Pre- and 18-month postoperative results (±1 SD) in untreated eyes (n=22) corneal wave-front higher-order aberrations
| Parameter | Preoperative (μm) | 18 months (μm) | Difference (μm) | p Value |
| Root mean square | 3.08±1.39 | 3.10±1.48 | +0.02 | 0.7 |
| Coma | 2.74±1.44 | 2.82±1.52 | +0.08 | 0.1 |
| Trefoil | 0.85±0.43 | 0.81±0.39 | −0.04 | 0.3 |
| Spherical aberration | 0.03±0.47 | −0.03±0.48 | −0.06 | 0.2 |
| Secondary astigmatism | 0.60±0.32 | 0.55±0.29 | −0.05 | 0.4 |
| Quatrefoil | 0.21±0.11 | 0.17±0.08 | −0.04 | 0.003 |
| Secondary coma | 0.32±0.24 | 0.31±0.22 | −0.01 | 0.8 |
| Secondary trefoil | 0.15±0.09 | 0.13±0.08 | −0.02 | 0.3 |
| Pentafoil | 0.06±0.03 | 0.08±0.06 | +0.02 | 0.2 |