Pupils differing in size by less than 1 mm may indicate which of the following?

Pupils differing in size by less than 1 mm can be a normal anatomical variation in some individuals, meaning that they are not necessarily indicative of an underlying medical condition. This slight difference can sometimes be observed in healthy individuals and does not cause any symptoms or complications.

In contrast, significant differences in pupil size, especially those reflecting more than 1 mm, could suggest various health issues, such as increased intracranial pressure, optic nerve compression, or substance abuse. For example, significant discrepancies in pupil size may be associated with neurological disorders or reactions to drugs. However, a minimal variance of less than 1 mm is often considered within the realm of what could be a typical characteristic for some individuals, thus reinforcing the idea that this can represent a normal variant rather than a medical concern.