Nightlight

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For other uses, see Nightlight (disambiguation).

A nightlight is a small light source, usually electrical, placed for comfort or convenience in indoor dark areas or areas that become dark at certain times.

[edit] Use and culture

People often use night lights for the sense of security they provide them. Besides their usefulness to children in the allaying of their fears, night lights are also useful to the general public by showing the general layout of a room without turning on a major light, for avoiding tripping over stairs or obstacles, or to mark an emergency exit. Exit signs often use tritium in the form of a traser.

There are a wide variety of nightlights. Most based on incandescent bulbs have a power usage of less than 10 watts; lights based on more efficient technologies, e.g. neon lamps and LEDs, use 1 watt or less. They sometimes have a light-sensitive switch which activates them only when it is dark enough for them to be required. Some others even include an integrated rechargeable battery so that the light will continue to function during power outages.

[edit] Nearsightedness

At least one study [1], at the University of Pennsylvania, indicated that sleeping with the light on or with a night light was associated with a greater incidence of nearsightedness in children. A later study [2] at Ohio State University, however, contradicted the earlier conclusion. Both studies were published in the journal Nature.