Single Vision:
Single vision lenses are good for one point of focus. They are
either for distance or reading. They are available in all lens
materials.
Lined Bifocals: Lined
bifocals allow for two areas of focus, both distance and near. The
most popular type of lined bifocal contains a half moon like segment
that comes in various sizes. The size of the segment is determine by
the patients lifestyle. A lined bifocal is available in all lens
materials.
Trifocals: Trifocal lenses are
the same as lined bifocals but with a third area of focus. Another
line is added above the normal bifocal line giving an intermediate
or arm length range. Trifocals are also available in all lens
materials.
Progressives: Progressive
addition lenses (PAL) are lenses with multiple points of focus.
These lenses give distance, near, and all of the points in between.
Progressive lenses are also known as no line bifocals. Because there
is no line, they look like single vision lenses making them more
attractive.
Computer Lenses: Computer lenses
are similar to progressives in that they have no line. They are set
up in such a way that they give you a working distance, an
intermediate range, and a reading area. The intermediate area is
wider than that of a progressive lens. Computer lenses are available
in plastic and polycarbonate and can be tinted. An anti reflective
coating is generally added to reduce the glare from the computer
screen.