The green eyeshade, poker visor or casino dealers visor.
The green visor started life as protection against the harsh light created by early electric light bulbs in the late 19th early to mid 20th centuries
The visor was worn by accountants, telegraphers, newspaper copy editors and other people who worked in detailed vision intensive occupations to reduce eyestrain. Not sure if it worked although green light is said to be a restful colour.
The green eyeshade is also associated with gambling as croupiers used to wear them possible for a similar reason as accountants, although they may have also hidden the eyes somewhat making it harder to read people.
This is a cheap fancy dress eyeshade, but still usable.
