What are the active ingredients in this product? I would be warry of something so broad spectrum as an antifungal and impaction remedy. Sounds like false faith derived by coincidence to me, if that makes any sense.
It is common for white's tree frogs to get corneal lipidosis. I believe it's an age, high colesterol thingy, but it's been a few months since I've read up on it. Either way, get it examined by a herp vet because without following the proper procedures, the treatment could be worse than the problem.
Without knowing what exactly is going on, additional safe advice would be to re-evaluate the husbandry, including making sure the cage and water are maticulously clean. This might mean moving to a seperate quarantine cage if a natural and/or communal vivarium are currently being used. Additionally, while these frogs are normally fat, they can definately be overly obese which might be related to your problem. Consider cutting back on food in increments, and use food that is low in caleries, but still high in nutrition. Gut loaded insects versus baby mice for example.
Ian