Description
Convert a supplied axis unit and optionally normalize a 180-degree orientation; no prescription calculation.
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.
Convert a supplied axis unit and optionally normalize a 180-degree orientation; no prescription calculation.
When to use this tool
Use Lens Cylinder Axis Unit Flag 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 axis, suppliedDegreesPerUnit, normalizeHalfTurn. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read degrees, normalizedDegrees. Use the output convention below.
For positive suppliedDegreesPerUnit convert axis*factor into finite degrees. Return degrees and, if normalizeHalfTurn, normalizedDegrees as a nonnegative modulo-180 value; otherwise preserve degrees.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| axis | Axis | Required. Finite number. |
| suppliedDegreesPerUnit | Supplied Degrees Per Unit | Required. Finite number; strictly above 0. |
| normalizeHalfTurn | Normalize Half Turn | Required. Boolean. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| degrees | Degrees | Required. Finite number. |
| normalizedDegrees | Normalized Degrees | Required. Finite number. |
{
"input": {
"axis": 200,
"suppliedDegreesPerUnit": 1,
"normalizeHalfTurn": true
},
"output": {
"degrees": 200,
"normalizedDegrees": 20
}
}Limitations and assumptions
- Factor maps the supplied angle unit into degrees. Zero and 180 are equivalent only on the normalized branch, and no lens-power transposition, anatomical axis, or clinical prescription validation is performed.
- 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 Transposition Cylinder Axis Wrap
Algebraic sphero-cylinder transposition with axis normalized to [0,180), not a prescription recommendation.