A skin scrape is typically performed so the area can be cultured. A culture and sensitivity typically show the type of fungus and the antifungals it is sensative and or resistant to. This helps determine the course of treatment. As a differential though, corneal lipidosis presents as cloudy eyes in frogs that are typically older and have had excessively fed throughout their lives and is not a fungal infection. However I mention this only as an aside and I do not dispute your vet’s findings. What treatment was offered? Was this an exotics vet? Was quarantine advised?