Microscale assessment of corneal viscoelastic properties under physiological pressures.

In this study the micromechanical properties of pressurised porcine corneas were determined using oscillatory nanoindentation coupled with a custom inflation method. Inflation was conducted in phosphate buffered saline (PBS) and tissue culture (TC) solutions. The shear storage modulus (G') and shear loss modulus (G") was determined for corneas inflated corneas with PBS and TC. Central corneal thickness (CCT) was monitored during the inflation (0-60 mmHg). Elastic modulus (E) was also calculated and quantitatively mapped for corneas. The results showed that G' at 15 mmHg was 86.18 ± 16 kPa and 88.86 + 13.54 kPa inflated by PBS and TC respectively. These values increased 3.2 times in an approximate linear relationship to 60 mmHg. G″ at 15 mmHg was 12.5 ± 2.5 kPa and 13.54 + 1.9 kPa inflated by PBS and TC respectively. G″ increased 1.9 times in an approximate linear relationship to 60 mmHg. No significant change was noticed in viscoelastic properties of corneas inflated by TC for 4 h whereas 4 h of hydration on PBS affected the mechanical properties. The central corneal region was found to be stiffer than in peripheral region. Mapping of elasticity revealed a symmetrical distribution of properties that varied with inflation. Our method has potential for measurement of viscoelastic properties of corneas in conditions where there have been localised changes in mechanical properties such as keratoconus. PMID: 31376792 [PubMed - as supplied by publis...
Source: Journal of the Mechanical Behavior of Biomedical Materials - Category: Materials Science Authors: Tags: J Mech Behav Biomed Mater Source Type: research