16/05/2026
(The accompanying image is for illustrative purposes only)
Imagine looking in the mirror brushing your teeth, only to realize one of your pupils is suddenly twice the size of the other.
That is exactly what happened to a healthy 25-year-old lady who rushed into the clinic, understandably terrified.
When a patient presents with unequal pupil sizes (anisocoria), our medical instincts immediately jump to the worst-case scenarios. Is it an intracranial pathology? An expanding aneurysm? A brain tumor? A stroke?
A thorough neurological examination was performed. Cranial nerves? Completely intact. Extraocular movements? Perfect. No headaches, no blurry vision, no limb weakness, and no trauma. She was neurologically pristine, except for that one glaringly dilated pupil.
So, what caused it?
The culprit wasn't a brain emergency. It was her antiperspirant wipes, bought from an online store.
Many antiperspirant wipes contain anticholinergic agents which block acetylcholine, turning off the signal to the sweat glands.
The patient used the antiperspirant wipe on her face and inadvertently rubbed or touched her affected eye and the anticholinergic medication was absorbed locally, blocking the parasympathetic receptors in that eye.
Without acetylcholine to constrict the pupil, the sympathetic system went unopposed, causing the pupil to dilate widely and she was left with striking, unequal pupils.
I advised the patient to stop using the wipes temporarily. At her follow-up review a few days later, the problem was completely resolved. Her pupils returned to normal and symmetric. No expensive scans, no invasive test, just the natural clearing of a topical side effect.
Sometimes, patient may experience relatively harmless conditions which look terrifying. While we must always rule out life-threatening conditions, meticulous history-taking is sometimes the most powerful diagnostic tool a doctor has.
It also highlights a vital truth about healthcare, not every terrifying symptom requires an immediate trip to a specialist or an emergency department.
Navigating the healthcare system effectively means using the right services at the right time. A properly trained General Practitioner (GP) possesses the diagnostic skillset to look at the whole picture, filter out the true emergencies, and solve complex clinical puzzles right in the clinic.
Before rushing for an expensive MRI or a specialist referral, starting with your family doctor can save you unnecessary anxiety, time, and intervention.