Traditional Lens Surfacing

Traditional lens manufacturing has the design surfaced only on the front of a semi-finished lens blank. The progressive design, base curve, and add power were molded on the front surface of the lens using these molds. The RX (distance power) is then ground (surfaced) into the back of the lens using a generator. The lens would then go to the surface finers and polishers to complete the grinding process.
Traditional surfacing is limited in the number of customizations of the progressive designs because of the physical constraints of traditional tools. In addition, traditional surfacing of progressive can only incorporate two facial measurements; the height of your pupil in the frame and the distance between your pupils. One further limitation to traditional surfacing is that it can only correct your prescription in quarter diopter increments and only in the optical center of the lens.

Woman processing lenses at an optical lab
Midland Optical - Technician reviewing lens quality

Digital Lens Surfacing

Midland Optical now has two state of the art digitial surfacing lines! Digitial surfacing uses physical tools and a pre-programmed digital file to surface a job. This technique of surfacing eliminates the limitations that a traditional surfacing has in terms of the number of designs that can be created and complex of curves.

Digital lens Surfacing (also known as "freeform" processing) gives you the ability to customize each lens individually to each wearer providing improved vision. Digital surfacing technology allows labs to produce higher quality lenses. Digital surfacing also allows for more fitting measurements including pupil height, pupil distance, vertex distance, pantoscpic tilt, frame wrap, eye movement, and more. RX can also be measured to a sixteenth of a diopter. Digital surfacing allows us to compensate the prescription throughout the entire lens surface and not just the center of the lens which gives the patient a wider viewing area at all distances. Digital lenses also have greater versatility when it comes to frame fitting, allowing more variety in lens shapes in regards to prescription.

The Benefits:

  • Visual comfort with easy transition between near and far
  • Personalization to each patient for best visual quality
  • Wide viewing areas at all distances
  • Improved peripheral vision
  • Reduced distortion (or swim effect)
Woman examining a lab
Man processing lenses down a conveyor belt

Free-form Technology

The term "free-form" refers to an advanced manufacturing process that reduces higher-order aberrations such as spherical aberration that occur in eyeglass lenses created with traditional eyeglass lens manufacturing tools and processes. Free form technology uses computer-aided design and surfacing to create high-level, customized eyeglass lenses with your unique prescription allowing for a more "tailored" lens customized for your specific prescription and frames.


1833 Knox Ave
St. Louis, MO 63139
Toll Free (800) 325-3176
St Louis (314) 533-2020

2600 Beverly Dr., #101
Aurora, IL 60502
Toll Free (800) 244-7090
Aurora (630) 820-6800

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