Development And Application Of Optical Coherence Elastography For A Corneal Biomechanical Imaging System

Purpose: To develop an optically coherent elastography system with acoustic radiation force for corneal biomechanical property detection;to carry out 2D and 3D structural and elastic reconstruction of the cornea,and to discuss the complex relationship between corneal disease and elastic modulus.Methods: The sinusoidal wave signal generated by the function generator is amplified by the amplifier to drive the ultrasonic transducer to generate acoustic radiation force to excite the tissue to produce vibration;the optical coherence chromatography technique is used to detect the shear wave propagation associated with the vibration,and the phase-resolved Doppler algorithm or Doppler variance algorithm is developed simultaneously to detect the shear wave propagation inside the sample,and the direct relationship between the shear wave velocity and the shear modulus is calculated from the The elastic modulus of the sample.In order to verify the feasibility of the system,a series of agar mimics with determined hardness were synthesized,and the system was validated by comparing the difference between the experimentally obtained elastic modulus and the intrinsic elastic modulus using the developed optical coherence elastography system for elastography.In addition,elastography of isolated human corneas and cone corneas was carried out.Two-dimensional OCT structural images of the human cornea,elastic wave propagation images,and Young’s modulus at different intraocular pressures were obtained.Results: An optical coherent elastography system based on acoustic radiation force was successfully constructed with axial resolution,displacement sensitivity,imaging depth,scan range,scan frequency,and signal-to-noise ratio of 2.6 μm,0.3 nm,3.5mm,6 × 6 mm,50 k Hz,and 97 d B,respectively.elastic wave velocity in an agar mimic sample of known hardness was measured using the system with a value of10.74 m /The Young’s modulus increased from 26.13 k Pa to 653.67 k Pa as the IOP increased from 5 mm Hg to 55 mm Hg.The Young’s modulus in the conical region of the conical cornea,including the transition region and the peripheral region,was 49.1k Pa,55.4 k Pa,and 60.3 k Pa.Conclusions:The results of this study show that the optical coherent elastography system with acoustic radiation force has the potential for clinical corneal biomechanical property detection,which can achieve non-destructive,non-contact,high-resolution quantitative quantification of biological tissue elastic modulus and provide new dimensions of diagnostic information for the pathogenesis,diagnosis,treatment and prevention of corneal refractive surgery,cone cornea,myopia,glaucoma.