Scopes are a great tool for professional and nonprofessional uses. Night Vision Scopes help to observe in darkness. Normally you use both eyes (Binocular vision) to pick up cues to help estimate the distance and depth of an object. However, with Scopes you are essentially using one eye (Scope vision), which can pose real problems.

Night Vision Scopes are characterized by magnification, angular field of view, lens's diameter, exit pupil distance etc.