Dilation of the eyes is part of a more comprehensive vision examination. Dilation involves one eye drop for each eye. The drop allows the pupil to open widely, giving you doctor a more extensive view to the health inside your eyes (like having a larger keyhole to spy into a room). The drops work within 10-15 minutes, but will keep your pupils big for a few hours. Most people have no difficulty driving home with sunglasses, but many experience blur with small print for a few hours. There is no additional fee involved for this procedure.