HBP will not cause dilated pupils. Pupils get big in the dark, when angry or excited, due to drops or some medications, during some types of migraines, with head trauma.
See a ophthalmologist Eye MD to work through the causes. Find one at www.aao.org
My daughter who is 13 years old last night complained she could not see well and everything is blurry. I picked her up from school and noticed both eyes very dilated. I call the Dr. He referred her to the local eye care center. The Eye Dr. Did the minimal eye examine and determined she got eye medicine in her eyes...both eyes pupils do not move with light. I asked if she has taken any drugs or put medicine her eyes....she said no. Dr. Said nothing else can make her eyes stay dilated???? I beleive her. She has not bumped head, no pain, and nothing got in her eyes. She was fine a couple of days ago. He told us to get some readers from the drug store and in a about 2 weeks he should be fine. What is wrong with her eyes?
You may have to take your daughter to her regular doc for more testing. There are quite a few things, some common, some temporary, and some dangerous, that can cause dilated pupils. I don't know if medhelp will allow this link, but I'll try posting it. If the whole link shows up (no asterisks) , take out the word dot between the words answer and com, and put a period in that place (no spaces).
If that doesn't work, google the phrase 'dilated pupils in teenagers'.