System for Ophthalmic Dispensing

665 Pages·2006·48.862 MB·English

by  Clifford W. Brooks, OD, and Irvin M. Borish, OD, DOS, LLD, DSc (Auth.)

11830 Westline Industrial Drive
St. Louis, Missouri 63146
SYSTEM FOR OPHTHALMIC DISPENSING, THIRD EDITION
ISBN-13: 978-0-7506-7480-5
ISBN-10: 0-7506-7480-6
Copyright © 2007 by Butterworth-Heinemann, an imprint of Elsevier Inc.
All rights reserved. No part of this publication may be reproduced or transmitted in any form or by
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Notice
Neither the Publisher nor the Authors assume any responsibility for any loss or injury and/or
damage to persons or property arising out of or related to any use of the material contained in
this book. It is the responsibility of the treating practitioner, relying on independent expertise and
knowledge of the patient, to determine the best treatment and method of application for the
patient.
The Publisher
Previous edition copyrighted 1996
ISBN-13: 978-0-7506-7480-5
ISBN-10: 0-7506-7480-6
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This book is dedicated to our students, whose interest and desire
to master the subject prompted its writing.
FM-H7480.indd v 8/1/2006 2:56:30 PM
Preface
The original goal for creating System for Ophthal- design. The second edition contained large numbers of
mic Dispensing was not to create a comprehensive photos—all in black and white. For the third edition the
textbook. Rather, we envisioned a student manual decision was made to start all over again, with color
to aid in the teaching of how to dispense prescription photos throughout. Hundreds of photos were taken,
eyewear. As the “manual” developed, Professional Press each from the point of view of the eye care provider.
learned of the project, expressed an interest, and There are major changes in the second half of the book
requested sample chapters. It became evident that such concerning ophthalmic lenses. All of these chapters have
a publication might be useful beyond the confi nes of been extensively reorganized and rewritten. Included are
teaching at Indiana University. large amounts of new material on progressive lenses,
Once a preliminary manuscript copy was available, it occupational progressive lenses, aspheric and atoric
was sent out for review. This resulted in a request for the lenses, and absorptive lenses. There are also two com-
addition of material on the optics of lenses. Thus the pletely new chapters—one on the optical aspects of anis-
second section of the book was added. Perhaps because eikonia, the other on how lenses are edged.
of the large number of photographs and illustrations, the All of these changes have been made in an attempt to
fi rst edition was found to be useful in both educational address the needs of two groups of professionals. The
programs and in ophthalmic practices. fi rst group consists of eye care providers who must stay
Ophthalmic dispensing of eyewear is basic through- current themselves, but also must individually train new
out the eye care world. And so is an understanding of personnel. The second group is made up of ophthalmic
how ophthalmic lenses perform. Both are essential for a educators and students in formalized educational pro-
new employee in an optical dispensary who is learning grams. Both groups need well-illustrated, comprehen-
on the job and for an experienced eye care practitioner. sive educational resources.
Knowing the varied backgrounds of the reading audi- The process of attempting to fulfi ll these needs has
ence, an attempt was made to write in a manner that been both time consuming and painstaking. You now see
would be understandable to someone new to the fi eld, the results. We hope that you will fi nd the new third
but would also include the type of information needed edition of System for Ophthalmic Dispensing to be infor-
by those with years of ophthalmic experience. mative, easy to use, and personally benefi cial.
The second edition built upon and updated the origi-
nal edition, adding sections on lens material and lens
vii
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Acknowledgments
For help in preparing the fi rst edition, the authors specifi c word of appreciation goes to Robert Woyton of
would especially like to thank Jacque Kubley for Hilco for reviewing the chapter on repairs and supplying
the original photography and many of the illustra- a number of photographs for both the second and third
tions; Sandra Corns Pickel and Sue Howard for serving editions.
as models; and Dr. Linda Dejmek, Kyu-Sun Rhee, Thanks to Ric Cradick of IU Photographic Services
Dennis Conway, and Steve Weiss for the artwork and for taking the multitude of new color photos for the
illustrations. For all the help received for the fi rst edition, third edition. His professional expertise is much
we continue to be very grateful. appreciated.
For the second edition, again thanks to Jacque Kubley To our students, we owe a debt of gratitude. They
for his continued assistance in photography and a number suffered through preliminary manuscripts, yet were
of the graphics. In the second and now the third edition, exceedingly helpful in pointing out omissions, making
thanks to Glenn Herringshaw, who manages Indiana valuable suggestions, and asking just the right questions.
University’s optical laboratory, for many helpful ideas Finally, special thanks to our many friends within the
and suggestions; and to Glenn and Regina Herringshaw profession for offering suggestions and supplying ideas
for serving as models for a number of the photographs. for improving the text. Without your advice and the
Also thanks to Pam Gondry and Dr. Eric Reinhard for information you provided, it would have been impossible
joining in the “modeling team” for the third edition. A to complete the task.
ix
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C H A P T E R 1
Frame Types and Parts
The purpose of this chapter is to acquaint the between the butt end and the bend is called the shank or
reader with the basic terminology used in shaft, and that portion beyond the bend and behind the
eyewear. This knowledge is essential to avoid ear is referred to as the earpiece, bent-down portion, or curl
misunderstanding the terms used later in the text to (Figure 1-2).
describe in detail the actual dispensing procedures.
BASIC PARTS CONSTRUCTION
Frames
The frame is that portion of the spectacles that holds the
lenses containing the ophthalmic prescription in their Frames without an eyewire going completely around the
proper position in front of the eyes. lens are called mountings. Lenses are “inserted” into
A frame generally consists of the front, which in one frames, but “mounted” into mountings. Frames them-
form or another contains the lenses, and the temples, selves can be classifi ed in a simplifi ed manner by one of
which attach to the front and hook over the ears to help the following categories of frames or mountings.
hold the spectacles in place. Frames occasionally do not
have temples and are instead held in place by pressure Plastic
on the sides of the nose (pince-nez), by attachment to Plastic frames are made of some type of plastic material.
another frame (clip-ons), or by being held in the hand Plastic frames were occasionally referred to as shell
(lorgnettes). frames, dating back to the time when eyeglass frames
were made of tortoise shell. This term has fallen into
Frame Fronts
disuse. Another general term that many still use for
That area of the frame front between the lenses that rests certain plastic frames is zyl, since at one time zylonite
on the nose is the bridge. The rim going around the (cellulose nitrate) was a commonly used material. Zylonite
lenses is known as the eyewire or rim. The outer areas of is highly fl ammable and no longer used for spectacle
the frame front, to the extreme left and right where the frames. The name “zyl” continues to be used, but usually
temples attach, are known as the endpieces. A few plastic refers to the most commonly used plastic material-
frames may still have a metal shield on the front of the cellulose acetate. Now, with the emergence of many new
endpiece to which rivets are attached to hold the hinge materials, either the exact name of the plastic material
in place (Figure 1-1). is used or the frame is simply referred to as plastic
The hinges hold the temples to the front, and consist (Figure 1-3).
of an odd number of interfi tting barrels, the total number
being three, fi ve, or seven. Hinges may vary in construc- Metal
tion, but for simplicity are usually classifi ed by the total Metal frames are those made of all metal parts, except for
number of barrels they have when assembled, such as a the nose pads and the posterior temple sections, which
three-barrel hinge. are plastic covered. The eyewire runs completely around
Some frames have nose pads, which are plastic pieces the lens (Figure 1-4).
that rest on the nose to support the frame. These may
be directly attached to the frame or to connecting metal Nylon cord frames
pieces known as guard arms or pad arms. Nylon cord frames, sometimes called string mounted frames
or nylon supras hold the lenses in place by means of a
Temples
nylon cord that fi ts around the edge of the lens. This
The portion of the temple that is nearest its attachment gives the glasses the appearance of being rimless. Usually
to the front is known as the butt portion or butt end. The the top of the lens is fi tted into the upper rim of the
place on the temple where it fi rst bends down to go over frames. The rest of the lens has a small groove cut into
the ear is called the bend. The portion of the temple an otherwise fl at edge (Figure 1-5).
3
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4 Ophthalmic Dispensing PART ONE
Combination frame with plastic eye-wires and metal bridge and
Combination frames are commonly frames having a metal temples.
chassis and plastic top rims and temples (Figure 1-6). The
chassis includes the eyewire and center or bridge section. Half-eye
Although this is the most common construction, techni- Half-eyes are frames made especially for those who need
cally any frame with a combination of metal and plastic a reading correction but no correction for distance. They
could be included in this category, as in the case of a are constructed to sit lower on the nose than normal,
and are only half as high as normal glasses. This allows
the wearer to look over the top of the glasses. They may
Bridge Shield be of plastic, metal, or even nylon cord construction
Endpiece
(Figure 1-7). Less common are half-eyes for distant
vision, which allow the wearer to look under the lenses
for reading.
Rimless, Semirimless, and Numont
Nosepad Rimless mountings hold the lenses in place by some method
other than eyewires or nylon cords. Often screws are
Eyewire or rim used, but cement, clamps, and plastic posts have been
Figure 1-1. The frame front. used. Most rimless mountings have two areas of attach-
ment per lens, one nasally and one temporally (Figure
1-8). Rimless mountings are sometimes referred to as
Butt portion
3-piece mountings.
Shaft (shank) Semirimless mountings are similar to the rimless except
Bend for a metal reinforcing arm, which follows the upper
posterior surface of the lens and joins the centerpiece of
Dowel the frame to the endpiece. The centerpiece of a mount-
Shield
hole ing consists of bridge, pad arms, and pads (Figure 1-9).
E
ar Numont mountings hold the lenses in place only at
pi
e
c their nasal edge. They are seldom seen today. The lenses
e
D.J.C are attached at the bridge area and the temples are
Figure 1-2. Parts of a temple. attached to a metal arm that extends along the posterior
Figure 1-3. An example of a plastic frame.
Figure 1-4. One version of a metal frame.
Ch001-H7480.indd 4 7/27/2006 5:25:59 PM
CHAPTER 1 Frame Types and Parts 5
Figure 1-5. A nylon cord frame or “string mount” holds the lens in place with a cord that
fi ts around the edge of the grooved lens.
Figure 1-6. Examples of combination frames.
Figure 1-7. Half-eye frames in use. Half-eyes are made especially for those who need a
reading correction but no correction for distance vision.
Figure 1-8. An example of a rimless mounting. The central area of the frame is not connected
to the endpieces. The only connecting points are the lenses themselves.
Ch001-H7480.indd 5 7/27/2006 5:26:00 PM
6 Ophthalmic Dispensing PART ONE
Figure 1-9. A semirimless mounting has a bar behind the top
of the lens connecting the endpieces to the bridge area.
A
Figure 1-10. A Numont mounting has only one nasal point
of attachment per lens.
surface temporally. Thus there is only one point of
attachment per lens (Figure 1-10). B
Currently most dispensers refer to any of these three Figure 1-11. A balgrip mounting. In this form of rimless
variations of a rimless mounting as “rimless.” They do mounting, the slotted lenses (A) are held in place with clips
not differentiate between the three. (B).
Other Mountings
Balgrip mountings secure the lens in place with clips there is also quite an assortment of bridge constructions
attached to a bar of tensile steel that fi ts into a nasal and in both materials.
a temporal notch on each side of the lens. The lens can
be easily removed by pulling the clips back from the lens. Plastic Bridges
For this reason, this type of mounting can be used with The bridge area of a plastic frame is preformed and sits
more than one pair of lenses for the same frame. Sun- directly on the bridge of the nose. It is important, then,
lenses, special purpose lenses, or tinted lenses could then in picking out a plastic frame that the frame fi t the nose
be used interchangeably with the patient’s regular lenses well, since adjustments to this part of the frame are
(Figure 1-11). Notches are now more often used in com- extremely diffi cult. Bridge adjustments for certain plas-
bination with drilled holes in rimless mountings to lend tics, such as nylon, carbon fi ber and polyamide, are not
stability to the mounting. possible.
The saddle bridge is shaped like a saddle in a smooth
Bridge Area
curve and follows the bridge of the nose (Figure 1-12).
The bridge area of a frame can be constructed of either This spreads the weight of the frame evenly over the
plastic or metal. Because of the variety of nose shapes, sides and crest of the nose.
Ch001-H7480.indd 6 7/27/2006 5:26:02 PM
CHAPTER 1 Frame Types and Parts 7
Figure 1-12. The saddle bridge closely follows the contour of
the nose, evenly spreading the weight of the frame.
Figure 1-14. Besides having an identifying shape, the keyhole
bridge supports the frame weight upon pads.
Figure 1-15. Metal saddle bridges were originally designed to
rest directly on the crest of the nose. They may still be used
as originally designed shown in the frame pictured. Often a
Figure 1-13. The modifi ed saddle bridge has fi xed nose pads metal saddle bridge is just for decorative purposes and is used
attached at the back to increase the weight-bearing area of the in conjunction with nosepads.
frame.
Metal and rimless frames were, and sometimes still
In the modifi ed saddle, the bridge area looks much the are, constructed with a metal saddle bridge∗ (Figure 1-15)
same as the saddle bridge does when viewed from the
and enjoyed widespread use for a period of history. It
front. The difference is that there are nose pads that are
may yet appear exactly as before or decoratively in con-
part of the back of the bridge. These pads help to carry
junction with nosepads.
some of the weight of the frame (Figure 1-13).
With rimless mountings, the crest of the bridge does
The keyhole bridge is shaped like an old-fashioned
not include the pads or straps, but is the center most
keyhole. At the top, the bridge fl ares out slightly. The
area.
bridge rests on the sides of the nose, but not on the crest
(Figure 1-14). Endpiece Construction
Endpiece construction, like the bridge area construc-
Metal Bridges
tion, can be of either plastic or metal.
The bridge commonly used in metal frames is the pad
bridge (see Figure 1-8). In the pad bridge, nose pads are
Plastic Endpieces Construction
attached to the frame by metal pad arms. In this case,
There are three general types of endpiece construction
the pads alone support the weight of the glasses.
in plastic frames (Figure 1-16). The most common
When a metal frame is equipped with a clear plastic
saddle-type bridge, the bridge type is referred to as a
comfort bridge. *Historically the metal saddle bridge was called a W bridge.
Ch001-H7480.indd 7 7/27/2006 5:26:05 PM
8 Ophthalmic Dispensing PART ONE
A
B
Figure 1-17. This traditional metal endpiece has a turn-back
design.
C
Figure 1-16. Endpieces of plastic frames classifi ed as mitre
(A), butt (B), and turn-back (C).
endpiece construction is the butt type, in which the front
is straight and the temple butt is fl at, and both meet at
a 90-degree angle. The mitre endpiece causes the frame
front contact area and temple butt to meet at a 45-degree Figure 1-18. Some metal endpieces are not really endpieces
angle. In the turn-back type, the frame front bends at all. The endpiece and temple are one continuous piece of
around and meets the temple end to end. material as in this “wrap” endpiece design.
Metal Endpiece Construction
Temple Construction
The traditional metal endpiece has a construction similar
to the turn-back endpiece of the plastic frame (Figure Temples also vary greatly in their construction. In
1-17). There are now a wide variety of metal endpiece general, there are fi ve major categories (Figure 1-19).
designs. 1. Skull temples bend down behind the ear and follow
Endpieces are also noticeable by their absence. Instead the contour of the skull, resting evenly against it.
of an endpiece, some frame fronts and temples are made The bent-down portion is narrower at the top of the
as one continuous piece (Figure 1-18). ear and widens toward the end.
Ch001-H7480.indd 8 7/27/2006 5:26:07 PM