Fix and Fit
Back in Plastic
By Alex Yoho, ABOM

It's like we are entering the 1960s all over again--small dark plastic frames and beautiful laminates are just the right touch for that funky retro look your patients are going for. The problem is, the experts who once dealt with these types of frames have for the most part retired, leaving behind a generation of opticians who have little or no experience with the special requirements for this category.

In part one of this Fix & Fit series, we will examine what you need to understand to fit plastic frames on the face and provide helpful tips for making adjustments just like an old pro.

The process of heating frames, letting them sit, and re-heating them can create the correct conditions for making adjustments to plastic frames. When adapting the bridge, make a heap of beads in the center of the heater for on-target warming to make the inside of the bridge hotter than the outside

BUILDING BRIDGES

The first thing you'll notice as you begin to bring plastic frames (often referred to as zyl) into your repertoire is that the bridges don't fit many people. This is especially true of the long narrow shapes that are so trendy at this writing.

The first thing to strive for when selecting a frame is a bridge that offers the most contact to disperse the weight over the greatest possible area. On a fixed bridge, a saddle type offers the best comfort since the nose is touched on the top and sides.

If this isn't possible, the next best thing is to have the sides touch as much as possible--if the frame rests only on the crest of the nose, the patient will often end up with a red spot there.

Now you might think that if the frame doesn't fit in the bridge, a different frame should be selected. Don't be so hasty. Many plastic frames can be modified in the bridge area.

The first thing to consider is the frontal angle. If the angle is the same as the nose, but the bridge doesn't rest on the crest of the nose, you may want to widen it to allow better contact area. This can be accomplished by heating the bridge and pulling the frame from both sides. The thicker the bridge, the more you'll be able to widen it.

With today's materials, it may not be wise to stretch a bridge more than a half to one millimeter at the most. If the frame is marked cold mount or you know it is polyamide or propionate, it will not stretch more than a half millimeter or so. Though cellulose acetate frames are one of the older types used, they are the best for customizing.

If the sides of the frame are an even angle with the nose, but rest solely on the crest of the nose without touching the sides, you should narrow the bridge. Again, cellulose acetate frames are far superior when it comes to custom narrowing a bridge.

The best technique I have used so far is to heat the bridge in a manner that makes the inside plastic of the bridge hotter than the outside. To accomplish this try the following:

	When working with plastics, eyecare practitioners frequently find that the bridges don't fit patients correctly. With a little heating and adjustment, this can be fixed

Targeted heat. Use a bead or salt pan and heap the particles up in the middle so when the frame is moved back and forth, only the bridge is heated. It is best to leave the lenses in the frame. But, be aware that a good number of lens materials and treatments are heat sensitive, so avoid heating them too much.

Repeat. Heat the bridge in this manner several times until quite hot, then set it on the table for about 10 to 15 seconds. Then re-heat the frame one more time.

Wait and compress. Now wait for about eight seconds, then begin to push the lenses closer together to compress the bridge. This will thicken the bridge up, but be very careful not to change the frame's frontal angle.

The reason behind the reheating of the bridge and letting it cool is to make the outer skin of the bridge cooler than the center so when you compress the bridge, the soft center bulges out in a uniform way and tends not to wrinkle the surface.

This is quite important, as a wrinkle creates a weak point that will allow the frame to crack much sooner. In fact, this is so critical that if a wrinkle does occur, it should be filed out, sanded, and buffed to its original luster.

COOL ANGLES

Next, there's the situation where the frontal angle of the bridge is not equal to the angle of the nose. In this instance we would heat the nasal area of the frame and either bend in a nasal fill or a nasal cut, being careful not to distort the rest of the frame.

These changes used to be done by edging the lenses larger than normal, then removing stock from the upper nasal area to leave the lower portion to fill in the nasal area for noses with a very straight up and down angle. Or, it was done to cut away some of the lower nasal area which causes the frame to draw away from the nose at the bottom for those noses that flair out rapidly from top to bottom.

Now that frames are normally traced individually to process, it's generally easier to shape the nasal part of the frame. We can try it on the patient and, after it's traced and edged, it will fit just as it did on your patient.

One of the handiest tools for making this adjustment is a wooden dowel or piece of a broom handle. After heating the nasal area of the frame, use the dowel to gently shape the nasal portion in toward the nose using an up and down stroke to blend it in. Putting an outright lump in the nasal eyewire is impractical since most edgers are incapable of following such drastic curves.

GROOVY PADS

There is also the wonderful availability of adjustable pad arms for plastic frames, which can be put on all but the ultra- thin frames. Even then you can sometimes file the prongs thinner and insert them.

One tool for this is Hilco's "Hot Fingers." This device is basically a pair of electric tweezers that heats up metal parts that are held in the tips of the tool.

The only disadvantage is that you have to remove any back pads, which is done by clipping the majority off with a sharp pair of cutters, then filing the remainder flush to the rest of the frame, sanding smooth, and finally polishing. The final result can be a huge benefit to your patients.

Hopefully, this primer will help you and your co-workers address these new-old frames as they evolve yet again.

In the next Fix and Fit, brush up on mounting lenses and fitting temples in these blast-from-the-past plastics.

Your comments or questions may be addressed to the author at ayoho@cox.net.