Table 1.
Pentacam Criteria for Risk of Keratectasia
| Criteria | Normal | Suspect | Abnormal |
|---|---|---|---|
| Pentacam | |||
| K max (D) | < 47.2 | 47.2–49 | > 49 |
| Against the rule astigmatism (D) | < 1 | 1–2 | > 2 |
| Corneal astigmatism (D) | < 6 | 6–7 | > 7 |
| Thinnest point (μm) | > 500 | 470–500 | < 470 |
| Difference between pachy apex and thinnest location (μm) | < 10 | 10–20 | > 20 |
| Difference in central thickness between 2 eyes (μm) | < 10 | 10–30 | > 30 |
| Displacement of the thinnest point from the center (mm) | < 0.5 | 0.5–1 | > 1 |
| Skewed steepest radial axis (SRAX) (degrees) | < 10 | 10–20 | > 21 |
| IS value (inferior–superior difference at the 3 mm) (D) | < 1.4 | 1.4–1.9 | > 1.9 |
| IS value (inferior–superior difference at the 5 mm) (D) | < 1.4 | 1.4–2.5 | > 2.5 |
| Anterior elevation (μm) | < 10 | 10–12 | > 12 |
| Posterior elevation (μm) | < 15 | 15–17 | > 17 |
D= diopter; IS value = the inferior-superior value.