light adaptation

The human visual system adapts to varying light intensities through several mechanisms. The iris adjusts the pupil size, opening in dim light and constricting in bright light, to control the amount of light reaching the retina. This adjustment can alter image brightness significantly, with some animals exhibiting even greater pupil control for survival in diverse light conditions.12

Vision in low light relies on rods, which are highly sensitive to single photons but do not perceive color or fine detail. In brighter conditions, cones take over, providing color vision and detail, though they are less sensitive than rods. The visual system also adjusts the signal transduction process and the availability of photopigment molecules to manage a wide range of light intensities.13