examples of eyeglasses
The shape of glasses varies depending on the period and their use (e.g., correcting far- or nearsightedness, protecting the eye, magnifying).
opera glasses 
Optical magnifying instrument held in front of the eyes; it is used for looking at relatively close objects such as at the theater.
monocle 
Single lens held in place under the ridge of the eyebrow.
lorgnette 
Glasses held in front of the eyes by a handle attached to the side of one rim.
pince-nez 
Glasses whose frame has a spring bridge that grips the nose.
sunglasses 
Glasses with lenses that filter the sun’s glare to protect the eyes.
scissors-glasses 
Lorgnette whose lenses fold back over one another and can be slipped into the handle, which also acts as a case.
half-glasses 
Glasses with half lenses to correct farsightedness; the empty space above them is used to see distances.