Table 1.
The novel Q value-based nomogram [12]
| Q-anterior |
CTO < 450µm
Degree/µm |
CTO 450–500µm
Degree/µm |
CTO > 500µm
Degree/µm |
|---|---|---|---|
| More than - 0.50 | 210/150 | 210/150 | 210/150 |
| - 0.50 to > - 1 | 210/150 | 210/200 | 210/250 |
| - 1 to - 1.50 | 210/200 | 210/250 | 210/300 |
| Less than - 1.50 | 210/250 | 210/250 | 210/300 |
Abbreviations: CTO, corneal thickness at the optical zone; µm, micrometers. Note: The values are indicated as Keraring segment (Keraring ICRS, Mediphacos Ltd., Belo Horizonte, Brazil) arc length in degrees/thickness in µm; Q-anterior, asphericity of the anterior corneal surface; “more than” and “less than” should be considered with respect to mathematical signs.