Were you ever able to get your PTS to eat a fairly balanced diet?
Did you ever get him in for a general check up and have a fecal sample checked for parasites? I think it was your PTS that came from a pet store in iffy shape (wild caught) and wasn't eating much besides banana?
The eye problem may be shed related, a symptom of a upper respiratory infection (common in stressed reptiles), there could be a small foreign object stuck under the lid, this could be an injury from something in the enclosure, the PTS could be dehydrated... Your vet can differentiate and treat accordingly. Eyes can go downhill fast, so take this problem seriously.
In the mean time keeping the area clean (no goop) is important- sterile saline eye rinse can be used (you can get this over the counter). This is NOT visine or similar medicated product- plain old saline eye drops should not hurt if your PTS's problem is any of the above- and may help.
Cheers, Jess b