Singh et al. (2017). Journal of Biomedical Optics. doi: 10.1117/1.jbo.22.9.091504
…region represents the masked area during the partial CXL treatment. Figures are not to scale. CXL was induced on all but a central 2 mm diameter circle of fresh mature rabbit corneas ( n = 4 , Pel-Freez Biologicals, Arkansas) to induce a spatial variation of stiffness as depicted in Fig. 1(c) . Additional OCE measurements were made on a separate sample before and after traditional CXL treatment. Apart from…
Abstract
UV-induced collagen cross-linking is a promising treatment for keratoconus that stiffens corneal tissue and prevents further degeneration. Since keratoconus is generally localized, the efficacy of collagen cross-linking (CXL) treatments could be improved by stiffening only the weakened parts of the cornea. Here, we demonstrate that optical coherence elastography (OCE) can spatially resolve transverse variations in corneal stiffness. A short duration ( ? 1 ?? ms ) focused air-pulse induced low amplitude ( ? 10 ?? ? m ) deformations in the samples that were detected using a phase-stabilized optical coherence tomography system. A two-dimensional map of material stiffness was generated by measuring the damped natural frequency (DNF) of the air-pulse induced response at various transverse locations of a heterogeneous phantom mimicking a customized CXL treatment. After validation on the phantoms, similar OCE measurements were made on spatially selective CXL-treated in situ rabbit corneas. The results showed that this technique was able to clearly distinguish the untreated and CXL-treated regions of the cornea, where CXL increased the DNF of the cornea by ? 51 % . Due to the noncontact nature and minimal excitation force, this technique may be valuable for in vivo assessments of corneal biomechanical properties.