Longitudinal assessment of the effect of alkali burns on corneal biomechanical properties using optical coherence elastography

Abstract

Eye injury due to alkali burn is a severe ocular trauma that can profoundly affect corneal structure and function, including its biomechanical properties. Here, we assess the changes in the mechanical behavior of mouse corneas in response to alkali‐induced injury by conducting longitudinal measurements using optical coherence elastography (OCE). A non‐contact air‐coupled ultrasound transducer was used to induce elastic waves in control and alkali‐injured mouse corneas in vivo, which were imaged with phase‐sensitive optical coherence tomography. Corneal mechanical properties were estimated using a modified Rayleigh–Lamb wave model, and results show that Young's modulus of alkali‐burned corneas were significantly greater than that of their healthy counterparts on days 7 (p = 0.029) and 14 (p = 0.026) after injury. These findings, together with the changes in the shear viscosity coefficient postburn, indicate that the mechanical properties of the alkali‐burned cornea are significantly modulated during the wound healing process.

Optical coherence elastography measures the biomechanical properties of the ex vivo porcine cornea after LASIK

“…However, the study sheds no light on the mechanical alterations in the tissue during and after the healing process. Nevertheless, OCE may be able to evaluate changes in mechanical properties throughout the wound healing process 31 and is a direction of our future work. In this study, the corneal flap was laid flat against the residual stromal bed, and no external method for adherence was utilized.…”

Multifocal acoustic radiation force-based reverberant optical coherence elastography for evaluation of ocular globe biomechanical properties

“…The spot size, defined as the full width half maximum of the normalized pressure intensity at the focal plane, was determined to be 1.13 mm. The induced reverberant shear wave field was detected using a PhS-OCT system characterized by displacement stability, axial resolution in air, and transverse resolution of 0.28 nm, ∼9 μm, and ∼8 μm, respectively 20 . The OCT system was operated at an A-line rate of 25 kHz.…”

“…Similarly, a 2D spatial bandpass filter was applied to remove unwanted motion noise. The wavenumber filter was designed by setting the cutoff frequencies based on previously established ranges of shear wave speed in soft tissues, such as the mouse eye, which typically falls between 0.4 and 9.5 m/s 20 , 23 . Then, the lower (kl) and upper (ku) limits of the wavenumber filter were determined using the relation [kl,ku]=[2πf/vu,2πf/vl], where f=3 kHz was the excitation frequency and vl=0.4 m/s and vu=9.5 m/s were the assumed speed limits.…”

Optical coherence elastography and its applications for the biomechanical characterization of tissues

“…OCE can evaluate the elasticity of biological tissues, such as the cornea [58][59][60][61][62][63][64][65], the lens [66][67][68], the retina [69], the artery [30], the tumor [15,[70][71][72][73][74][75][76][77], the brain [78], the skin [28], and some other tissues [79][80][81][82], providing new evidence for clinical research. This section presents a few recent applications in ophthalmology, endoscopy, and oncology.…”

“…Ocular injury caused by alkali burns can profoundly change the structure and function of the cornea. Mekonnen et al measured corneal biomechanical properties of alkali-burned rat corneas using dynamic OCE [58]. After the air-coupled ultrasound transducer induced an elastic wave in the cornea, the viscoelastic properties of the cornea were analyzed by a modified Rayleigh-Lambda wave model.…”