What to Know before you buy

Your optician can advise you on the benefits and/or disadvantages of plastic or glass lenses. Your lifestyle or job may dictate the choice of one over the other for you. You may have a personal preference for one or the other. Many new advancements in lens technology have made plastic lenses potentially thinner, lighter, and very scratch resistant. Glass remains the standard for safety applications and has the ability to adapt to differing light conditions, as do some plastic lenses now. Again, the choices are varied and your individual needs should be discussed with your dispenser before you buy. As in any purchase, you are entitled to information, and if you can not get it, go somewhere else. There are many eye care professionals out there, find one you can be comfortable with.

The intent of this article is not to choose a frame for you, but to help you choose a frame that will stand up to your use. Your first decision is whether to go with a plastic or metal frame. There are many kinds of both plastic and metal frames. The choice between a plastic or a metal frame depends on many factors. Some people can not wear plastic frames because of the shape of their nose, or they can not get the correct adjustment; others can not wear metal frames due to the same reasons, or perhaps their skin reacts with metal in close contact. There are hundreds of reasons for or against each type of frame, and that is one reason why there are so many styles available to choose from. From twenty years of experience exclusively repairing eyeglass frames, I can assure you that though a frame or its material may be advertised as unbreakable, IT ISN'T! Many of the"unbreakable" frames are made of reliable material, but when broken, they are not repairable by any process-so the buyer is stuck with purchasing a new frame. Often the frame has been discontinued and the buyer must then purchase a new frame and new lenses.

PLASTICS FRAMES:
There are many types of plastics used in eyeglass frames today. All of them are tough, and usually more than adequate for the job they were designed for. Occasionally a designer will force a manufacturer to produce a frame that calls for more than the material can deliver. Those frames usually do not stay on the market long. Far and away the most common plastic used in frames is zyl. It has been around for many years and frames made of this material are repairable. Zyl plastic will dry out after several years. When it does it begins to "check crack", and it becomes brittle. Eventually one of the check cracks will break through. Optyl® a, registered trademark of the Optyl Corporation, has also been around for many years. It is a tough, but non repairable plastic. While somewhat flexible, it can not be adjusted (bent) at all while cold or it will snap. The frame retains the adjustment it was given when originally heated and fitted unless reheated. It rarely dries out and becomes brittle Most frames made of this material can be identified by the trademark stamped on the inside of the temple, or by the phrase "Frame Austria", "Frame Germany" , or "Frame Canada" stamped in the same place. Many designer frames are made of this material.
Another type of plastic used in frames is carbon fiber. It is strong and light weight, and some manufacturers have taken its use to extremes Many frames made of carbon fiber on the market today are not repairable because the frame is just too thin. Many improvements have been made to these frames such as metal temples and hinges, threaded metal inserts for the screws and the placement of more material at critical stress points. If I was going to buy a frame made of carbon fiber I would ask about the availability of parts, and how long a design from that particular manufacturer stays on the market. These are appropriate questions to ask before the purchase of any frame. the Dupont Corporation has long been a leader in the introduction of new plastics designed for specific uses. There are some frame manufacturers beginning to use some of these plastics. Only time will tell if the frames repairable, and how they stand up to use. Ask your dispenser before you buy. Nylon is another material that has been around a long time. It is used mainly in sport frames. Frames made of nylon are repairable and tough, but should be soaked in water once a week to maintain their strength. There are hundreds of other types of plastic , and at one time or another most of them have been or will be used to make eyeglass frames. (Talk to your dispenser and find out what the track record of the plastic frame you are considering is. ) If you have to be the first to have a new product or style you may have to be willing to accept the consequences of an inadequate design or material.

METAL FRAMES:
Very few frames have any gold at all in them. Most metal frames start out as an alloy of nickel and silver. Some manufacture's have fancy names, or exclusive layering processes using some rarer metals. Many frames are now being made of titanium . Some are also being made of stainless steel Sometimes aluminum is used, but not often. The basic frame metal goes through a variety of possible processes,. It may be painted, plated various colors (gold, Silver, copper, pewter , black , etc . ) lacquered, or just polished The manufacturers are constantly working on one style or another to keep up with each other.
Aluminum is very difficult to repair, and is difficult to make the frame look like new when it is. Titanium frames are usually very expensive, and they do break. Most have a good warranty, but get it in writing. If they break they need a very special TIG welding process that may or may not be able to repair them. Even if you are able to find someone who repairs frames in your town they may not have the equipment or ability to repair titanium . Aluminum and titanium are good materials and will give good service, as long as they do not need to be repaired.
Stainless steel and nickel-silver frames are by far the most common. Both types are relatively easily repaired by silver brazing, and the repairs can look like or almost like new. Strength wise the repair may exceed the original frame as it was manufactured. How a repair looks on a metal frame is not indicative of how much the frame cost initially. I have seen some ten dollar sunglasses look better than a very expensive designer metal frame after a repair. Unless the frame is an older style with some gold in it or the frame is a silver color the repair will show to some extent. Even if gold solder is used the gold color on newer frames will be burnt off . Silver or pewter colored frames look the best after a repair. Metal frames that are painted, lacquered, plated colors other than silver or pewter, or ones that have plastic color inserts applied to the metal will show when brazed. Many times the color can be approximated with paint. The paint will not wear as well as the factory applied finish however.
Metal frames have three basic types of support for the nose. The individual pad arm, the one piece plastic insert pad, and the non-adjustable plastic pads that are mounted by various means to the eyewire on either side of the nose. There are still a few frames that have no support for the nose at all and allow the metal bridge to rest directly on the nose. The individual pad arm allows the most freedom in adjustment, and many sizes of pad are available. Several types of material, such as hard plastic or silicone rubber are used in making the pads . This flexibility can make it possible to fit almost everyone. Silicone pads do tear easily, but they can help keep a frame from slipping. Make sure that you can get a different style of pad put on the frame if you decide at a later date you do not like the kind the frame came with. (This applies only to frames with individual pad arms. ) One of the disadvantages to this type of support is the freedom of adjustment-it can get out of adjustment if the frame is subjected to abuse or hard treatment. All of the above applies to plastic frames that have adjustable pad arms or had them added later. The one-piece plastic pad or silicone can be mounted either with screws on each side or through the middle or with just. a "snap in" fit. . These methods work well most of the time. Screws work loose, and a "snap in" pad will also snap out if abused. This type of pad is either in adjustment or broken, So if you purchase one of these make sure that it fits your nose. The pad should press uniformly on both sides of your nose as well as on the top. The pad is designed t.o spread the weight all over the bridge. If it fits right it will be very comfortable, if it puts pressure on one point it will be very hard to live with. Most of the pads can not be adjusted. Sometimes they can be ground off or built up but the results are rarely" satisfactory. One thing I would consider if I purchased a frame with any type of one piece pad would be to buy several extra pads right then. These pads do not usually break , but by the time you need a new one they may not be available. If you break the pad you may have to buy a new frame and lenses too, or have individual pad arms brazed on. In some instances you can find some other style of pad that can be ground and made to f it in .
Lastly, unlike the adjustable pad arms some frames have individual plastic or silicone pads mounted directly to the metal or plastic eyewear that holds the lens in. As a result they do not work out of adjustment Check the fit of each pad on the side if the nose if the frame does not fit it never will . Again buy extra pads when you purchase the frame for all the reasons that were listed for one piece plastic pads.
IN CLOSING:
What else should you look for when purchasing a metal frame? I would look for one very heavy (strong) bridge over the nose, or two that are not too thin. They should-be thicker than a toothpick. The hinges on the temples (bows, stems, handles, etc. ) should not be too thin. These hinges come in many styles, and have three, five, or even -seven leaves. The three leaf-hinge system, (two on-one side and one on the other) is generally the weakest system made. Make sure that each leaf is thick enough, i.e at least as thick as four layers of a matchbook cover per leaf.. If they are any thinner they will be prone to breakage. Most of the five and seven leaf hinge systems are sturdy enough under normal use. Many frames (both plastic and metal) now come with springs in the temple hinge to aid in adjustment and durability. These hinges work well, but again look for a pair of frames with substantially thick hinge leaves.
In general the same standards apply for a plastic frame as far as bridges and hinges. Here are some other things to look for or ask about when purchasing either type of frame. Ask if the frame has been discontinued. Discontinued frames are usually sold at a discount. Though most frames are not offered for sale more than a year before they are discontinued, a discontinued frame may be a good buy if it meets the other standards discussed here. Ask if you can purchase individual -parts such as temples, the front (the part that holds the lenses), pads, etc. If you, break a part and do not want to wear a repaired frame and can not buy new parts, then you will have to buy a whole new frame. Have the dispenser check to be sure that the temples are long enough, or not too long, to fit you properly. The amount of temple behind your ear should be about one and one-half to two inches. If you want cable temples, ones that are very flexible like springs behind your ear, be prepared to take some time to get adjusted to them. Also check the length on them. If you are purchasing a frame with a fixed one piece plastic bridge, or a plastic frame without individual pad arms (they can be added later to most plastic frames) make sure that the bridge does fit correctly. Ideally it should rest some of the weight over all of your nose's bridge, not just on the sides. Again, some plastic frames now have silicone pad inserts on the bridge to help stop slipping of heavy lens/frame choices, but remember the weight will be concentrated where the pads are. If you are purchasing a frame that will have large lenses in it, the lenses will be heavy; consider-plastic lenses- which are lighter. When purchasing frames for children, take their likes into consideration too. If you buy them frames they do not like they may not wear the glasses or they may not take good care of them. If you take your grasses on and off a lot try to do it with both hands as this puts less stress on the frame.- If you carry your glasses around in a purse, briefcase, etc. try to use a hard case rather that the soft slip in case you are given at most optical shops. The hard case will take the abuse rather than the frame-the abuse you never realize you are giving the frame when it is in a case. A repair on- a metal frame will almost always be as strong as new but it will almost always show. If you break a repairable plastic the repair will show too but it will not be as strong as new. Hinges repaired on plastic frames are as good as new in almost all cases.