What are the numbers on sunglasses?

What does +3 mean in glasses?

1) The eye size number (it is the size of the lenses on your frame). 2) The bridge size number (the distance between the lenses). 3) The temple length number (it is the size of that part of your eyeglass frame, which rests upon your ears).

What does 52mm mean in glasses?

Glasses Frames- How to choose the right size eye glass frames.

Small 44-47mm
Medium 49-52mm
Medium Large 52-54mm
Large 54-56mm
Extra Large 56mm and up

Is minus 3 eyesight bad?

If the number has a minus (-) sign next to it, it means you’re nearsighted. A plus (+) sign or no sign means you’re farsighted. A higher number, regardless of whether there is a plus or minus sign, means you’ll need a stronger prescription.

How do I know my eyeglass size?

The first number — the eye size — represents the horizontal width of the lenses. In this case, the openings in the frame for the lenses are 48 mm wide. Generally, the eye size of most eyeglass frames will range from 40 mm to 62 mm.

How do I know if my frame is too big?

Your eyeglasses may be too big if they are always sliding down your nose or falling off your face. Your frames should align horizontally with your eyes and tilt slightly forward so the bottom of the frame is closer to the face than the top of the frame.

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What if PD is off by 2mm?

If the PD measured was 2mm off initially, by using a millimeter rule, the net cumulative error might be 4.5mm or more.

Can I order glasses without PD?

If your PD is off, the “optical center” of your lenses will be, too, and your glasses won’t be as effective as they should be. … Lots of optometrists will give you a copy of your prescription but not include your PD. That’s because they know that, armed with both, you can order your glasses online.