm was measured.The silicon nitride-based integrated optical waveguides were fabricated with a fully CMOS-compatible process,which allows their monolithic co-integration on top of an optoelectronic silicon chip.As a benchmark for chip-based optical coherence tomography,tomograms generated by a commercially available clinical spectral-domain optical coherence tomography system were compared to those acquired with on-chip gratings.The similarities in the tomograms demonstrate the significant clinical potential for further integration of optical coherence tomography on a chip system.
