Binoculars work by intensifying and focusing the light that comes through the lenses so you can see further. This creates problems when you come to use them in particularly bright environments, such as the desert where it can cause damage to the viewers eyes if he looks through them at bright light for too long. One way to get around this is to reduce the size of the lenses so that less light enters the binoculars and in turn the user’s eyes. Rather than permanently modify the binoculars, the British Army in World War II issued a set of moderating glasses which would clip over the eyepieces of binoculars to reduce their size:

These moderating glasses were stored in a small, velvet lined leather case when not needed:

The case has a couple of loops sewn to the back that allows it to be worn on the strap of the binoculars, or the strap of the binocular case:

The top of the case has the contents stamped into the leather:

These moderating glasses are an interesting and fun little accessory for my collection of World War II binoculars, although I must admit I don’t expect to have too much need for them in the UK!