Are you sure that your eyes are not be dilated temporally? There are many situations that can lead to eye dilation. Such as fear or being attracted to someone. Generally, these reactions are small and the pupil will become slightly more dilated, and again it is only temporary. It usually corrects itself immediately. Drugs can also affect the dilation of the eye. Some illegal drugs also cause the eyes to dilate.
If your eyes are unnaturally dilated and do not respond to light, you should seek medical attention immediately. So if you eyes are not going back to normal, you'd better take care of it, because it may be something serious. Eye doctors can dilate eyes during an exam with eye drops. If you have had your eyes dilated for an exam, you must be careful when going outside. You should wear sunglasses outside until your eyes have returned to normal.
I suggest you to find out whether you eyes dilated temporally or not, if it happens often, you'd better go see the doc.