eyepieces
n. 目镜( eyepiece的名词复数 )
The eyepiece of a microscope or telescope is the piece of glass at one end, where you put your eye in order to look through the instrument.
Water won't hurt these binoculars, but raindrops on your eyepieces will definitely spoil your view.
虽然雨水不能损坏这具望远镜, 但落在目镜上的雨滴会令望远镜中的景物模糊.