Trolands

Part of speech: noun

Definitions

1. A unit measuring the amount of light reaching the retina of the eye, equal to the illuminance of a surface multiplied by the area of the pupil
2. A measure of retinal light stimulation used in vision research, calculated from the luminance of a source and the size of the pupil through which it is seen
3. A photometric unit describing how much visual stimulus the eye receives, named after the American psychologist Leonard Troland who devised it

Etymology: A troland is a unit of retinal illuminance, the amount of light reaching the eye, and the plural "trolands" simply counts several of these units. The unit is named after Leonard Thompson Troland, an American psychologist and researcher whose work on vision led to a standard measure of how much light the eye receives from a given source and pupil size. Because the unit scales with pupil area, it lets researchers compare light levels across different viewing conditions without worrying about how wide each observer's pupil happened to be.