Contact Lens Design & Materials

Amazing Lathing: A Glimpse into GP Lens Manufacturing

BY DAVID L. KADING, OD, FAAO

When we stop to think about how our GP and custom soft contact lenses are made, we can be amazed at the work that goes into creating these wonderful medical devices that give our patients sight. When I sit down to work with one of my patients on a new fit, I tend to overlook the vast complexity that goes into the creation of a GP lens. Following is a glimpse.

Placing the Order

Whether it’s a standard spherical lens, a keratoconus design, or a scleral lens, the system is about the same, but the data input varies. First, your lens needs to be ordered. Depending on the way you work with your lab, you can do this by fax, internet, or phone.

I personally call, or have one of my staff members call, to order all of our lenses. The customer service at my lab is second to none, and they walk me through any questions that I have or material choices that I need to make.

The Manufacturing Process

Next, the lens is placed in a queue. This may mean a tray, bag, or order assembly line. The order then gets a button selected that fits the material choice that we make. What happens next may vary depending on the lab. Essentially, that material button needs to be blocked onto a firm setting so that when placed adjacent to a lathing device, it won’t move.

The design data is then input into a computer, and the lens begins its lathing process. Most labs cut the anterior surface of the lens first and then remove the lens and reblock it from the other side. The lens is then placed in another lathe to cut the posterior surface.

To see a video of an automated system that is being incorporated by many of our larger labs (courtesy of Josh Adams at Valley Contax),     click here. This automated system helps to streamline the manufacturing process and allows the lathes to be run around the clock.

Final Steps

Once the lathing process is completed, the lens is cleaned and verified. At this stage, the lens would also undergo plasma treatment, if requested, which removes impurities from the lens surfaces and helps improve lens wettability and comfort. Plasma treatment of GP lenses is standard in many labs now, and it should be.

Then, the finished lens is taken over to shipping and sent out to your office. Some labs ship to more than 500 accounts every day. That alone is a masterful feat, especially because many of us use labs that would be considered family owned and operated.

Show Your Appreciation

To all of this, I take off my hat and say “Bravo!” It is because of our labs’ designs, systems, and processes that I look like a hero on a daily basis. So, the next time you talk to your lab representatives, stop and say thank you for all that they do to cut costs, streamline systems, and make you look awesome. CLS

Dr. Kading owns the Specialty Dry Eye and Contact Lens Center in Seattle. He is the co-owner of Optometric Insights with Dr. Brujic. He has received honoraria for consulting, performing research, speaking, and/or writing from Alcon Laboratories, Allergan, Bausch + Lomb, Biotissue, Contamac, Essilor, Nicox, Oculus, RPS Detectors, TearScience, Valley Contax, and ZeaVision. Follow him on Twitter @davekading.