•Single Vision – Single vision occurs when an individual is near sighted or far sighted, but not near sighted and far sighted.
•Bifocal FT-28 – A lens with two points of focus – usually one for distance and one for near vision. Bifocal portion of lens is in the shape of a half moon.
•Progressive Bifocal – A no-line multi-focal lens that includes all corrections, from distance to close-up, in one lens without any separation of the visual zones by a line.
You can call your eye doctor for this measurement, or you can measure your own PD using a mirror and a millimeter ruler. Your prescription does not typically show the pupil distance measurement.
To measure the PD yourself, place the ruler flat against your forehead and with your right eye closed, line up the zero on the ruler with the center of your left pupil.
With your left eye closed, take a reading of the ruler at the center of your right pupil.
If you have difficulty seeing what you are doing, then use a magnifying mirror. If it is easier, line up the outside of the iris of one eye with the inside of the iris of the other eye and use that measurement.
We need your distance PD on the order form if you are ordering distance or bifocal glasses, and your near PD on the order form if you are ordering reading glasses. Your near PD is 3mm less than your distance PD, as your eyes move closer together when you read. For adults, the typical PD measurement is from 54 to 66. If you do not supply your PD measurement, we will set distance optical center at 65mm for men and 63mm for women.
Only one measurement is necessary. Any adjustments needed for reading or bifocal glasses will be made by us.
If you enter incorrect prescription information such as an inaccurate papillary distance measurement, you may not be able to see well with your new glasses. We cannot be responsible for mistakes in prescription information provided by you or your optometrist or ophthalmologist. We guarantee that your prescription safety glasses will be made exactly to the specifications that you provide.
Standard Plastic – Plastic is lightweight and more impact resistant than glass but it scratches easily.
•Polycarbonate – Polycarbonate, a plastic, is the most impact resistant material available for glasses. Polycarbonate is UV resistant and about 50 times stronger than other lens materials.
•Glass – Glass is scratch resistant and provides the clearest possible vision. It is heavier than plastic, but is the most durable lens on the market.
•High Index Plastic – Lenses correct vision by bending light as it passes through the lens. High index plastic lenses are able to bend light more than the conventional plastic used for lenses. This means that high index plastic lenses are thinner and lighter than conventional plastic lenses.
•Trivex – Trivex is a high impact lens with optical qualities closer to glass lenses. It has an index of refraction of 1.53, the same as glass or standard plastic so high prescriptions will be thicker. Trivex Material has UV protection built into the lens.