Hi
A normal pupil examination can be documented as being PERL and NO RAPD. This shorthand states that the pupils are equal and reactive to light, and that there is no Relative Afferent Pupil Defect.
So how do I actually test these properly?
I ask to patient to fix in the distance, then i check the pupils are equal in size, and again with the lights off. Then, with the lights still off I check each eye has a direct response to light. Finally I do a swinging light test to check there is no RAPD.
Now lets recap with a little more explanation.
Firstly To avoid the near reflex where the eyes converge, accommodate and the pupils constrict, ask the patient to fix on an object in the distance.
You should check the pupils are equal in both light and dark or you may miss an abnormally small pupil such as is seen in horner's syndrome. For more on unequal pupils watch the video titled anisocoria.
When examining the pupil reactions, having the patient in the dark with distance fixation makes the pupils as large as possible and makes the pupil reactions easier to see.
When you shine the light at the pupil, watch the same pupil for a quick constriction, followed by a slight relaxation.
There is no need to look for a consensual reaction here as both eyes have demonstrated a direct reaction indicating an intact afferent pathway from eye to brain, and efferent pathway from brain to pupil. There is also no need to check for a response to accommodation unless the pupils fail to respond to light.
Finally the swinging light test to check for a relative afferent pupil defect or RAPD. This is a comparative test of the two optic nerves, and may detect conditions such as optic neuritis or optic nerve compression where the nerve is functioning, but poorly when compared to the other side.
Again this should be in the dark with distance fixation. First shine the light at the first eye, the pupil will constrict and then relax a little, now swing the light source, quickly and directly, to the other eye. The pupil will have just started to dilate when the light hits it, causing a small constriction, followed by a relaxation. Make sure you hold the light on each eye for 2 to 3 seconds to allow each pupil to first constrict then relax before you swing the light to the other eye.
Your light source must be bright to reliably detect an RAPD, a standard direct ophthalmoscope or pen torch may not be bright enough.
OK, you have now examined these normal pupils.