What is +0.00 in reading glasses?
Generally, if your glasses prescription indicates that there is no need for focusing power, you will have good vision. On the other hand, the further you go from zero (whether that number is positive or negative), the worse your vision becomes and the more you need to have your eyesight corrected. Therefore, +1.00 and -1.00 are quite modest; your eyesight is not too bad; you only require 1 diopter of correction. However, if your prescription is +4.50 or -4.50, you will require more clearness. A stronger prescription will be needed, at 4.5 diopters of correction.
What markings must be on the lenses and frames of your safety glasses?
There must be a manufacturer or supplier certification mark on all safety lenses, frames (front and temple), removable side shields, and other parts of the glasses, goggles, or helmet which are deemed suitable for use in hazardous conditions.
In the same way that plano safety frames must be stamped with the manufacturer’s logo or mark, prescription safety glasses must also be stamped with the standards that they comply with – such as “Z87-2” for prescription safety glasses or “Z87-2+” for safety glasses that meet impact standards.
What does spectacle frame markings mean?
The lens width, the bridge width, and the temple length are all measured on the inside of one arm of glasses frames, and these numbers stand for the lens width, bridge width, and temple length. The lens width and the bridge width are often distinguished by a small square shape that is placed on the inside of the arm and may be separated by spaces or dashes.