Assess if pupils are equal and reactive to light (PEARL)
Before checking in patients eyes use caution where patients may have been having recent seizures, because you might induce another seizure by directing a light in their eyes.
Report if unequal, however, remember that 25% of the population have naturally unequal pupils, this is called anisocoria, This aside the pupils should be equal and reactive.
Ask the patient if they have anisocoria, if they can’t answer, ask someone who knows them,
Note: if you shine light in one pupil, both will react.
Do not use very bright lights to test this. LED torches can actually blind someone. If you are unsure of the brightness, test the light in your own eyes – if it’s too bright you, it’s too bright for them!.
Generally, one blown and dilated pupil indicates head injury (stroke or trauma).
Bilaterally dilated, non-reactive pupils could possibly indicate brain death. However, if the patient was in cardiac arrest and given epinephrine and atropine, the pupils will be dilated and non-reactive. Therefore they are not necessarily brain dead but it cannot be ruled out.
Small pinpoint non-reactive pupils could indicates drugs overdose, although some synthetic drugs that do NOT cause this, so don’t use normal pupils to rule out drugs overdose.
Bilaterally dilated pupils that DO react could be because of fear, dark ambient light or non-endogenous sympathomimetic drugs used for heart failure or cardiogenic shock, hypovolemic shock, septic.