Mydrilate is what's causing your large pupil (it's an anti muscarinic), pred forte is an anti-inflammatory (corticosteriod) eye drop (long term use of this MAY increase intra-ocular pressure which you doctor will keep a check on), betnesol you probably put in at night before you go to sleep and can't administer the Pred Forte drops - it's also a corticosteroid, but also contains neomycin - an antibacterial agent - to prevent or help reduce secondary bacterial infection.
The Mydrilate will only be administered so the doctor can have a much better view of the internal workings of your eye when you're examined on the slit lamp..
I was also on all three of these over Christmas and have had them in the past. The Mydrilate in my case had a much longer term impact than expected - one single drop caused my pupil to remain dilated for over 60 hours...apparently this extended effect is more common in people like me with blue eyes! Completely prevented me from driving for about five days, but the PredForte really did the business.
Hope you get better soon, I know how miserable it is!
