It is often surprising how a sight, smell or even a sound can take the mind back to something experienced many years previously. This happened to me recently when I saw what I later learned were called Bed Prisms Spectacles. These are also known as Bed Reading Glasses. They are the oddest looking spectacles you could imagine. They reminded me of a TV program I saw many years ago.
This TV program showed an experiment so on of which, at that time, was truly astounding! The experiment was to discover how the human intellect could adapt itself to having everything it saw INVERTED or ugly! Imagine that. The sky would be down and the ground would be up where the clouds need to be.
Now, this wasn't a swift 'Try these on for a few minutes' type of try. It actually entailed your brave volunteer wearing a couple the craziest looking spectacles for a number of weeks during all his / her waking hours.You can also find out more facts via http://www.classicspecs.com/collection/mens-eyeglasses/.
They contained mirrors fitted to much spectacle frame which turned everything he saw ugly. They were very heavy and cumbersome even so the 'guinea pig' persevered and kept them on each time he was awake for most days, as required from the scientists.