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health.retinal-illuminance Calculator
Calculates retinal illuminance in trolands from luminance and pupil area, accounting for Stiles-Crawford effect in photopic vision. Retinal illuminance is the quantity that drives photoreceptor bleaching and adaptation — relevant for display design and ophthalmologic research.
Inputs
Pupil Diameter Mm
Distance across a circle through its centre. Always confirm units match the rest of the calculation.
Scene Luminance Cd M2
Reference formula or conversion factor shown for context.
Results
retinal illuminance (lux at retina)
The value at the specified point or condition.
pupil area (mm²)
The computed two-dimensional surface area.
troland (td = L × A_pupil mm²)
Sample size or count used in the calculation.
E_retina = L × A_pupil / f²
Sample size or count used in the calculation.
scotopic vision
Sample size or count used in the calculation.
safe exposure
Reference formula or conversion factor shown for context.