How are Prescription Glasses Made?

Working a prescription into a lens is akin to shaping and polishing a fine piece of wood. And that’s just part of the process.

Making Prescription Glasses

Prescription glasses take many stages of processing before they are ready to be sent to the customer. From pulling the lenses to grinding the prescription, edging to coating, there is an array of different processes that must be carefully completed in a specific order.

Prescription eye labs such as ours must be equipped with a prescription generator, fining and polishing machines, edging machines, coating machines, lens tinters, and a lens meter. The machinery must also be constantly calibrated, coolant and polish replaced and filtered, and lenses inspected and reinspected. To keep an optical lab running correctly is like maintaining a complex machine.

Here is how prescription glasses are made here at Rx-Safety:

  1. Pull the frame: When your order comes into the lab, we pull the frame and a pair of semi-finished lenses from stock and put it into a tray with a slip that details your order.
  2. Enter your prescription: Next, we enter your prescription into our lab computer system and use a tracing machine to trace the frame’s lens pocket. The tracing is saved along with the prescription so all of our employees and machines have the information they need to make your glasses correctly.
  3. Block the lenses: Next, your semi-finished lenses are blocked. Blocking is the process of fixing a small round tool to the front of a lens in such a way that our machinery can hold the lens by this tool, but it will come off the lens without damaging it at the end of the process.
  4. Generate your prescription: Once the lenses are blocked, we generate your prescription into them. To maintain the woodworking analogy, imagine that this is the first rough sanding. The prescription is generated into the lens, but it is so rough that the lens is basically opaque.
  5. Fining and polishing: Next, your lenses move to fining and polishing. They go through several stages of polishing where the rough prescription is polished using finer and finer polishing pads (like using finer and finer sandpapers on wood) until they are polished using buffing pads in the last stage. This is all done in machines that keep lens polish flowing onto the lenses as the machines polish them.
  6. Inspection and coating: After fining and polishing, the lenses are inspected. They then may be coated in-house or sent out of house for a coating.
  7. Edging: Next, the lenses are edged. We use CNC edging machines which take the shape of your frame and the optical center of your lenses into account as they edge the lenses to the appropriate shape and size to fit into the frame.
  8. Inspection, tinting, and coating: After this, your lenses are inspected again and may be tinted or sent out for a coating.
  9. Lens insertion and inspection: Lastly, the lenses are inserted into the frame and inspected for defects including scratches, prescription errors, and frame symmetry.
  10. Packing and shipping: If the glasses pass final inspection, they are packed and shipped out to the customer!

Your prescription lenses are inspected several times throughout the process to ensure that any errors are caught right away so they can be amended. It is very important to us to get your prescription glasses out as quickly as possible, and to get them out right. If we make a mistake, we do our best to discover and repair it right away to minimize delays.

Our lab produces thousands of prescription lenses a week and even more non-prescription. We have polishing and fining machines for glass and plastics so that we can create almost any sort of prescription in-house, and we have some of the most advanced edging machines in existence today.

Because there are many moving parts to the creation of prescription lenses, and because many people must be involved, we do our best to engender a sense of teamwork and accomplishment here at Rx-Safety, and we hold office contests and parties regularly to celebrate the accomplishments and dedication of our team.

If you have any questions about how prescriptions are made or what we can do, leave a comment below or give us a call. Thanks for reading!

  1. Tyler Johnson says:

    That’s good to know that each pair of glasses would be made custom for you. I would think that would make your vision as good as possible. I’ll have to consider getting some prescription glasses made for me.

    • rxsafety says:


      Thank you for the comment. We make every pair of eyeglass lenses custom here and would love to earn your business. I hope you give us a try one day.

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