A lens or other part of an optical instrument that interacts with light.
A measuring device with a small window, attached to an upside-down bottle, used to dispense alcoholic drinks in a bar.
Of, or relating to the eye or to vision.
Of, or relating to optics or optical instruments.
The light-related aspects of a device.
Perception, image, public relations, especially in politics.
The physics of light and vision.