What is the average range for pupil size in direct light?

The average range for pupil size in direct light is generally accepted to be between 2.0 mm and 4.5 mm. This range reflects the physiological response of the pupils to bright light, where they constrict to reduce the amount of light entering the eye and protect the retina. The lower limit of 2.0 mm represents a typical constriction response, while the upper limit of 4.5 mm accounts for variations in individual responses and situational factors that might influence pupil size.

Understanding pupil size is critical in the context of drug recognition because certain substances can cause pupils to constrict (miosis) or dilate (mydriasis) outside of the normal range, which can indicate the presence of specific drug influences. Recognizing these variations helps in assessing a subject's impairment and forming conclusions about their drug use status.