It's a common misconception that you have to exchange your U.S. license within one year.
You can drive using that license for one year, but after that it is not valid to drive here. You can convert for up to 5 years.
My memory is a tad rusty but you'll need the eye exam and you'll give over your U.S. license temporarily. It will be returned with either a sticker or stamp saying it's not valid here. I think my license took a few weeks and it was around 100 Francs. The eye exam shouldn't be more than 25-ish.