Indications for subject exclusion from the analysis
| Parameter | Eyes (n) |
| Previous corneal surgery (PK, LVC, RK or PTK) | 14 |
| Other corneal disease (KCN, ectasia, PMD, corneal scars) | 15 |
| CDVA less than 6/12 | 23 |
| No postoperative refraction | 58 |
| Incomplete biometry or out of range of any formula | 27 |
| Both eyes operated on (random exclusion) | 419 |
KCN, keratoconus;LVC, laser vision correction;PK, penetrating keratoplasty;PMD, pellucid marginal degeneration; PTK, phototherapeutic keratectomy;RK, radial keratotomy.