Table 6.
Spearman ρ and confidence interval of correlation of change in CH, change in CRF, preoperative CH, and preoperative CRF with CCT, ablation depth, RSB, and percentage of tissue altered.
| Variable | Preop CH | Preop CRF | Δ CH | Δ CRF | CCT | Ablation Depth | RSB | PTA |
|---|---|---|---|---|---|---|---|---|
| Δ CH | ||||||||
| ρ value | −0.474* | −0.390* | NA | 0.692* | −0.185 | 0.379* | −0.046 | 0.271* |
| 95% CI | −0.619, −0.299 | −0.551, −0.201 | NA | 0.567, 0.785 | −0.416, −0.027 | 0.189, 0.542 | −0.248, 0.160 | 0.071, 0.451 |
| Δ CRF | ||||||||
| ρ value | −0.344* | −0.544* | 0.692* | NA | −0.186 | 0.452* | −0.106 | 0.384* |
| 95% CI | −0.512, −0.149 | −0.674, −0.382 | 0.567, 0.785 | NA | −0.427, −0.041 | 0.273, 0.601 | −0.307, 0.097 | 0.194, 0.546 |
Δ = change; CCT = central corneal thickness; CH = corneal hysteresis; CI = confidence interval; CRF = corneal resistance factor; NA = not applicable; PTA = percentage of tissue depth altered [(flap thickness + ablation depth)/ preoperative CCT]; RSB = residual stromal bed
*
Statistically significant (P value of correlation <.0001).