The Mechanics of Fitting Glasses

7/27/2019 The Mechanics of Fitting Glasses

1/7

DefinitionsFrames: Fixtures that have rims going around the

lenses.Mountings: Fixtures that hold rimless lenses.Spectacles: Fixtures that are held in position by

means of bows (temples) t h ~ t go aronncl the side of thehenll and by a briclge that rC'sts on the crown of the nnse.When these have rims around the lenses they are knownas spectacle frames and when there are no rims aroundthe lenses they are known as spectacle mountings.

Eyeglasses: Fixtures that are held in position OILtIt n I'le by springs and by guards that press on the side/?of tll nose. With rims around the lenses they are eye-gin. frames and without rims they are eyeglassmountings.

SpectaclesTemples: Attachments on spectacles that go around

the .ide of the face and over the ears. Straight temples/0(0 Htraight back and do not circle the ears. Ridingj(,1l1pl cl'l (sometimes called riding bows) go entirelyII round the back of the ears. Half-riding temples are halfway Il tw en the straight temple and riding temple vari.,tim.;, jw:;t turning. lightly over the back of the ears.

gular T mples: The ordinary wire temples.Cllill 'r mple.: Made by wrapping two pieces of

plillhl{ wire :11)0111, oneil oth 1'.Ilnl f CallI e rl'('rtl pl eH: 'Ph part from the frame to

111(1 IOj) or 111/1 .. I r if.; of' the r eg illar' Hiff wir , the partII

Interesting to note the difference between spectacles and

eyeglasses (i.e., pince-nez); also the difference between

mountings and frames

"The Mechanics of Fitting Glasses"

Robert Pettet (1913)


2/7

II I ' l' I I I IJ MII;Cl l i \NICH Oil ' I"I ' I" I' IN(I (i1 , i\HHII; H

Spectacle Mount ing,goi ng around the ears is cable. There are several vari-eties of this kind: Comfort Temples, Apex Temples,Velvet End Temples, etc.; these are very similar in con-struction and differ only in the manner in which the softportion that encircles the ear is attached to the wire thatgoes to the frame. They are all very soft and pliable onthe ear end and are intended to increase the amount of

Spectacle Frame,comfort and eliminate the features of the regular wiretemples that tend to make the latter uncomfortable aboutthe ear.

Bridge: The part of a spectacle that rests on thenose and connects the two lenses. r:I.'his is the central andmost important portion of a spectacle.

Shanks: The ends of the bridge that point outwardfrom the nose and connect with the lenses.

Straps: The attachments at the end of the shanksand temples on rimlesB ~ ~ o u n t i n g s by means of which thelenses are held to the mounting.


3/7

THE MECHANICS OF FITTING GLASSES 11

End-pieces: The parts to which the temples are at-tached in rimless mountings; they include the strapswhich are really a part of them. When spoken of in con-nection with temples they are familiarly known as"ends," for instance, .we speak of "temples and ends."

Eye-wires: The rims that encircle the lenses onframes.

Eyeglasses (Regular) .

Eyegl ass Mounti ng. Eyeglass Frame.

Sv)'ing: rrhe central .part of the frame or mountingcorresponding to the bridge of spectacles. There are sev-eral styles of springs as shown by the illustrations givenhere. In addition to the different varieties there are dif-ferent sizes; the usual length of the oblong style is 21;8inches, and of the hoop style 2 inches. Oblong springs aresometimes called" square" springs and hoop springs aresometimes called "ovaL"Q Q

Oblong. Hoop. Full. Reduced.GRECIANQ I

i l t ing. Adjustable,

hoop springs are referred to as "regular eyeglasses"


4/7

01111 niH: 'rhe parts that lie agaillHt the sid 01' Ill('1l0He and hold to t l ~ e flesh; often called by the Jaity"clips. " By consulting catalogs of the wholesale opticalhouses it will be seen that there are countless styles anddesigns. A few of the most common are shown here.

)Wells. Lasso. Anchor. Schwab. Anatomical . Bausch. Solid.Studs: The parts that hold the lenses to the mounting and which join the guards and the spring.Open Studs: Those in which the nasal side of the

studs is left open.Box Studs: In these the portion into which theguard and spring fit is constructed like a box and the

nasal side is closed, the stud-screw is countersunk, andthus there are no rough parts or exposed screws in contact with the fle sh.

In addition to these two styles there are many sizes.that is, some have longer posts than others, the purposeof which is to regulate the distance between the lenses.There are also" drop" studs to lower the lenses; theseare made in two sizes-1-16 and 1-8 inch.

A B c o EFrom the illustration it will be observed that the

sizes of studs (controlled by the length of the post) are

superb examples of the various types of nose guards; note the

different sizes of studs


5/7


indicated by the letters A, B, C, D, E, and F; A being theshortest and F the longest, with about one millimeter be-tween each succeeding size.

Inset and Outset Studs: Confusion exists in themind of every beginner in the matter of inset and outsetstuds, and it must be admitted that there is good reasonfor this, and the beginner cannot be criticized for anymisunderstandings he may have in this regard, for thefact is there is so much difference of opinion in the mindsof various opticians and wholesale houses that it is neversafe to specify" inset" or "outset" until you know whatthe person or house to whom you are writing means bythese terms. Most wholesale catalogs state that insetstuds set the lenses farther from the eyes and that outsetstuds set the lenses closer to the eyes . To the mind of theaverage man who has not become accustomed to thistranslation of the terms they will seem to be reversed.'Where this usage of the terms originated was with theidea that inset studs set the mounting in toward the faceand consequently the lenses were set farther from theeyes, however when we realize that the mounting alwaysstays in the same position on the nose and it is the lenses

t h e m s e l v e ~ that are moved it would most certainly seemthat studs that set the lenses out should be termed" out-set, " but the term is not generally accepted this way, sothat the safest plan in writing prescriptions, etc., that youare sending away to be filled is always to st:ty "to set thelenses closer to the eyes" or "farther away," as may bewanted, for instance: "Inset studs, to set the lensesfarther from the eyes" or whatever way you want to putit, so that what you want will be clearly understood.


6/7

I I '1 111 1) Mllj,() II i \N ICH ()II' lo'i' l" I' I N(1 (:I ,i\SSIGH

Eyeglasses F i n g e r ~ P i e c e- .(Bridge: Same as the bridge in spectacles. This

usually includes the studs, as they are general1y made inone plece.

Finger-pieces: The projecting ends in front that aregrasped by the tips of the fingers in order to operate thespreading of the guards.

Springs: These connect directly with the guardsand cause them to press inward toward the nose.

Finger-piece eyeglasses are made in a great numberof styles and combinations and are given particular namet':by the various manufacturers. \iVhile eyeglasses of thisdesign appear at fir st sight to be very much alike, closeriRspection and study will show that there are severa lclassifications. This subj ect is discussed in another portion of this book under the heading "How to Judge aGood -Finger-piece Eyeglass Mounting."

Miscellaneous Frames and Mountings.Grab fronts are fixtures to contain lenses, usually the

addition for reading, which attach to the outside of spec-

tacles, and may be taken off and put on without removingthe spectacles proper. Grab fronts may be either with


7/7


rims or rimless. Grab backs are similar to grab frontsexcept that they attach to the back of the spectacles in-stead of the front.

Specalettes are a combination of eyeglasses andspectacles, that is they are eyeglasses with temples. These

are desirable where the patient has a straight and nearlyvertical nose and experiences difficulty in retaining aspectacle bridge in the proper position and in cases wheret.he skin on the front of the nose is very sensitive. There

are several forms of these mountings and catalogs ofwholesale optical houses should be consulted on thematter .

Documents

The Mechanics of Fitting Glasses