In Vivo Biomechanical Mapping of Normal and Keratoconus Corneas

Corneal mechanical strength is critical to withstanding intraocular pressure and maintaining normal shape1,2. In keratoconus, the mechanical stability is compromised3, and this may lead to progressive morphological changes. Therefore, a noninvasive technique capable of accurately measuring the mechanical properties of the cornea may help understand the mechanism of keratoconus development and improve detection and intervention in keratoconus. We have previously developed Brillouin microscopy based on light scattering from inherent acoustic waves in tissues4 and shown that this technique can provide quantitative estimates of local longitudinal modulus5, which correlate to the Young's/shear moduli of the cornea2,6. Using a clinically viable instrument, for the first time to our knowledge, here we mapped the elastic modulus of normal and keratoconus patients in vivo. We found distinctive biomechanical features that differentiate normal and keratoconic corneas and, therefore, have potential to serve as diagnostic metrics for keratoconus.