Evaluation of Trends from Highly Nonlinear Solitary Wave Transducer in Soft Materials

Highly nonlinear solitary waves (HNSWs) are frequently used to inspect the properties of a material without causing irreversible damage to the structure. Nondestructive evaluation is especially useful in avoiding damage to soft materials with a Young's modulus less than 1MPa. Nondestructive testing would provide insight into biological materials, such as corneas, by monitoring overall eye health and intraocular pressure (IOP). The research in this paper proposes a new application for HNSWs: predicting changes in a cornea correlating to IOP. IOP monitoring is the target application for this research because it is the best methodology for tracking eye disease progression. The HNSWs used for assessment were collected from Polydimethylsiloxane (PDMS) cornea models pressurized from 12mmHg to 26mmHg with 1mmHg increments. Time, amplitude, and frequency content are extracted from each HNSW and compared to estimate the IOP of corneas ranging in thickness from 912μm to 1238μm. To decrease the variability in these three features, a fused variable which reflects the best performing feature in every sample is explored to perform more accurate IOP predictions.