Description
Parse an explicit signed sphere/cylinder and integer axis token without selecting a 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.
Parse an explicit signed sphere/cylinder and integer axis token without selecting a prescription.
When to use this tool
Use Lens Prescription Plusminus Axis 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 token. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read sphere, cylinder, axisDegrees. Use the output convention below.
Accept an explicitly signed decimal sphere, slash, explicitly signed decimal cylinder, lowercase x, and a 1-3-digit integer axis within zero through 180. Return finite sphere, cylinder, and axisDegrees.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| token | Explicit signed sphere/signed cylinder x axis notation, with lowercase x. | Required. Text; maximum UTF-16 length 8192. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| sphere | Sphere | Required. Finite number. |
| cylinder | Cylinder | Required. Finite number. |
| axisDegrees | Axis Degrees | Required. Safe integer. |
{
"input": {
"token": "-2.00/-1.25x090"
},
"output": {
"sphere": -2,
"cylinder": -1.25,
"axisDegrees": 90
}
}Limitations and assumptions
- Whitespace, unsigned powers, exponent notation, and other clinical notations are unsupported. This token parser does not validate a prescription, map axis endpoints, assess visual need, or recommend eyewear.
- 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.
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 Transposition Cylinder Axis Wrap
Algebraic sphero-cylinder transposition with axis normalized to [0,180), not a prescription recommendation.
- Lens Cylinder Axis Unit Flag
Convert a supplied axis unit and optionally normalize a 180-degree orientation; no prescription calculation.