Table 1.
Regional radial, tangential, and shear strains in normal and keratoconic corneas when IOP was increased from 5 to 30 mmHg.
|
Radial |
Tangential |
Shear |
||||||
|---|---|---|---|---|---|---|---|---|
| Eye | Age | Paracentral | Central | Paracentral | Central | Paracentral | Central | |
| Experimental | Normal (n=11) | 63 | −2.56±2.42% | −1.98±1.02% | 1.82±1.47% | 0.25±1.16% | 2.75±1.11% | 3.15±2.14% |
| KC1 | 49 | −9.17% | −4.93% | 1.98% | −1.47% | 2.78% | 3.83% | |
| KC2 | 84 | −3.57% | −1.58% | 0.80% | 0.34% | 2.30% | 3.59% | |
| scar | 0.25% | 0.03% | 2.63% | |||||
| cone | −6.30% | 2.15% | 1.16% | |||||
| Model | Normal (E=1.0 MPa | CCT=0.52 mm) | −2.74% | −3.18% | 1.18% | 1.64% | 1.21% | 0.26% | |
| KC (E=0.5 MPa | CCT=0.48 mm) | −5.45% | −6.53% | 2.33% | 3.31% | 2.42% | 0.56% | ||
| KCT (E=1.0 MPa | CCT=0.48 mm) | −2.75% | −3.20% | 1.11% | 1.62% | 1.21% | 0.28% | ||
| KCM (E=0.5 MPa | CCT=0.52 mm) | −5.44% | −6.48% | 2.45% | 3.34% | 2.41% | 0.52% | ||
Note: The strains in normal corneas, KC1, and KC2 measured by high-frequency ultrasound elastography are presented in the “experimental” section. The strains predicted by finite element models of human eyes with simplified geometry and mechanical properties are presented in the “model” section (E: modulus; CCT: central corneal thickness).