Table 3.
Anterior-posterior surface area in normal, forme fruste keratoconus (FFKC), and keratoconic eyes.
| Normal | FFKC | KC | N vs. FFKC | ||
|---|---|---|---|---|---|
| (n = 25) | (n = 14) | (n = 23) | (P-value) | ||
| Anterior Surface area | 5 mm (mm2) | 20.154 | 20.147 | 20.403 | 0.62 |
| 6 mm (mm2) | 29.370 | 29.380 | 29.796 | 0.41 | |
| 7 mm (mm2) | 40.545 | 40.579 | 41.194 | 0.33 | |
| Posterior Surface area | 5 mm (mm2) | 20.389 | 20.430 | 20.917 | 0.06 |
| 6 mm (mm2) | 29.881 | 29.953 | 30.662 | 0.07 | |
| 7 mm (mm2) | 41.513 | 41.642 | 42.592 | 0.13 | |
| As/Ps | 5 mm | 0.988 | 0.986 | 0.976 | <0.01 |
| 6 mm | 0.983 | 0.981 | 0.972 | <0.01 | |
| 7 mm | 0.977 | 0.974 | 0.967 | 0.04 | |
| Ab/Pb | 5 mm | 1.192 | 1.216 | 1.284 | 0.01 |
| 6 mm | 1.196 | 1.218 | 1.329 | 0.01 | |
| 7 mm | 1.196 | 1.214 | 1.297 | 0.02 | |
FFKC: forme fruste keratoconus, KC: keratoconus, N: Normal, VA: visual acuity, As: anterior surface area, Ps: posterior surface area, Ab: anterior best-fit sphere, Pb: posterior best-fit sphere.