Description
Compare supplied bench frame and pupil coordinates in one axis basis.
Optical calculations distinguish lens power in diopters, prism notation, angular axes, geometric distances, and visual-acuity reporting scales. Sign conventions and length units are especially important when a formula combines power with decentration or vertex distance. A supplied model term is separate from a validated visual test or prescription.
Compare supplied bench frame and pupil coordinates in one axis basis.
When to use this tool
Use Frame Decentration Reference Gap when you need this explicit optical, chart, frame, axis, or reference conversion with compatible supplied units.
How to use the tool and how it works
- Enter frameCenter, suppliedPupilCoordinate, referenceDecentration. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read decentration, referenceGap. Use the output convention below.
Return decentration=frameCenter-suppliedPupilCoordinate and referenceGap=decentration-referenceDecentration.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| frameCenter | Frame Center | Required. Finite number. |
| suppliedPupilCoordinate | Supplied Pupil Coordinate | Required. Finite number. |
| referenceDecentration | Reference Decentration | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| decentration | Decentration | Required. Finite number. |
| referenceGap | Reference Gap | Required. Finite number. |
{
"input": {
"frameCenter": 35,
"suppliedPupilCoordinate": 30,
"referenceDecentration": 4
},
"output": {
"decentration": 5,
"referenceGap": 1
}
}Limitations and assumptions
- All coordinates and the reference need one length unit and origin. The result is signed frame-minus-pupil geometry, not a detected pupil center, validated fitting standard, or clinical recommendation.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use the appropriate complete optical or measurement model when a scalar term is insufficient. Verify power, axis, length, notation, and reference conventions before applying the result within a broader assessment.
References
Similar or alternative tools
- Spectacle Asymmetric Frame Decentration Pair
Explicit planar model decentration and conservative circular-blank budget, without selecting spectacle fitting measurements.
- Optometric Trial Frame Vertex Reference
Paraxial thin-lens vergence transfer F/(1-dF) through signed distance d, without a patient vertex-distance prescription.