Description
Return an axis and its orthogonal meridian under a half-turn convention.
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.
Return an axis and its orthogonal meridian under a half-turn convention.
When to use this tool
Use Ophthalmic Meridian Orthogonal Pair when you already have axisDegrees and need to return an axis and its orthogonal meridian under a half-turn convention.
How to use the tool and how it works
- Enter axisDegrees. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read firstAxisDegrees, orthogonalAxisDegrees. Use the output convention below.
Require axisDegrees in [0,180); return the input and (axis+90)%180.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| axisDegrees | Axis Degrees | Required. Finite number; minimum 0; strictly below 180. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| firstAxisDegrees | First Axis Degrees | Required. Finite number. |
| orthogonalAxisDegrees | Orthogonal Axis Degrees | Required. Finite number. |
{
"input": {
"axisDegrees": 30
},
"output": {
"firstAxisDegrees": 30,
"orthogonalAxisDegrees": 120
}
}Limitations and assumptions
- The axis is supplied; no image, refraction, orientation measurement or clinical interpretation is inferred.
- 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.
- Angular Similarity Degrees Radians Label
Convert a supplied angular similarity value between degrees and radians.