I found this cute idea it says it is for kids but I think it would be a great idea for adults. I think though I would sew the edges if possible instead of glue. Not sure if it would be too thick ot not.
Here is the link to the item: I just wanted to post this because I think it is very cute. And I think they would be pretty cheap to make and a lot cheaper than a eyeglass or sunglass case you could buy.
http://www.wrights.com/class/kidscrafts/potholdercase/potholdercase.htm