Does the size and amount of pinholes matter?
I've seen other types of pinhole glasses for much less, and much more. Does the size and shape of the pinholes matter?
Yes, of course it matters. Obviously, if the "pinhole" is two inches in size, it will not work. If the "pinhole" is too small, it will not work either. The size of the pinhole relates to the distance from the eyes, and the distance between pinholes is also important. The size of a pinhole in a pinhole camera changes the way it works. The size is related to the wavelength of light, and to interference patterns. This is true of glasses as well. There is an optimal range of sizes for most people. Likewise, the shape is important, and round seems to work best. However, some people's eyes work better with slits rather than pinholes! There is also an optimal amount of distance between the pinholes, and the area between should be opaque. Here is a simple test you can do. Get a "Teaspoon" type tea infuser, which is made out of metal with pinholes in it. Look through it. Now compare that to looking through a wire mesh type. The wire mesh, even if the holes are smaller, will not work as well because the distance between the holes is too small. Now look through a regular spaghetti collander. The holes are too large, and are not optimal. Take a sheet of something opaque, like thin plastic or manilla folder paper. Make pinholes of different sizes, and peer through them. (Try to make "clean" holes.) You will see that a certain range of hole size works best, but within that range there is little difference.
Conclusion: YES it makes a difference. The proper range for hole size should be between 1 mm and 1.3 mm. The distance between holes should be approximately twice the size of the holes. (2.0 mm to 2.6 mm) The balance of pinhole size, placement, distance between holes, opaqueness of material, and distance mounted from the eyes is in the optimal range with these glasses. If you find anything else, or material that is not opaque, try them out to see if they work at all for you.
As for price, I have seen standard magnifying reading glasses go for a wide range of prices too, but keep in mind, these are not just a fashion statement, these glasses can actually help your eyes heal!
Magnifiers almost ruined my eyes. Pinhole glasses (and eye exercises) brought them back. The price on this pair is very good, much less than many others, and well worth many times more when you consider what you should be willing to pay for good eyesight.