I found these products at Quilt Market in Houston, and I use them a great deal. I found a site for them in Australia.
As you can see the larger one is clipped to my machine. I don’t generally use if for sewing, however, I have to stop quite frequently and sew the threads into the body of the quilt… so I use this magnifier when I’m threading the needle and to make sure the threads are up to standard.
The other picture are lenses that clip to your glasses, I use these when I’m doing really fine illustrations and I can also sew with them on… They magnify the image about 60%. They are not bulky and I can easily whip them on and off…. I guess the drawback for these is that you actually have to wear glasses to use them.