Description
Relabel supplied prism components under explicit signs without deriving a lens prescription.
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.
Relabel supplied prism components under explicit signs without deriving a lens prescription.
When to use this tool
Use Prism Base Axis Sign Token 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 horizontal, vertical, positiveBaseOut, positiveBaseUp. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read baseOutComponent, baseUpComponent. Use the output convention below.
Return baseOutComponent=horizontal and baseUpComponent=vertical with independent sign reversals when positiveBaseOut or positiveBaseUp is false.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| horizontal | Horizontal | Required. Finite number. |
| vertical | Vertical | Required. Finite number. |
| positiveBaseOut | Positive Base Out | Required. Boolean. |
| positiveBaseUp | Positive Base Up | Required. Boolean. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| baseOutComponent | Base Out Component | Required. Finite number. |
| baseUpComponent | Base Up Component | Required. Finite number. |
{
"input": {
"horizontal": 2,
"vertical": 3,
"positiveBaseOut": false,
"positiveBaseUp": true
},
"output": {
"baseOutComponent": -2,
"baseUpComponent": 3
}
}Limitations and assumptions
- Horizontal and vertical components need one prism/measurement scale. This records a supplied sign convention rather than inferring eye side, combining optical prescriptions, or deciding a clinically appropriate prism.
- 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
- Lens Axis Wrapped Angle
Wrap an explicitly supplied unoriented research axis to a half-turn coordinate; no prescription is generated.
- Lens Cylinder Axis Unit Flag
Convert a supplied axis unit and optionally normalize a 180-degree orientation; no prescription calculation.