Full-field strain mapping for characterization of structure-related variation in corneal biomechanical properties using digital image correlation (DIC) technology

Characterization of structure-related variation in corneal biomechanical properties is important for the design of corneal implants with a controllable degradation. In the current study, we conducted an in-vitro inflation experiment on contact and structural-damaged porcine corneas and mapped the strain distribution during using digital image correlation (DIC) algorithm. The inflation experiment was performed with a pressure loading device, a steady-state pressure transducer and DIC system. Corneal samples with uniformly-distributed paint particles were fixed on the loading device, and then were subjected increasing pressure load through injection with a constant velocity (0.134 ​ml/min). Three-dimensional (3D) DIC algorithm was performed to present a map of the full-field strain distribution on the corneal surface. The results showed a significant difference in the strain distribution between the intact and damaged corneas. The time-strain history also exhibited differently when the two types of cornea samples were subjected to inflation. It indicated that the DIC technology is validated to characterize structure-related variation in corneal biomechanical properties.