Table 1.
Descriptive statistics of flat and steep keratometry (diopters [D]), axis (°), form factor, surface regularity index (SRI), and surface asymmetry index (SAI) measurements for the control group and the three study groups
| Group | K flat (D) | K steep (D) | Steep axis (°) | Form factor (k) | SRI | SAI |
|---|---|---|---|---|---|---|
| Control | ||||||
| Mean | 42.83 | 44.35 | 91.85 | 0.96 | 0.91 | 0.61 |
| SD | 2.02 | 2.17 | 27.15 | 0.63 | 0.62 | 0.65 |
| Min | 32.36 | 33.48 | 0.15 | −0.20 | −0.46 | −0.11 |
| Max | 50.94 | 54.01 | 179.86 | 6.30 | 3.01 | 5.38 |
| Group A (LASIK) | ||||||
| Mean | 38.20 | 39.50 | 87.78 | 2.62 | 1.60 | 1.01 |
| SD | 4.50 | 4.23 | 42.09 | 2.18 | 0.78 | 0.98 |
| Min | 23.93 | 25.28 | 4.42 | 0.07 | −0.11 | 0.12 |
| Max | 45.57 | 47.04 | 179.75 | 10.61 | 3.52 | 6.31 |
| Group B (keratoconus) | ||||||
| Mean | 42.45 | 45.71 | 93.85 | 2.96 | 1.88 | 2.96 |
| SD | 3.90 | 3.65 | 46.78 | 1.96 | 0.71 | 2.89 |
| Min | 31.00 | 39.49 | 1.15 | −0.05 | −0.26 | 0.10 |
| Max | 53.98 | 58.07 | 179.79 | 10.47 | 3.60 | 20.47 |
| Group C (Athens Protocol) | ||||||
| Mean | 43.29 | 46.39 | 95.51 | 2.42 | 2.09 | 3.02 |
| SD | 4.22 | 4.72 | 39.43 | 1.91 | 0.63 | 2.33 |
| Min | 34.79 | 35.43 | 13.00 | −0.84 | 0.13 | 0.18 |
| Max | 53.75 | 57.52 | 179.23 | 7.27 | 3.25 | 10.31 |
Abbreviations: LASIK, laser-assisted in situ keratomileusis; max, maximum; min, minimum; SD, standard deviation; K, keratometry; D, diopters.