What Final BAD-D represents
The Belin/Ambrósio Enhanced Ectasia Display combines deviation information from several tomographic domains into a final multivariate index. It is designed to highlight ectatic-pattern deviation relative to the device reference database. Final BAD-D is therefore a composite signal, not a direct measurement such as micrometers or diopters.
The component family
Commonly displayed components include deviation measures related to anterior elevation (Df), posterior elevation (Db), pachymetric progression (Dp), thinnest pachymetry (Dt), and relational thickness or ARTmax (Da). Software labeling and reference data should be checked against the installed Pentacam version and manufacturer documentation.
Interpret the final value with its components
Two examinations can have a similar Final BAD-D for different component reasons. Reviewing which domains contribute helps the surgeon distinguish an elevation-driven, thickness-driven, or mixed pattern. The composite should be considered with raw maps, examination quality, and the rest of the clinical evaluation.
Important evidence boundary
Published sensitivity and specificity estimates depend on the population, case definition, comparator, software version, and chosen threshold. They should not be transferred automatically to every refractive-surgery population or used as proof that a separate software product has been validated.
Final BAD-D disposition
| Final D | Classification | CER-AI pathway result |
|---|---|---|
| <=1.60 | Normal | PASS |
| >1.60 and <2.60 | Suspicious | CAUTION |
| >=2.60 | Abnormal | STOP-DEFER |
| Unavailable | Unavailable | ASSESSMENT INCOMPLETE |
Final D is read from the BAD Display bottom strip. CER-AI never reconstructs it from Df, Db, Dp, Dt, or Da.
What each BAD-D component means
| Field | Technical meaning | Do not confuse with |
|---|---|---|
| Df | Standardized deviation of the anterior elevation difference map: the change from the standard best-fit sphere to the enhanced reference surface | F.Ele.Th, which is the signed anterior elevation at the thinnest point in µm |
| Db | Standardized deviation of the posterior elevation difference map: the change from the standard best-fit sphere to the enhanced reference surface | B.Ele.Th, which is the signed posterior elevation at the thinnest point in µm |
| Dp | Standardized deviation of the average pachymetric progression pattern from the reference population | PPI Average, the displayed underlying progression index |
| Dt | Standardized deviation associated with the measured minimum/thinnest corneal thickness | The raw Thinnest Location pachymetry in µm |
| Da | Standardized deviation of ARTmax (Ambrósio Relational Thickness maximum) | Raw ARTmax, calculated by Pentacam as thinnest-point thickness divided by PPI Maximum |
| Final D | Pentacam multivariable regression output integrating the BAD display parameters against its reference database | A sum, average, percentage risk, or patient-specific lifetime probability |
Df, Db, Dp, Dt, Da, and Final D are reported as normalized deviations from the device reference framework. They are dimensionless standardized values, not micrometers or diopters. A larger deviation means farther from the reference mean; it does not by itself establish a diagnosis.
How CER-AI carries BAD information into the report
| BAD Display value | CER-AI handling | Independent use elsewhere |
|---|---|---|
| Final D | The source-locked printed value alone determines the BAD-D pathway result shown above | Remains independent from ERSS, NICE, and PS3 |
| Df, Db, Dp, Dt, Da | Transcribed from the bottom D strip and displayed as component context; they are not independently rescored | No component creates a second BAD-D caution or stop |
| F.Ele.Th / B.Ele.Th | Transcribed separately from the labeled elevation row as signed µm measurements | These raw elevation values may enter explicitly named NICE or PS3 pathways; they are not replaced by Df or Db |
| PPI min/avg/max; ARTmax | Transcribed separately from the Progression Index box as raw device outputs | PPI Average has a separately defined PS3 role; Dp and Da do not substitute for it |
CER-AI preserves both the printed value and its exact source region. An isolated abnormal component can coexist with a normal Final D, while several smaller deviations can contribute to an abnormal Final D; therefore the report shows the component pattern without reverse-engineering or overriding the printed composite.
Selected sources
- Belin, Acta Ophthalmologica 2025
- Bamdad et al., Journal of Ophthalmology 2020
- OCULUS Pentacam manufacturer documentation
See the complete CER-AI medical reference registry for broader context.