Different corneal power maps are displayed by the Pentacam®::
- Sagittal and Tangential Power map
- Refractive Power map
- True Net Power map (TNP)
- Total Corneal Refractive Power map (TCRP)
Pentacam® measures height (elevation) data. These are converted into curvature (mm) and then converted into power values (diopter).
Different factors are taken into consideration to calculate the different power maps of the Pentacam®:
- The refractive effect (Snell’s law of refraction)
- Inclusion of anterior/posterior surfaces
- Correct refractive indices used
- Location of principle planes (Ray tracing)
| Refractive effect | Inclusion anterior/posterior surface | Correct refractive indices used | Ray tracing | |
| Sagittal map | ||||
| Refractive power map | x | |||
| TNP | x | x | ||
| TCRP | x | x | x | x |
Above table shows the factors used to calculate the different power maps.
