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Eyewear made easier

Know your frames.
Choose with confidence.

Learn about fit, PD, prescriptions, and care.

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Frame fit PD Prescription
basics Frame care
Eyeglass measurements on a real portrait: lens width across the left lens, bridge width between the lenses, and temple length pointing to the arm at the right hinge

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Start here

What do the numbers on your frames mean?

The numbers inside a frame show lens, bridge and temple measurements. Compare them with a pair that already fits.

  • 1Lens width: the horizontal width of one lens, measured in millimeters.
  • 2Bridge width: the distance between the lenses where the frame rests on your nose.
  • 3Temple length: the length of the arms extending toward and behind your ears.
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Your eyewear questions, answered clearly.

Eyewear advice made simple.

52 □ 18 - 140 millimeters
Fit guide

Find your fit

Use a frame you already own to narrow down a comfortable starting size.

Open guide
  1. Check the inside of either temple arm for three numbers.
  2. Compare the lens and bridge measurements first.
  3. Allow a few millimeters of variation for different frame shapes.
  4. Confirm that your eyes sit near the horizontal center of each lens.
62 mm PD
Measurement guide

Know your PD

Pupillary distance helps position the optical center of each lens in front of your eyes.

Open guide
  • Single PD is one total measurement between both pupils.
  • Dual PD lists separate measurements for the right and left eye.
  • For the best accuracy, use a professional measurement when available.
  • Do not guess when ordering prescription lenses.
EYESPHCYLAXISODOS-2.00-0.5090-1.75-0.25105
Prescription guide

Prescription basics

Learn what common abbreviations mean before discussing lens options.

Open guide
  • OD refers to the right eye; OS refers to the left eye.
  • SPH describes the primary lens power.
  • CYL and AXIS relate to astigmatism correction.
  • ADD is additional near power commonly used for multifocal lenses.
balanced width
Style and comfort

Find frames that fit

Shape matters, but comfort, proportions and lens compatibility matter more.

Open guide
  • The frame should not press tightly at your temples.
  • Your pupils should sit reasonably centered within the lenses.
  • The bridge should feel secure without pinching or sliding.
  • Your cheeks should not push the frame upward when you smile.
check the hinge
Smart shopping

Inspect used frames

Check frame condition, fit and wear before buying a pre-owned pair.

Open guide
  • Review the front, temples, hinges, markings and all disclosed wear.
  • Confirm the model, size and included accessories.
  • Ask whether the frame is level and whether the hinges operate smoothly.
  • Plan for professional adjustment and new lenses when needed.
Care guide

Frame care tips

Simple habits can protect lenses, hinges and frame alignment.

Open guide
  • Rinse dust away before wiping lenses.
  • Use lens-safe cleaner and a clean microfiber cloth.
  • Remove glasses with both hands to reduce frame twisting.
  • Store eyewear in a protective case away from excessive heat.
Personalized eyewear guidance

Still unsure? Let’s look at it together.

Bring your prescription, measurements, current frames, or the pair you are considering to a private Zoom consultation.

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Quick answers

Learning Center FAQ

A few important answers before you shop or book a consultation.

Can Specs On Site issue an eyeglass prescription?
No. Specs On Site provides eyewear guidance and shopping support. A valid prescription must come from a licensed eye-care provider.
Can you help me understand the information on my prescription?
Yes. We can explain common fields and help you prepare for an eyewear purchase, but we do not diagnose, prescribe, or replace professional eye care.
What should I bring to a Zoom consultation?
Bring your current prescription, PD if available, a frame that fits you well, and links or photos of any frames you are considering.
Is the $50 consultation fee applied toward a purchase?
Yes. Your $50 consultation fee is applied toward your Specs On Site purchase when your consultation leads to a sale.
What does Premium include?
Premium is $100 per year and includes unlimited Zoom eyewear consultations, priority booking, prescription-upload support, PD and measurement guidance, delivery coordination, and the listed courtesy replacement benefits.

Educational information on this page is provided for general eyewear guidance and does not replace an eye examination, medical advice, diagnosis, or a prescription from a licensed eye-care professional.