When ordering your uncut lenses there are several things you can do to help ensure the best cut out and avoid costly redos. One of the most important frame measurements is the ED, yet we consistently see this has the most confusion on how to get the correct measurement. This blog will show you the correct way to measure a frame's ED.
As most of us know, in this industry, being off by even just a millimeter can be the difference between a happy patient and a frustrated patient that could leave your business a bad review. A patient's Rx is an exact science, so making sure you provide these when entering your orders will help not only to ensure the patient receives precisely what they need, but also have the least amount of adaption issues after dispensing.
Many times we see orders with the LD (longest diameter) of the lens placed incorrectly in the ED (effective diameter) box. While this number may be close, it is not correct and can wreak havoc on making the patient's glasses right the first go around.
I won't link to it here, but even the top snippet on Google incorrectly states the LD as the ED! As a wholesale lab that depends on the accuracy of the information provided to us by our customers, this is maddening.
The Correct Way To Measure Frame ED
The first thing you'll need to do is box the frame as shown below:
As you can see, boxing the frame is fairly simple. You're simply creating a box around the outside of the frame by making 2 horizontal lines at the top and bottom of the frame. Then create 2 vertical lines on either side of the frame. The top and bottom lines provide you with your A measurement of 51mm while the 2 vertical lines provide your B measurement of 35mm.
Now, you just need to find the geometric center of the lens. You can do this by making an X between the corners of your box for the frame as shown below:
As you can see, once you draw the X, your geometric center is shown at the center of it. From here we can get the correct ED measurement. The ED measurement is twice the distance of the farthest point from the geometric center as shown below:
The green line above now indicates the ED for this frame. Using this example, the green line measures 27mm. As mentioned above, we just need to multiply 27mm by 2 which gives us the correct ED of 54mm.
Using this method will always give you the most accurate ED which allows us, your optical lab, to make the most accurate lenses possible for your patients. A properly measured ED, along with the other accurate frame measurements means you will not only get the best cut out but also the best thickness for each job you order.
Option 2: Let Your Edger Do The Work
Another easy way to get the correct ED measurement is to let your edger do it for you. Most edgers these days will not only trace the frame for you but also provide you with all of the exact frame measurements. You can use these measurements while placing your order and then simply store them after you receive the job to quickly edge your uncut lenses.
Not only is this one of the most accurate methods available to you, but it also saves time after you get the job back so it's a double win!
You can also utilize our frame shape numbers when placing your orders on our myIcareLabs customer portal. Providing accurate frame measurements along with the shape number that most closely matches the patient's frame should help drastically cut down remakes for cut-out issues.
We hope this clears up any confusion you may have with getting the correct ED measurement for a frame.