Dehydration is one of the most worrisome complications of diarrhea in children. Mild diarrhea usually doesn't cause significant fluid loss, but moderate or severe diarrhea can. Severe dehydration is dangerous; it can cause seizures, brain damage, even death. Know the signs of dehydration.
Prozac may cause dilated pupils, double vision, blurred vision, and dry eyes. It can also cause eye pain, eye lid infection (blepharitis), cataracts, glaucoma, ptosis (eyelid droop), and an inflammation of the iris (iritis).
I know for a fact that a very, very high dose of Dexedrine (dextro-amphetamine) causes pupils to dilate. Dex is the active ingredient in Adderall. Everyone responds so differently to meds that itt wouldn't surprise me if your dilation is Adderall related at therapeutic doses.