Green’s Dictionary of Slang

derrey n.

[? play on SE derry down, one ‘looks down’]

(UK/US Und.) an eyeglass.

1859		Matsell Vocabulum.
1889–90		Barrère & Leland Dict. of Sl., Jargon and Cant.
1890–1904		Farmer & Henley Sl. and Its Analogues.