As an optical laboratory employee you may be responsible for maintaining the level of stock required by your laboratory for each type of frame that you keep. To do so you have to know how to identify each item. In this unit you will learn about the frame materials, basic parts of a frame, different types of frames, and the storage of frames in the laboratory.

Some General Information

One of the challenges you will face when you are locating a frame for your customer has to do with the large number of frames available. You will have to be sure that you get the right one. The best way to do this is to be sure you check the following frame information: the manufacturer, style number, style name, color, eye size, bridge and temple length. There are hundreds of new frame styles coming out each year and it is impossible for any person to expect to keep the details about each new frame in mind. And since many of those frames differ only slightly, you probably won't always be able to tell by sight if you have the correct frame. So don't be in too much of a hurry as you are picking the frames. Remember, time taken at this step in the process is better spent than the time and money lost if you were to have the laboratory place a patient's prescription into the wrong frame.

Frames may be stored in the stockroom in a variety of ways. In fact, each laboratory has its own special variation on the system. But most often there is a large collection of frame cabinets, with many small cubbyholes holding the frames. You will find one type, color, style and size of frame per cubbyhole.

In large laboratories, there may be automatic filing systems, sometimes referred to as "Lektrievers." The cubbyholes are shelves which rotate when buttons are pushed. The Lektriever is tall, often rising as high as the ceiling, and allows for more effective use of space in the lab.

Frame Materials

Today's frames are made of many different types of materials. Different materials are used for style, durability, color, and ease of use but, for the most part, frames are made from plastic and metal.

Plastic frames are available in many colors and are usually thicker and wider than metal frames. Metal frames tend to be thinner, lightweight, and strong. Each material has features that make it popular.

Some of the different types of plastic and metal frames, and their characteristics, are:

Cellulose Acetate

• Light

" Easy to work with

" Available in many colors and styles

Propionate

" Light

" Hypoallergenic

" Delicate material

Nylon

" Very durable

" Used for sports

" Limited colors

Titanium

" Strong

" Light

" Hypoallergenic

Stainless Steel

" Strong

" Light

" Thin profile

Nickel Monet

" Easy to work with

" Pliable

" Won't fracture

Basic Frame Parts

Most ophthalmic frames are made up from three parts: the front, a left temple, and a right temple (see Figure 6-1). The combination frame, which you will study later, may also be made up from a front, called a chassis, to which trim plaques can be added.

Figure 6-1 Parts of a Basic Ophthalmic Frame

Some temples are exchangeable with different front sizes and, occasionally, with different front styles. Therefore, frames with interchangeable fronts and temples are stocked separately. The frames are assembled by shop personnel as part of the manufacturing procedure. There is an increasing trend among manufacturers to supply completely assembled frames.

The Bridge

The bridge of the frame front serves two functions. First, it sup-ports the glasses on the nose. Second, it connects the two lens containers. The front holds the lenses in a precise orientation before the patient's eye according to the prescription.

Bridge Types

There are several ways to rest the front of the glasses on the nose. Adjustable rocking nose pads may be attached to the bridge. A special bridge insert of molded plastic, sometimes known as a form-fit bridge, may also be used. Finally, the bridge and nose rest area may be integrally molded into the frame. The latter technique is used for most plastic frames. The bridge in plastic frames may be further classified into the keyhole bridge and the saddle style bridge. Figure 6-2 shows a picture of a keyhole bridge. It is called that because it looks something like the keyhole in an old door. The bridge contour is not continuous; it has small cut-out sections on either side. This means that the nose does not make continuous contact with the front of the frame in the area called the nasal crest.

Figure 6-2 A Frame with a Keyhole Bridge



Figure 6-3 A Frame with a Saddle Bridge

The saddle bridge, shown in Figure 6-3, is also common. It allows the nose to make continuous contact with the front of the frame.

Each frame has openings (or apertures) for two lenses — a right lens and a left lens. The left lens is the opening on the wearer's left. The opening for the right lens is the opening on the wearer's right. Refer back to the illustration in Figure 6-1.

The temple of the frame is the long portion that supports the frame on the ears. It is also known as the earpiece. There are a variety of different styles of temples. We will discuss three of the most common ones in this course. Figure 6-4 shows the three basic types of temple used on eyeglasses.

Note: The overall length that you will find marked on the temple is actually the unbent length that you see in Figure 6-4.

Figure 6-4 Three Basic Temple Styles

Temple length is now measured in millimeters, but it used to be measured in inches. Therefore, you may occasionally have to convert a measure from inches to millimeters. Figure 6-5 shows a conversion scale which you may find helpful.

Figure 6-5 Conversion Scale Inches to Millimeters
Note: Due to Monitor and Printer Variations this scale may appear different as intended

Library Temple

The library temple has almost no bend over the ear. Look again at Figure 6-4. This type of temple was developed for people who need to remove and replace their glasses many times during the day, such as someone doing research in a library, and that seems to be the origin of the name.

Skull Temple

The most common type of temple is called the skull temple. The bent and unbent versions of the skull temple are shown in Figure 6-4. Look again at that figure before proceeding with this section. The skull temple is most comfortable for those people who wear their eyeglasses for long periods of time. It fits easily on the ear, and bends slightly to fit the skull and lightly hug the head. Figure 6-6 shows a picture of a frame with skull temples.

Figure 6-6 Frame with Skull Temples

Riding/Cable Bow Temple

The third type of temple we'll consider in this course is the riding or cable bow temple. As you can see by looking at Figures 6-4 and 6-7, this type of temple fits around the ear. It hugs the ear, and is more difficult to remove. This type of temple would be particularly helpful for those people whose jobs are very active, or for children who are likely to romp and play with little thought for their eye-glasses.

Figure 6-7 Frame with Riding Bow Temple

Hardware

There are a few pieces of hardware found on the frame: hinges and temple screws. A hinge is a frame component consisting of three main parts: the two halves of the hinge barrel and a pivot pin or screw. One barrel half is mounted in the frame front, the other mating barrel half is mounted in the temple piece. The pivot pin or screw secures the two halves of the hinge barrel together. The hinges permit the temples to fold easily.

Plastic temples on many types of frames have a wire which runs horizontally through the middle. This core wire has been added for strength.

There are many different types of frames. We will study five different types in this course. The variations in type are based on the materials from which the frames are made, their style, and the purpose for which the frames are designed.

Plastic Frames

For years, the most common frames were made from a cellulose acetate material called zyl. Recently, new plastic materials have been utilized in frame manufacture. Each has unique properties that enhance fabrication, safety, or colorization. These materials include epoxies, propionates and nylons. Each requires different handling in the finish room.

Metal Frames

With metal frames, the temples and front are made of metal, except the portion of the temple that fits the skull. Figure 6-8 shows a metal frame. Note that this metal frame is equipped with adjustable rocking nose pads.

Figure 6-8 Metal Frame

Rimless Frames

There are some frames which provide no, or only partial, peripheral support for the lenses. These are called rimless, or semi-rimless, frames. Rimless frames are constructed in several different ways. Figure 6-9 shows one type of rimless frame in which tiny screws have been inserted through the eyeglass lens to attach the frame.

Another style that has become very popular requires a shallow groove to be cut into the edge of the lenses into which a nylon cord fits. Each end of the nylon cord is attached to the frame. The tension in the nylon holds the lenses firmly in the mounting.

Some frames are made from a variety of materials and decorative parts. These frames are called combination frames.

Figure 6-10 Combination Frame

The combination frame shown in Figure 6-10 is composed of five parts. The lenses are contained in a metal chassis; two trim over-lays are added to the chassis and metal or zyl temples are hinged to the top rims. This frame uses adjustable rocking nose pads for support.

The halfeye, or reading eyeglasses (see Figure 6-11), are only half lenses, so that the presbyopic emmetrope can focus on things at a distance by looking over the lens without having to remove their eyeglasses. Although they are less common, there are also frames designed for the presbyopic myope to look under lenses that possess their distance correction. This individual needs little, if any, correction for reading, but must look through their correction to see distant objects clearly.

Figure 6-11 The Halfeye Frame