Corneal lipidosis is a gradual process. The problem is that by the time you can see it (due to build-up in the eyes) is that it's already started causing problems internally. The fat will first start by building up around the organs; it only starts affecting the eyes when it has nowhere else to go.

That being said, as long as the diet is kept varied (and care is taken to avoid an excess of fatty foods) and proper basking temps are provided, this can avoided all together. Corneal lipidosis is very easy to prevent but, unfortunately, once it takes hold it's irreversible.

Remember the old saying: An ounce of prevention is worth a pound of cure.

Here's an old pic of one of my Cuban Tree Frogs, Winky, who came from a hoarder. You can really see the lipidosis in her bad eye