Eye Care Providers (either ophthalmologists or optometrists) dilate eyes with drops. These drops vary from provider-to-provider. Some use drops that are uniform for the kind of problem that patient has.
For many providers, the same dosage or kind of drops are used equally whether it is a general examination for which no medical history risks or an examination to treat the eye with medicine or surgery. Thus the pupil may react differently because each patient may react differently to these drops. But providers tend to use the same drops no matter what the circumstances are.
In summary, it is not unusual for pupils to remain dilated even a day after the appointment.