These lenses may cause the liquid crystal displays on the dashboard of cars to appear invisible.

It represents the distance at which the mirror or objective lens will cause light to converge on a single point.

Brown lenses are common among golfers, but cause color distortion.

Transparent lenses caused little distortion of the underlying grid.

The strong lens "could cause all kinds of trouble," he said.

These decorative lenses can cause permanent eye injury and may potentially lead to blindness.

People who usually wear contact lenses may have more trouble in coping with their symptoms, because the lenses cause further irritation to the eye.

Some ophthalmologists say they worry that the lens may cause infections in eyes so vulnerable.

With aging, the crystalline lens of the human eye causes straylight to become worse.

Brown lenses cause some color distortion, but also increase contrast.