One of the best ways to conceal dilated pupils is to wear sunglasses, according to eHow. Hats and baseball caps that shade the eyes are also a good choice, as they make dilation less noticeable.
Pupils tend to dilate in response to the presence of drugs or poisonous substances in the system, according to eHow. Another way to reduce the effects of pupil dilation is to stay in a well-lit area, since pupils tend to dilate in response to dim lighting. When choosing sunglasses to wear for the purpose of concealing dilated pupils, choose the darkest pair possible, to avoid making your eyes visible through the lenses.