Box/Housing - a metal or plastic container to house the whole instrument and prevent light from spilling in unwanted directions.

Because the lid prevents light from reaching the film, the rest of the film developing process may be carried out in daylight.

This prevents light from passing clearly through a the lens, causing some loss of vision.

In the case of using wet newspaper, the multiple layers prevent light from reaching all plants beneath, which kills them.

The surgeon will provide the patient with a cover for his or her eyes that prevents light from entering.

The refractive index of water prevents light from being deviated at smaller angles.

If necessary, use a shield to prevent stray light from reaching the detector.

Window shades were tightly drawn to prevent light from reaching the outside darkness.

A problem prevents light from entering the eye for a long period of time.

The pond is covered to prevent stray light from setting off the phototubes.