Fix and Fit
Fitting small lenses in the frame
By Alex Yoho, ABOM

In the previous Fix and Fit column, we discussed the importance of working with your lab to ensure proper lens measurements by doing two things. First, by matching your equipment's calibration to those of your lab. Second, by providing your lab with as as much information as possible about lens dimensions.

Still, there are times when the lenses are just plain small. Depending on how small they are, you may be able to get by and refit the in their intended frames by using a few tools of the trade.

While some would consider this cheating, if you have a frustrated patient on your hands, you would do well to have a few tricks up your sleeve just in case--even if you have to do it to get by until another lens is made.

It's also nice to be able to save the day when you didn't make the eyewear. Then you get to play the enviable role of hero to your customer.

Methods of fitting small lenses into frames include using adhesives and clipping and resoldering frame wires

ENCOURAGING A FIT

So what can you do? There are several tried-and-true strategies that will help a small lens stay in a frame using, literally, sticking power. Following are a few tips that can help keep lenses in their frames:

Lens washer. There are several types of lens washer on the market. These include acetate (both thick and thin), nylon, silicone, and two-sided sticky tape.

The most common type of lens washer is the acetate type. Both acetate and nylon should probably not be used if you have to go more than half way around the lens.

Though it's difficult to hold the washer against the lens edge as you put it back in the frame to mount, the process can be facilitated by soaking the acetate in acetone or other chemicals available that are made specifically for this purpose.

This soaking process chemically melts the surface of the washer and makes it sticky so that it will adhere to the lens. The washer is also softened by these chemicals and, as a result, it will then tend to shape itself to the lens.

Two-sided sticky tape. Since nylon is not affected by these soaking chemicals, the two-sided sticky tape may make sure the washer adheres to the lens. The sticky tape can also be used by itself if the lens is only slightly small for the customer's frame.

I like to peel back the protective layer slightly and then start the tape, holding it with my index finger. Then I stretch the tape slightly, which causes it to conform tightly to the lens. You can usually go all the way around the lens with the tape by itself since it is so thin.

Silicone or latex. Another trick in fitting small lenses into a selected frame is to use a liquid in the eyewire that, when dry, becomes a cushion as well as a washer. This liquid can be free-flowing silicone adhesive, or a latex goop which goes on white but dries clear. With either substance, you should be sure to let the material dry thoroughly before mounting the lens.

DON'T STICK WITH GLUE

If you are considering gluing the lenses into the frame, consider it again. This is one messy job!

It probably will cause problems down the line, too. Why? Because lenses glued in with rigid setting glues such as super glue or epoxy may make the lens become a structural part of the frame, causing the lenses to chip or split during any sharp impacts with objects.

But if the frame and lenses are just for use as a spare pair, go ahead and glue the lenses in.

Do, however, consider using a 10-minute epoxy so you'll have time to clean up the sticky smears on the lenses before it sets completely.

A SOLDER SOLUTION

Last but not least, you can reduce the length of an eyewire by de-soldering the eyewire barrel and soldering it up just a bit, then cutting off the excess eyewire to reduce the circumference of the eyewire.

Of course, you should only do this if you can refinish the frame to its original appearance. And in some cases, that may not be easily achieved.

If the barrels are thick enough, you can file a barrel carefully in order to accomplish the same thing. Just don't get carried away to the point that the screw pulls through the barrel when you tighten it down. In otherwise, be careful.

Although the last few hints should be used only when needed, the knowledge of what it takes to hold a lens in should help you avoid those embarrassing moments that we all occasionally encounter.

Here is one more tip: Put a little lock tight or other screw locking goop on as you reassemble the frames. That just adds a little insurance, which is always good for peace of mind and for business!

Comments or questions may be addressed to the author at ayoho@mindspring.com.