Dilation is an important part of a complete eye exam. Dilation causes your pupils to widen and allows your eye care provider to better view the retina at the back of your eye. This allows for a more complete diagnosis of the eye, including the presence of any diseases or conditions, including diabetes, high blood pressure, macular degeneration, retinal detachment, or glaucoma.  Eye dilation can make your vision blurry and more sensitive to light. You may want someone to drive you home after a dilated eye exam. It can take between four to six hours for your pupils to return to their normal size.