If you are short sighted and wear glasses, it can be usefully to have a backup pair in case of loss or breakage. Often this will be a previous owned pair. If you don't have a backup pair, these Beer Can Glasses just may be of interest. You may also like to make them just to see if they really do work like a pin hole camera's lens.

Supplies

Pair of old sun glasses

Beer Can

Tape

Tools:

Scissors

Marker

Pin or Needle

Step 1: Cut Out a 'lens'

Pop out the lens from a pair of old sun glasses. The ones I used were scratched.
Draw around the lens on to a sheet of aluminum made from a beer can with a marker.
Cut out, following the drawn line.

If you want instructions on how to make a piece of aluminum sheet from a beer can just follow theses instruction: Follow first few steps to make aluminum sheet.

Step 2: Make the Lens

Using a pin or needle, make a row of holes in the cut out piece.
Make a total of four rows of holes spaced about 2 millimeters apart.
Use a pin to make sure the holes are complete.
Slightly bend the lens by rolling against an edge. This is so it will fit the contour of the glasses frame better.