Green eyeshade

Green eyeshades or dealer's visors are a type of visor that were worn most often from the late 19th century to the mid-20th century by accountants, telegraphers, copy editors, and others engaged in vision-intensive, detail-oriented occupations to lessen eye strain[1] due to early incandescent lights and candles, which tended to be harsh (the classic banker's lamp had a green shade for similar reasons).

[2] Because they were often worn by people involved in accounting, auditing, economics, and budgeting, they became associated with these activities.

[3] Green eyeshades were often made of a translucent dark green- or blue-green-colored celluloid, although leather and paper were used to make the visor portion, as well.

[5] The Society of Professional Journalists annually recognizes deserving journalists working in the Southern United States with its Green Eyeshade Excellence in Journalism Award.

[6] The phrase "green eyeshades" can be used as a synecdoche for individuals who are excessively concerned with financial matters or small and insignificant details.