There are many different types of night vision optics that can be used to help a person see in low light conditions. The different devices are typically categorized both by the type of device it is, with regards to how it is intended to be used, and the type of technology it uses, often referred to by generation. Common types of optics with different uses include binoculars, monocles, gun scopes, and goggles. Differences in the technology used in night vision optics are usually indicated by generation, with at least generation one through four being commercially available.
Night vision optics are devices that can be used by a person to more easily and effectively see in low light or near perfect dark conditions. These devices are often used by military and law enforcement, as well as by search and rescue crews. Their use by civilians can be restricted in many countries, especially devices intended for use with firearms such as night vision scopes. The first night vision optics devices, sometimes referred to as generation zero, were developed during World War II and used active infrared lights, though later versions used only passive light amplification.
One of the primary ways to categorize night vision optics is by the intended use of a device. Such devices often can be found as binoculars and monocles intended for use while held to the eyes. This allows for effective night vision, and newer devices even include proximity detectors that automatically turn the device on and off. Night vision scopes that can be connected to a gun, even with other types of scopes, can often be found though they may be restricted in some areas to military and law enforcement use only. There are also night vision optics that can be found as goggles, often worn with a strap around a person’s head or connected to a helmet.
Night vision devices are also often categorized based on the technology used in such devices. Generation one devices are still commercially available, though the image quality of such devices is far less than generation three and four devices. Later generations also typically include other features, such as digital controls and automatic shut off functions that protect a user’s vision by automatically shutting down the device when exposed to bright lights. This is important since most night vision optics devices utilize light amplification to function, and so exposure to bright lights can potentially damage a user's vision.