Why are both eyes dialated with NO drugs?

The part of the eye that dilates is known as the pupil. It sometimes dilates when you look at someone that you are physically attracted to. This happens because of a chemical reaction in your brain.

Pupils also dilate according to how much light is present to allow better vision. Pupils are dilated when there is little light available. You can test this out by looking in a mirror where there is a lot of light (your pupils should be very small because allowing too much light in damages the eyes). Then look into a mirror where there is less light and your pupils will have dilated.

During a concussion, a person may also have dilated pupils. I'm not sure why, but probably as a result due to the force of impact sustained by the head.