The significance of changes in pupil size during straylight measurement and with varying environmental illuminance

Conclusion We conclude that the illuminance of the examination room during straylight assessment does not affect the outcome in normal eyes. In fact, under mesopic and scotopic conditions, the luminance of the test field is so much higher than that of the room so that it determines the pupil size. Regardless of the lighting level, straylight measured in a laboratory, is valid for photopic pupils at an adaptation level corresponding with about 400 lux room illuminance.
Source: Journal of Optometry - Category: Opthalmology Source Type: research