Monocular

The pirate was observing the sea with his monocular.

...one of his sparks alighted upon my eye and destroyed it making me a monocular ape;

You are not such a foolish woman as to like to be seen with Fred Mostyn, that little monocular snob, after the aristocratic, handsome Basil Stanhope.

The moony monocular set in his eye / Appeared to be scanning the Sweet Bye-and-Bye.

Monoculars are designed to fit discreetly in the hand, improving their cosmetic appearance. Most monoculars sold today have one primary optical difference from binoculars: the ability to focus at close range. These are known as short-focus telescopes.