Description
Label the sign and magnitude of a supplied refraction cylinder.
Eye records preserve laterality, reference axes, chart distance, calibration provenance and geometric scale. Disc-diameter units are a relative image scale, not a physical length, and cylinder sign differs from a full prescription transformation. Supplied labels and conversions do not inspect an eye, detect disease or choose care.
Label the sign and magnitude of a supplied refraction cylinder.
When to use this tool
Use Ophthalmic Refraction Cylinder Sign Label when you already have cylinderDiopters and need to label the sign and magnitude of a supplied refraction cylinder.
How to use the tool and how it works
- Enter cylinderDiopters. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read signLabel, magnitudeDiopters. Use the output convention below.
Return plus cylinder, minus cylinder or zero cylinder according to the sign, together with abs(cylinderDiopters).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| cylinderDiopters | Cylinder Diopters | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| signLabel | Sign Label | Required. Text; maximum UTF-16 length 8192. |
| magnitudeDiopters | Magnitude Diopters | Required. Finite number. |
{
"input": {
"cylinderDiopters": -1.5
},
"output": {
"signLabel": "minus cylinder",
"magnitudeDiopters": 1.5
}
}Limitations and assumptions
- No prescription conversion, refraction measurement, correction adequacy or clinical advice is provided.
- 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
Review the original image calibration, refraction convention and chart-distance record for substantive measurements. Use complete optical or image geometry when physical scale or clinical interpretation is required; relative disc units and axis labels preserve narrower conventions.
References
Similar or alternative tools
- Lens Meridian Power Pair
Calculate orthogonal principal-meridian powers from supplied sphere and cylinder.
- Ophthalmic Meridian Orthogonal Pair
Return an axis and its orthogonal meridian under a half-turn convention.