a piece of leather
thread for leather and 2 needles
a very sharp cutter
drill with a nail on the front
grease for leathers (optional)
Prior to starting making your case, it is advised that you draw on a piece of paper what exactly you would want your case to look like, making sure you design it and measure it on the exact dimensions you are to make it. Then you need to cut the sketch, make sure it looks exactly as you want it an then take the sketch and put it on the piece of leather. Use it as a guide, quite similar to using a stensil, meaning that you trace your design on the leather piece. That way you can get a perfect result. Ofcourse, the measurements for the case differ according to the dimensions of the glasses you have.
After that, you cut your leather according to your design and you glue the edges, Then, you start making the holes as you wish.
Once you've done that you need to get two needles and the thread and start sewing with this pattern: first you pass through the hole the first needle from the right and then the second needle from the left in the same hole, making sure your thread is the same length on both sides. You follow the same routine throughout all the holes.
When you finish passing the thread through all the holes, at the last hole you need to take one of your needles and pass it again through the previous hole so as to have both needles at the same side to be able to tie a knot. After you have made the knot make sure that you burn the thread a bit to avoid possible fray.
To be able to close your case and know that your glasses are secured in it, you can take a piece of leather and create a string that will allow you to have the safety you wish. Also, in that way, you do not get to use any more materials since you already have the leather, you just take advantage of it. Afterall, my desire is to create different projects by using material that we all might have at home.
An extra tip is to use grease for leathers in order to moisturise your leather and make it softer and waterproof. However, since you are making a case for glasses, remember not to grease the leather on the inside as well, because that would get your glasses dirty. On the inside you can only wax the top part of the case, as it will not touch the actual glasses.