So far there is no solid evidence that snakes are especially afraid of fire, and they do have poor eyesight. If you encounter a snake, it is a much better idea to avoid excessive movement, as they are attracted to it. Those who need to keep snakes out of their garden and away from their home might want to try spraying sulfur around the area, as it has been known to keep them at bay.
If you have a snake inside your house, it is recommended that you contact wildlife control as soon as possible. Although fire might seem like a good way to scare away snakes, it is not particularly efficient with an unexpected encounter with one.