The Case is worked seamless in the round without joining. You could easily add alternate closures. I used a spring loaded closure clip as found on commercial cases, too. The process of sewing in that clip is included in the pattern.

Because of sharp edges on my closure clip, I had to sew a lining into the top seam. But depending on the yarn type and hook size you use, the fabric should be stiff enough to apply such a clip without lining, if you get good ones.

The size depends on your glasses, I have explained how to determine it. You could use any yarn you want, gauge should be checked but is not crucial.

If you have any questions or comments, I would love to help you.