What does 5 mean in glasses?
Lens power is measured in diopters. The higher the number, the stronger the prescription. For example, “-5.00” written under sphere means that you are very nearsighted and need a five diopter correction.
What do the little numbers on my glasses mean?
The numbers beneath the frames reflect the SIZE MEASUREMENTS in millimeters (mm). THE FIRST NUMBER (ex.54) = the width of the lenses. THE SECOND NUMBER (ex.15) = the distance between the lenses. THE THIRD NUMBER (ex.140) = the length of the temple arm including the portion going behind the ear.
Are CR 39 lenses good?
That is where CR-39 lenses (Wikipedia link) improve on glass. It’s optical quality is almost as good as glass (and far better than all the other options we will look at), it is half as heavy as glass, it is much more resistant to shattering, and still very resistant to scratches.
What does Plano mean for glasses?
If your prescription has the word Plano, PI, or an infinity sign, it means that you do not have distance problems. You may, however, have astigmatism. Most values will be 0.00 to +/-20.00. Axis. Axis is the lens meridian that has no cylinder power to correct astigmatism.
Is 5 eyesight bad?
Deciphering your eye prescription should be less about how “bad” it is, and more about how vision correction can improve your eyesight. The goal of glasses and contacts is always 20/20 vision, no matter what your prescription reads.
What is the difference between CR-39 and polycarbonate?
Polycarbonate lenses have a higher index of refraction (1.586) than CR-39 plastic (1.498) and are therefore thinner in an equal lens prescription. With a higher index (of refraction), light is bent more efficiently, therefore it requires less material to achieve the eyeglass prescription making the lenses much lighter.
What is NV add on zenni?
There may also be a fourth section on the Rx labeled NV-ADD (for Near Vision-Reading ADDition), which could be used to order a pair of bifocal or progressive glasses with a close-up vision section in the bottom part of the lens.