When observing unequal pupils in a patient, what should be documented first?

Documenting the size and reaction time of each pupil is crucial when observing unequal pupils, also known as anisocoria. This assessment provides essential initial data that can help determine the underlying cause of the unequal pupils. By noting their size, healthcare professionals can identify if one pupil is significantly larger or smaller than the other, which can indicate various neurological conditions or injuries. Additionally, reaction time to light helps assess the function of the optic and oculomotor nerves, offering further insight into the patient's neurological status.

Recording these details first is important because it establishes a baseline for further evaluation and treatment. If there are abnormalities, it guides the urgency of treatment and the need for further assessment or intervention. Other options, while they may be important in a broader clinical context, do not provide immediate necessary information for assessing the current situation regarding unequal pupils. For instance, prior medical history may be useful later, but it doesn't take precedence over immediate physical findings that directly impact acute care decisions.