You may want to consider Transitions photochromic lenses for your primary pair of glasses. They adjust automatically to changing light conditions to allow just the right amount of light to reach the ...

The two types of concave lenses — biconcave and plano-concave ... For example, a lens designed for applications demanding low dispersion might be made of crown glass. Acrylic and polymer lenses are ...

Standing on shoulders Both types of telescopes ... that by using two different kinds of glass together in the objective lens, they could cause the red and blue ends of the spectrum to converge ...

This type of lens is designed to reduce spherical and optical aberrations without the need for a multi-lens assembly. Small glass and plastic aspheric lenses can be molded, but large glass lenses ...