Transcriber’s Notes:
Underscores “_” before and after a word or phrase indicate _italics_
in the original text.
Small capitals have been converted to SOLID capitals.
Illustrations have been moved so they do not break up paragraphs.
[Illustration: =SKI-OPTOMETER MASTER MODEL 215=
Embodying in a Single Instrument, in Convenient Form,
Cylindrical and Spherical Lenses, in Combination
with Appliances for Testing and Correcting
Muscular Imbalance.]
Refraction and
Muscular Imbalance
_As Simplified Through the Use
of the Ski-optometer_
By
DANIEL WOOLF
WOOLF INSTRUMENT CORPORATION
NEW YORK: 516 FIFTH AVENUE
Copyright 1921
By WOOLF INSTRUMENT CORPORATION
Published by
THEODORE S. HOLBROOK
NEW YORK
CONTENTS
CHAPTER I Page
SKI-OPTOMETER CONSTRUCTION 1
Convex Spherical Lenses 2
Operates and Indicates Automatically 6
Concave Spherical Lenses 7
CHAPTER II
CYLINDRICAL LENSES 10
Obtaining Correct Focus 11
Why Concave Cylinders Are Used Exclusively 14
Transposition of Lenses 14
CHAPTER III
HOW THE SKI-OPTOMETER ASSISTS IN REFRACTION 17
The Use of the Ski-optometer in Skioscopy 17
A Simplified Skioscopic Method 20
Employing Spheres and Cylinders in Skioscopy 22
Use of the Ski-optometer in Subjective Testing 23
A Simplified Subjective Method 24
Procedure for Using Minus Cylinders Exclusively 26
Constant Attention Not Required 29
CHAPTER IV
IMPORTANT POINTS IN CONNECTION WITH THE
USE OF THE SKI-OPTOMETER 30
Elimination of Trial-Frame Discomfort 30
Rigidity of Construction 31
How to Place the Ski-optometer in Position 32
Cleaning the Lenses 33
Accuracy Assured in Every Test 34
Built to Last a Lifetime 35
CHAPTER V
CONDENSED PROCEDURE FOR MAKING SPHERE AND
CYLINDER TEST WITH THE SKI-OPTOMETER 37
Subjective Distance Test 37
Subjective Reading Test 40
CHAPTER VI
MUSCULAR IMBALANCE 41
The Action of Prisms 42
The Phorometer 43
The Maddox Rod 44
Procedure for Making the Muscle Test 45
Binocular and Monocular Test 47
CHAPTER VII
THE BINOCULAR MUSCLE TEST 48
Made with the Maddox Rod and Phorometer 48
Esophoria and Exophoria 50
Making Muscle Test Before and After
Optical Correction 52
When to Consider Correction of Muscular Imbalance 53
Four Methods for Correction of Muscular Imbalance 54
The Rotary Prism 54
Use of the Rotary Prism in Binocular Muscle Tests 56
CHAPTER VIII
THE MONOCULAR DUCTION MUSCLE TEST 58
Made with Both Rotary Prisms 58
Locating the Faulty Muscle 58
Adduction 59
Abduction 61
Superduction 62
Subduction 63
Procedure for Monocular Muscle Testing 64
Diagnosing a Specific Muscle Case 65
CHAPTER IX
FIRST METHOD OF TREATMENT—OPTICAL CORRECTION 70
Esophoria 70
Treatment for Correcting Esophoria in Children 72
How Optical Correction Tends to Decrease 6°
Esophoria in a Child 74
CHAPTER X
SECOND METHOD OF TREATMENT—MUSCULAR EXERCISE 75
Made with Two Rotary Prisms and Red Maddox Rod 75
Exophoria 75
An Assumed Case 78
Effect of Muscular Exercise 80
Home Treatment for Muscular Exercise—Square Prism
Set Used in Conjunction with the Ski-optometer 82
CHAPTER XI
THIRD METHOD OF TREATMENT—PRISM LENSES 84
When and How Employed 84
Prism Reduction Method 85
CHAPTER XII
A CONDENSATION OF PREVIOUS CHAPTERS ON THE PROCEDURE
FOR MUSCLE TESTING WITH THE SKI-OPTOMETER 87
Four Methods of Treating an Imbalance Case
when the Preceding One Fails 90
Prisms 92
Cyclophoria 92
CHAPTER XIII
CYCLOPHORIA 93
Made with Maddox Rods and Rotary Prisms 93
CHAPTER XIV
CYCLODUCTION TEST 99
Made with the Combined Use of the Two Maddox Rods 99
Treatment for Cyclophoria 102
CHAPTER XV
MOVEMENTS OF THE EYEBALLS AND THEIR ANOMALIES 105
Monocular Fixation 105
Binocular Fixation 106
Orthophoria 107
Heterophoria 107
Squint 108
Varieties of Heterophoria and Squint 109
CHAPTER XVI
LAW OF PROJECTION 114
Suppression of Image 115
Monocular Diplopia 115
Table of Diplopia 116
Movement of Each Eye Singly 117
Subsidiary Actions 118
Field of Action of Muscles 120
Direction of the Gaze 120
Primary Position—Field of Fixation 121
Binocular Movements 121
Parallel Movements 122
Lateral Rotators 123
Eye Associates 124
Movements of Convergence 125
Movements of Divergence 125
Vertical Divergence 126
Orthophoria 126
Heterophoria 126
Subdivisions 126
CHAPTER XVII
SYMPTOMS OF HETEROPHORIA 128
Treatment 130
Destrophoria and Laevophoria 132
The demands of the day for maximum efficiency in the refracting world
are largely accountable for the inception, continuous improvement and
ultimate development of the master model Ski-optometer.
The present volume, dealing with the instrument’s distinctive operative
features, has been prepared not only for Ski-optometer users, but also
for those interested in the simplification of refraction and muscular
imbalance.
The author is indebted for invaluable counsel, to
Louis J. Ameno, M.D., New York.
E. LeRoy Ryer, O.D., New York.
Jos. D. Heitger, M.D., Louisville, Ky.
W. B. Needles, N.D., Kansas City, Mo.
INTRODUCTORY
While in a measure the conventional trial-case still serves its
purpose, so much of the refractionist’s time is consumed through the
mechanical process of individually transferring the trial-case spheres
and cylinder lenses, that far too little thought is given to _muscular
imbalance_, notwithstanding its _importance_ in all refraction cases.
Dr. Samuel Theibold, of Johns Hopkins University, in a recent address
before the American Medical Association, stated that the average
refractionist was inclined to devote an excess of time to general
refraction, completely overlooking the important test and correction of
muscular imbalance. If the latter is to be at all considered, general
refraction must be simplified—without impairing its accuracy—a result
that is greatly facilitated through the use of the Ski-optometer.
One must admit that tediously selecting the required trial-case
lens—whether sphere, cylinder or prism—watching the stamped number on
the handle—continual wiping and inserting each individual lens in a
trial-frame is a time-consuming practise. This is readily overcome,
however, through the employment of the Ski-optometer.
In a word, the Ski-optometer is practically an automatic trial-case,
bearing the same relation to the refracting room as the accepted labor
and time-saving devices of the day bear to the commercial world.
The present volume has accordingly been published, not alone in the
interest of those possessing a Ski-optometer, but also for those
interested in attaining _the highest point of efficiency_ in the work
of refraction and muscular imbalance.
[Illustration:
_Ski-optometer Lens Battery (almost actual size) showing how sphere and
cylinder lenses are procured._
_After obtaining FINAL results, your prescription is automatically
registered, ALL READY for you to transcribe._
Fig. 1—The three time-saving moves necessary in the operation of the
Ski-optometer.]
CHAPTER I
SKI-OPTOMETER CONSTRUCTION
A far better understanding of the instrument will be secured if the
refractionist possessing a Ski-optometer will place it before him,
working out each operation and experiment step by step in its proper
routine.
The three moves as outlined in Fig. 1 should first be thoughtfully
studied and the method of obtaining the spheres and cylinders carefully
observed.
[Illustration: Fig. 2—To Obtain Plano.]
1—Set spherical indicator at “000” as illustrated above.
2—Set cylinder indicator to “0”.
3—Set pointer of supplementary disk at “open”.
The instrument should then be set at zero or “plano,” a position
indicated by the appearance of the three “0 0 0” at the spherical
register, in conjunction with one “0” or zero, for the cylinder at its
register, marked “CC Cyl.”
After this move, the supplementary disk’s pointer should be set at
“open” (Fig. 2).
[Illustration: Fig. 3—To obtain sphericals, turn this Single Reel as
shown by dotted finger. This assures an automatic and simultaneous
registration at sphere indicator of focus of lens appearing at sight
opening.]
CONVEX SPHERICAL LENSES
A careful study will show that the Ski-optometer’s spherical lenses
are obtained by merely turning the smaller reel (Fig. 3). The
first _outward_ turn of this reel, toward the temporal side of the
instrument, draws into position in regular order the spherical lenses
+.25, +.50, +.75, and +1.D., as shown in Fig. 3a.
[Illustration: 3-A—Outer spherical reel containing Cx. sphericals from
.025 to 1.00D and a blank.]
[Illustration: 3-B—Inner spherical disk containing Cx. sphericals,
automatically turns within 3-A.]
[Illustration: 3-C—Supplementary spherical disk.]
By means of a concealed tooth gear, an inner disk is automatically
picked up, placing its first lens +1.25D in position (Fig. 3b). This
+1.25D spherical lens remains stationary while the outer disk again
revolves, adding to it the original +.25, +.50, +.75 and +1.D.,
the latter totalling +2.25D. At this point, the instrument again
automatically picks up its inner disk, thereby placing its second lens,
+2.50D, in position.
[Illustration: Fig. 4—With the reappearance of “00” at sphere
indicator, a rapid increase or decrease of +1.25 is accurately and
speedily attained.]
Instead of using intermediate strengths in making an examination, it is
frequently desirable to make such extended changes as 1.25D to 2.50D.
With the Ski-optometer, the refractionist will note that two white
zeros appeared at the spherical register in connection with +1.25, and
again with +2.50. A rapid outward turn of the spherical reel toward the
temporal side to the point of the reappearance of the two zeros will
show +3.75D; or, if increased power is still desired, a rapid turn will
draw +5.D. into position (Fig. 4).
Turning the reel inward toward the nasal side will likewise decrease
its convex power. In brief, each one of these lenses, showing their
foci in conjunction with the two white zeros, are signals indicating
the rapid increase or decrease of one and one-quarter diopter. After
continuing to +6D., the next turn automatically shows zero (or
“plano”), the original starting point, which is again indicated by the
three white zeros.
Through the turn of the single reel—an exclusive Ski-optometer
feature—all convex spherical lenses have now been attained in quarters
up to +6.D, practically covering ninety percent of all refraction cases.
[Illustration: Fig. 5—With supplementary disk pointer set at +6 Sph.,
this places an additional +6.D spherical lens at sight opening,
extending instrument’s total convex spherical power to +12.D.]
Should still greater power be desired, the small pointer at the outer
edge of the instrument should be set at +6 sphere (Fig. 5). This
controls a supplementary disk (Fig. 3c) which places an additional
+6D. lens before the original range of lenses previously referred to,
thus increasing the maximum power to +12D. If still greater strength
is required, any additional trial-case lens may be added, a cell being
provided for that purpose on the forward plate of the instrument.
OPERATES AND INDICATES AUTOMATICALLY
As previously explained, in using the Ski-optometer, it is only
necessary to remember that each outward turn of the single reel toward
the temporal side of the patient _increases_ the plus power, while the
reverse turn toward the patient’s nose _decreases_ it. In fact, no
attention need ever be given the register until the required sum-total
is secured, it only being necessary to turn the single reel in order to
be assured of the unvarying and accurate operation of the instrument.
For convenience, the contour or upper edge of the plate covering the
spherical reel has been made to fit the index finger (Fig. 3). Hence
the operator should note that it requires but one complete turn from
extreme side to side, rather than a number of short turns, in order
to bring each individual lens into position, thus obtaining the full
advantage of the automatic spring-stop. This likewise permits the
refractionist to operate the Ski-optometer even though the room is in
total darkness.
CONCAVE SPHERICAL LENSES
Another simple and exclusive Ski-optometer advantage worthy of note is
the method employed in obtaining concave, spherical lenses. Instead of
employing a battery of concave lenses similar to the convex battery
previously described, the instrument’s operation is greatly simplified
through the use of a neutralizing process.
In short, the Ski-optometer only contains two concave lenses to obtain
its entire series—namely, a -6.D and a -12.D sphere (Fig. 3c)—first
setting the pointer of the supplementary disk at -6. sphere, then
setting the indicator of the spherical battery at +6.
Thus zero (or plano) is obtained, the plus neutralizing the minus.
By merely turning the plus or convex spherical reel inward, or toward
the patient’s nose, the convex power is then decreased, naturally
increasing the concave value or total minus lens power. For example,
if the spherical indicator shows +5.D, when the -6D. lens is placed
behind it, the lens value at the sight opening will be -1D (Fig. 6). If
required, the refractionist may continue on this plan until only the
-6D. lens remains.
[Illustration: Fig. 6—With this indicator of supplementary disk, set at
-6.D. Sph. and spherical indicator at +5.D—lens value at sight opening
is -1.D. Sph. This simple arrangement makes it possible to operate the
Ski-optometer with but Single Reel for both plus and minus sphericals.]
Should concave power stronger than -6D. be desired, by placing the
pointer of the supplementary disk at -12D. Sph. and proceeding to
neutralize as before, all the concave powers up to -12D. in quarters
are similarly obtained. For the convenience of the operator, all minus
or concave spherical powers are indicated in _red_; while plus, or
convex powers, are indicated in _white_.
The instrument is also provided with an opaque or blank disk which is
brought into position before the sight opening by setting the pointer
of the supplementary disk at “shut” (Fig. 3c.)
Summing up, all plus and minus spherical powers have been attained from
zero to 12D. in quarters, practically through the turn of the single
reel—_a simplicity of operation largely responsible for Ski-optometer
supremacy_.