Description
Reorient an optical-center offset to a temporal-positive convention.
Optical records distinguish sphere/cylinder powers, principal meridian axes, prism-base labels and eye-specific offset signs. A radial lens-blank margin is half its diametral margin under centered circular geometry. Local optical formulas and code labels do not perform refraction, verify fit or prescribe a lens.
Reorient an optical-center offset to a temporal-positive convention.
When to use this tool
Use Frame Optical Center Decentration when you already have frameCenterCoordinate, opticalCenterCoordinate, positiveMeansTemporal and need to reorient an optical-center offset to a temporal-positive convention.
How to use the tool and how it works
- Enter frameCenterCoordinate, opticalCenterCoordinate, positiveMeansTemporal. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read temporalPositiveDecentration. Use the output convention below.
Return (opticalCenterCoordinate-frameCenterCoordinate)*(positiveMeansTemporal?1:-1).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| frameCenterCoordinate | Frame Center Coordinate | Required. Finite number. |
| opticalCenterCoordinate | Optical Center Coordinate | Required. Finite number. |
| positiveMeansTemporal | Positive Means Temporal | Required. Boolean. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| temporalPositiveDecentration | Temporal Positive Decentration | Required. Finite number. |
{
"input": {
"frameCenterCoordinate": 30,
"opticalCenterCoordinate": 32,
"positiveMeansTemporal": true
},
"output": {
"temporalPositiveDecentration": 2
}
}Limitations and assumptions
- Coordinates and eye-side convention are supplied; no pupil position, optical effect, fit or prescription 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
Use the complete verified optical prescription and lens/frame geometry for a design or fit analysis. Preserve sphere-cylinder axis and eye-specific direction conventions; a meridian sum or centered circular clearance is only one part of that calculation.
References
Similar or alternative tools
- Dental Arch Midline Offset
Reorient a dental-midline difference to a right-positive convention.
- Lens Meridian Power Pair
Calculate orthogonal principal-meridian powers from supplied sphere and cylinder.