Ultrafast line-field holographic elastography with single excitation for corneal biomechanical characterization.

Elastography has become an essential tool for assessing tissue biomechanics, in particular for the diagnosis and treatment of keratoconus. For in vivo measurements, high-speed imaging and reduced stimulation are crucial. In this study, we introduce a line-field holographic elastography (LF-HE), which employs line-focus illumination and parallel acquisition to achieve ultra-fast measurement in 14 ms with single excitation. A novel data processing method combining the short time Fourier transform, the phase-resolved color Doppler and full width at half maximum algorithms is proposed to extract the local biomechanical property. Agar phantoms with various concentrations were measured to valid the LF-HE system. The changes of stiffness of in situ porcine corneas treated by riboflavin/UV-A collagen cross-linking (UV-CXL) were also detected in a lateral range of 4.4 mm by modifying the light path of sample arm. This research demonstrated the significant potential of LF-HE for application in ophthalmology clinics.