Odd

Something odd happened today.  This afternoon I was going over some comprehension questions with Haylee and Hannah.  They had made corrections and I was going to finish it orally so they didn't have to spend a lot of time on the work.  We started going over the last few things and I noticed Hannah's eyes were extremely dilated.  I questioned myself about what could be causing the stress.  We had just started and we only had a few things to do before we were finished.  I wasn't stressed at all and she hadn't been in trouble.  Hannah was sitting to my left and Haylee was sitting to my right.  I looked at Haylee's eyes and back to Hannah's.  There was a huge difference in the dilation.  I asked a question and Haylee answered.  I didn't tell her if it was correct or not before asking Hannah the same question.  She was stuttering and closing her eyes.  I stopped and asked Hannah to come to me.  We were maybe a foot apart.  She came and I hugged her and told her I love her and she is safe with me.  What we are doing doesn't tell how much I love her or accept her.  I love her and she is my daughter and I am proud of her.  Haylee just giggled as she watched.  I had her sit back down and her eyes hadn't changed.  She could talk better, but her eyes were still dilated.  It was very odd.  She struggles with her words when she is the least bit nervous.  I guided her througth the answers because I knew in her state, she wouldn't be able to answer on her own.  I made it much easier for them and we finished up. 

I wonder what triggered this event?  The only time she has had the eye dilation before was when she was in trouble.  She had just come home from piano and played outside for a few minutes before we started. 

Is there any way to figure out what triggers these events or is it just trial and error?  This was a totally different situation than any in the past.