Hi I am Dr. Trace and I would like to help you with your question.
The first thing that comes to mind is an enlarged pupil with a droopy eyelid. This is every ophthalmologist's concern and a third nerve palsy must be ruled out. I am assuming that this was done since you said you have seen several different ophthalmolgists over 8 times in the last 8 weeks.
So - what can be a cause for a red/ slightly or intermittantly painful eye with a puffy eyelid? Even with no uveitis, the cornea can be abraded or irritated. I would recommend you lubricate the eye frequently during the day - 5 to six times a day - with an artificial tear preparation like systane or blink. Then at bedtime, I would recommend a gel like refresh pm. Put this in the eye at bedtime because it will blur your vision slightly.
Do this for a few days. If your symptoms do not resolve, you must return to the ophthalmologist to get to the cause of your symptoms. Finally, I cannot think of a link between oral prednisone and corneal irritation so I doubt this is the cause of your ocular symptoms.
I hope this helps.