Description
Supplied reduced-eye planar scale times angle or tangent, without an individual eye biometry or retinal magnification model.
Vision research uses stimulus angles, chart notations, image scales, viewing distances, coordinate origins, and observation windows. These quantities have different denominators and measurement conventions. A conversion or support share does not independently establish a visual measurement or its clinical interpretation.
Supplied reduced-eye planar scale times angle or tangent, without an individual eye biometry or retinal magnification model.
When to use this tool
Use Retinal Image Angle Length Factor when you need this image, stimulus, notation, coordinate, or observation component for supplied research data.
How to use the tool and how it works
- Enter angleRadians, eyeScaleLength, exactTangent. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read retinalLength, smallAngleLength. Use the output convention below.
For positive eyeScaleLength and angleRadians strictly between -pi/2 and pi/2 return retinalLength=eyeScaleLength*tan(angle) if exactTangent, otherwise eyeScaleLength*angle. Always return smallAngleLength=eyeScaleLength*angle.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| angleRadians | Angle Radians | Required. Finite number. |
| eyeScaleLength | Positive geometric projection scale in the desired retinal-length unit. | Required. Finite number; strictly above 0. |
| exactTangent | Use tangent rather than its small-angle approximation; not anatomical exactness. | Required. Boolean. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| retinalLength | Retinal Length | Required. Finite number. |
| smallAngleLength | Small Angle Length | Required. Finite number. |
{
"input": {
"angleRadians": 0.1,
"eyeScaleLength": 17,
"exactTangent": false
},
"output": {
"retinalLength": 1.7000000000000002,
"smallAngleLength": 1.7000000000000002
}
}Limitations and assumptions
- Eye scale is a supplied geometric length and angles are signed radians. ExactTangent means exact within that tangent-plane model, not an anatomically exact retinal projection or a patient-specific ocular measurement.
- 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 calibrated acquisition and a documented visual or imaging protocol for complete interpretation. Confirm the reporting notation, viewing geometry, image scale, and support of the underlying observations.
References
Similar or alternative tools
- Visual Angle Stimulus Size
Return the exact centered planar stimulus angular width from supplied compatible dimensions, without an acuity score.
- Visual Field Solid Angle Small Angle Term
Solid angle of an ideal centered rectangular angular patch versus its small-angle product, without a visual-field test interpretation.