Ernest Edmund Maddox.

Tests and studies of the ocular muscles online

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Ophthalmic Surgeon to Royal Victoria Hospital, Bournemouth ; formerly Syme
Surgical Fellow, Edinburgh University


Specially revised and enlarged by the author






That a second edition of this book should be asked for affords
pleasant compensation for the time and thought it cost.

In the choice of terminology, I have carefully refrained from
the dislodgment of ancient landmarks. Thus the words "adduction"
and "abduction" will be found retained in their time-honored
sense a sense which is stamped on the very name of " abducens"
muscle itself, and the dislocation of which would make the classics
of Graefe and Bonders, Helmholtz and Mauthner less intelligible.

The announcement, by one author and another, of supposed
errors in the treatment of Listing's law by Bonders and by Helm-
holtz have compelled me, even in these uncontroversial pages, to
enter more fully into the laws of the parallel motions of the eyes
than their clinical importance would perhaps otherwise warrant.
The purely clinical reader can, if he prefer, pass over the section
which shows these discoveries to be groundless.

My thanks are due to Br. Asher, of Leipsig, tor several
suggestions from the German edition, one of which has led me to
add a chapter on Nystagmus.

E. E. M.




The Ball of the Eye Ocular Muscles Normal Motions Orbits-
Tenon's Fascia Check Ligaments Their Functions Internal Cap-
sule Tenon's Space Bearing of Check Ligaments on Tenotomy.


Translations of the Globe Listing's Plane False Torsion
Bonder's Law Listing's Law Helmholtz's Plane of Reference
Donder's Plane of Reference Index of Torsion Use of False
Torsion Azimuth and Altitude.


Law of Innervation Description of the Recli Spiral of Insertions
Description of Obliques Subsidiary Functions Medial Origin
of Muscles Superductors and Subductors Lines of Force
Muscular Planes Axes of Rotation Paralytic Equilibrium Con-
secutive Deviation Arc of Contact Ophthalmotropes Landolt's
Ball Tilted Axes.


Isolated Contraction of some Muscles Unknown Superducting
Muscles for Example Motion from Secondary Positions Compo-
sition of Rotations Dynamics Moments Resolution of Rotations
Co-ordination Vertical Purchase of Recti and Obliques altered
by Adduction and Abduction Purchase of same Muscles about
Vertical Axis Paralytic Exophthalmos Model with Tilted Axes
Paralytic Semi-orbits.


S Tests and Studies of the Ocular Muscles



True Associates Spasm of Single Muscles Conjugate Innerva-
tions Conjugate Paralyses Convergence Confirmation of Rules
of Conjugation Convergence and Accommodation Effort and
Work Exophoria in Oblique Vision Latent Deviations.


Point of Fixation Direct and Indirect Vision Fixation-reflex
Persistent Fixation Binocular Fixation Projection Correspond-
ing Points Physiological Diplopia Suppression of Images
Origin of Projection Fusion Power of Overcoming Prisms
Breadth of Fusion Power Monocular Perception of Distance
Stereoscopic Vision of Relief Hering's Drop Test.


Definition Chief Division Strabismus Convergens Accommo-
dative Non-accommodative Predisposing Causes Congenital
Amblyopia Nervous Element of Strabismus Imperfect Central
Fixation Strabismus Incongruus Recovery of Lost Faculties
Extension of Partially Preserved Faculties Strabismus Convergens
Myopicus Alternating Squint Unilateral Squint Operations
Strabismus Divergens Refractive After-treatment for Squints
Javal's Course of Treatment Natural Cure of Squint Evidences
of Squint Secondary Deviation Fallacy from Anisometropia
Apparent Squint Intrinsic Aberrations of Eyeball Linear Stra-
bismometry Hirschberg's Method Perimeter Method Charpen-
tier's Method The Tangent Strabismometer Subjective Strabis-
mometry Paralytic Strabismus.


Symptoms Order of Examination Diplopia Aphorisms, Incor-
rect and Correct Complications Diagnostic Procedure Narrow-
ing Circles Dextral and Laeval Torsional Purchase and Vertical
Purchase Brief Summary Confirmation of the Diagnosis
Measured Charts To Read a Simple Chart To Read a Multiple
Chart Independent Diplopise Clinical Classification of Muscles.

OCULAR PARALYSES {Continued) 165

Optical Illusion How to transfer Charts to Opposite Eyes Paraly-
sis of Right External Rectus Paralysis of Left External Rectus

Contents 9

Qualifications in Paralysis of the External Recti Paralysis of Right
Internal Rectus Paralysis of Left Internal Rectus Qualifications
in Paralysis of the Internal Recti Paralysis of Right Superior
Rectus Paralysis of Left Superior Rectus Paralysis of Right
Inferior Rectus Paralysis of Left Inferior Rectus Paralysis of
Right Superior Oblique Paralysis of Left Superior Oblique
Paralysis of Right Inferior Oblique Paralysis of Left Inferior
Oblique Paralysis of the Third Nerve Test for Fourth Nerve
Measurement of Ocular Paralyses Conjugate Paralyses Tests for
them Tropometer Precise Tests for Convergence Mnemonics
for Ocular Paralyses Dangers of Mnemonics Werner's Mnemonic.


Definition Rapidity Apparent Motion Examination of Etiology
Nature of the Excursions Treatment of Nystagmus Curiosities.


Precautions Fixation Position of the Corneal Reflection Apparent
Squint Refraction Surmisable The Reflection in Cataract and
Iridectomy Tests for Monocular Blindness Alternation Conco-
mitancy Test for Binocular Fixation Hirschberg's Rule for
Squint Priestley Smith's Mode of Strabismometry Different
Points of View Error of Approximation Photography of Muscu-
lar Anomalies Author's Camera Recording Reflections.


Chief Divisions Dissociation of the Eyes Physiological Hetero-
phoria Direction of Deviation Hyperphoria Objective and Sub-
jective Tests Prism Tests Glass Rod Test and its Allies Two
Species of Cylinder Manufacture Mode of Use Measurement of
Latent Deviations Rare Anomaly Previous Tangent Scales
Advantages of the Tangent Scale Which Eye Fixes ? Other Uses
of the Scale Test for Concomitancy Trial Test for Reliability
Heterophoria in Near Vision Mode of Use Its Meaning Physio-
logical Exophoria Prism Diopters in Near-Vision Tests Inter-
mediate Scales Tests for Breadth of Fusion Correction of Hyper-
phoria Relative Importance of Correction Concomitancy vs.
Paresis Horizontal Breadth of Fusion Orthoptic Training
Simple Rules for Heterophoria Rules for Decentering : Prism
Diopters Direction of Decentering Example Prism Diopters
Operative Interference Graduated Tenotomy Marginal Tenotomy.

io Tests and Studies of the Ocular Muscles



Its Detection and Clinical Measurement Its Exact Measurement
Paretic Cyclophoria Non-paretic Cyclophoria Explanation of
Leaning Image Rule for Rod Test Cyclophoria in Near Vision
Oblique Astigmatism Cyclophorometers Optomyometer Clino-
scope Volkmann's Apparatus Meissner's Test Depression of
the Visual Plane True Primary Position in Distant and in Near
Vision Le Conte's Confirmation Savage's Test Compared
Eaton's Apparatus Formula for Meissner's Test.


The Visual Camera Deviation in Near Vision Sense of Projec-
tion Effect of Attention on the Desire for Fusion Speed of the
Exophoria Laws of Conjugation Illustrated False Fusion
Diluted Fusion.


1-2 Axes, Poles and Equator 17

3-4 Tenon's Fascia 19, 21

5-7 Check Ligaments 22, 23

8 Horizontal Section of the Globe and its Membranes .... 24

9-10 Diagrams showing effect of Tenotomy 26, 27

ii Check Ligaments 29

12 Vertical longitudinal section of Eyeball and its adnexa . . 30

13 View of under-surface of the Eyeball 31

14 Author's Torsion Calculator .... 43

15 Author's Design for solving False Torsion 47

16 Diagram showing how the Eye reaches a new position by the

shortest route 48

17-21 Diagrams illustrating Torsion 49, 50

22 Muscular Planes and Axes 59

23 Landolt's Ophthalmotrope 63

24 Anderson Stuart's Model of Ocular Muscles 64

25 Landolt's Ball 65

26 Tilting of the Axes 66

27 Helmholtz's Diagram for motion from one secondary posi-
tion to another 69

28 Composition of Rotations 71

29 Composition of Muscular Forces 72

30 Planes of Corneal Orbits 73

31 Model with Tilted Axes . 76

32 Diagram illustrating Conjugation 87

33-36 Diagrams illustrating Convergence and Accommodation . . 88, 92

37-38 Figures for the Field of Fixation 101

39 Diagram illustrating Mis-projection 106

40 Proximal and Distal Diplopiae in

41-43 Stereoscopes HI, 112, 113

44 Home-made form of Hering's Drop Test 114

45 Ophthalmoscopic Corneal Reflections in Normal Eyes . . . 137

46-47 Diagrams illustrating Perimetric Methods of Measuring

Squint 140

48 Diagram to illustrate "Spherical Aberration " 141

49-5 1 First and Second Steps in Tangent Strabismometry . . 142, 143, 144

52 Landolt's Dynamometer 154

53 Schweigger's Hand Perimeter 155

54 Dextral and Laeval Muscles 162

55 Mnemonic Attitude for Muscular Planes 162


1 2 Tests and Studies of the Ocular Muscles

56 Method for Inscribing Charts 165

57-70 Charts of Ocular Paralyses . . 169, 170, 172, 173, 174, 175, 176, 177

178, 179, 181, 182

71 Tangent Scales 183

72 Specimen of Chart Entry 183

73 Kick's Motor Chart 186

74 Stevens' Tropometer 190

78 Corneal Reflections in Normal Eyes 199

79 Diagram showing Obliquity of Visual Axis with reference

to Geometrical Axis 200

80-81 Diagrams showing Symmetry and Asymmetry of Normal

Eyes 203

82 Unsymmetrical Angles Gamma 204

83 Priestley Smith's Tape Method 206

84 The Caustic Curve of a Convex Mirror 207

85 Analysis of Corneal Reflection 208

86 Photograph of Ascending Convergent Squint 209

87 Author's Camera for photographing Reflections 209

88 Photograph of over-correction, immediately after advance-
ment 211

89 Chart of Congenital Defect of Right Superior Rectus . . 211

90-91 Author's Double Prism 217

92 Prisms of Stevens' Phorometer 218

93 First form of the Glass-rod Test 220

94 Diagram showing Use of Rod Test 221

95 Dioptric Tape Measure 222

96 Author's Tangent Scales 223

97-98 Trial-Frame for Use of Prisms 228, 229

99 Diagram showing Prismatic Effect of Decentering ... 232

100 Savage's Test . . 238

100% Illustrating Oblique Astigmatism 239

101 Optomyometer of the Geneva Optical Company .... 241

102 Stevens' Clinoscope 242

103-105 Haploscopic Figures 243, 244

106 Eaton's Apparatus for Meissner's Test 246

107-108 Author's Plan for solving Meissner-Torsion 248

109 The Visual Camera 251

no Camera for Testing Projection 254






The Globe and Its Socket

The motions of the eyes are notable for their combination of
silence, swiftness and precision.

The silence of the eye, or, at least, the absence of audible
sound, is all the more remarkable because of the proximity of the
organ of hearing and the ready conduction of sound by bone.

The swiftness of the eyeball itself is not, perhaps, greater
than that of adept fingers, nor is it desirable that it should
be in the interest of its delicate contents; yet the act of winking
or "twinkling of the eye" has always been accepted by com-
mon consent as the briefest measure of time expressible by the
human body.

The precision of the ocular movements, together with the
perfect co-ordination of the two eyes, is the most important virtue
of the three, and is evidenced in thousands of ways every day.
One example only need be given, namely, that in watching a small
moving object in the distance, such as a bird a mile away, it is seen
single instead of double, which could not be unless both eyes
followed the object with the keenest exactness.

Akin to this we may mention the steadiness of the eyeball in
observing a fixed point ; a steadiness, however, which is not
inherent in the ocular muscles, but which is maintained by an
exquisite "visual reflex" mechanism.

When the eyelids are closed the globes are in almost perpetual
motion, as any reader may verify by laying the tips of his fore-
fingers over the closed upper lids: moreover, if one eye be covered
while the other is observing with comparative steadiness a fixed
point, the covered eye does not share the steadiness of its fellow,
but wavers slowly from side to side. This is easily demonstrated
by the author's "visual camera" (Chapter XIV), which detects
the movements of an eye placed in the dark.


1 6 Tests and Studies of the Ocular Muscles

Even in the light, an eye is unsteady unless occupied with a
fixed object, as when, for instance, it only sees a false image of an
object, the true image of which is seen by the other eye.

The absolute steadiness of the eye during the study of minute
objects, is entirely beyond our voluntary control, and I think we
may fairly describe the parts played by volition and reflex action
respectively, when we say that the former directs the eye, and the
latter steadies it. It is true that in daily life the point of fixation is
constantly on the move, but then it does not move in a wavering
way, but purposefully, and in looking at an object it flits, as it were,
from one salient point to another, dwelling upon each long enough
to let the mind grasp the new picture presented each time.
Lamare's ingenious plan of making the movements of the eye
audible by a kind of binaural stethoscope attached by a point to
the upper lid, showed that four or five slight movements take place
during the reading of one line, and a greater movement when we
begin to read a new line.

Under ordinary conditions we can turn our eyes at pleasure
from one object to another, but there is a peculiar pathological
state in which this faculty fails, and in which this visual reflex
appears to gain the upper hand, so that the eyes can with difficulty
be made to look away from the object last looked at. To this
subject we shall recur later on.

The Ball Of the Eye- When we consider the spheroidal shape of
the eyeball, and the character of its motions, we need not wonder that
astronomical language has been so freely drawn upon for their descrip-
tion. Thus we speak of the globe moving in its orbit (metaphorically
like a planet), and distinguish its axis, poles, meridians and equator.

The anterior pole is the mid-point of the cornea in front: the
posterior pole the mid-point of the sclerotic behind (as in Fig. i).

The axis of the eye, often called the "optic axis," extends
between these poles. '

The equator is a circle or belt of the globe midway between
the two poles.* (Fig- 2.) >

The meridians are circles, each of which passes through both
poles so as to have the axis of the eye for their common diameter.

In the study of the ocular motions we assume the eyeball to be

* This definition of the equator is an anatomical one. Physiologically, its axis coin-
cides with the visual line, if we think of vision ; or with the fixation line if'we are occupied
with the nrular motions. Since the eyeball is not a geometrically true body, it is customary
t" disregard the little discrepancies between the position of the anatomical equator aud those
of the visual and fixation lines.

The Globe and Its Socket

Fig. I

spherical, though it is not strictly so, but flattened Irom before
backwards, more like an "oblate spheroid," interrupted by
the prominence of the cornea in front, which has a stronger

Ocular Muscles. Each
eyeball receives the inser-
tions of six muscles, namely,
four recti and two obliques.
The recti have an almost
common origin around the
optic foramen (embracing
the optic nerve at its en-
trance into the orbit) and
course forwards, diverging as they go to embrace the globe
for a short distance before reaching their insertions.

The superior and inferior oblique muscles act upon the eye
from the upper and lower corners respectively of the inner v/all of
the orbital outlet.

The motions of the globe take place unerringly under the
guidance of these six delicately-proportioned muscles, the
importance of whose contribution to our daily comfort is not
realized till one of them is disabled from any cause, and we
see double.

Normal Motions. The eye is so suspended in position that its
ordinary movements are limited to those of rotation, no appreciable
translation being possible. It is true that
certain animals possess a "retractor muscle
of the globe," capable of drawing the eye
deeper into the recess of the orbit, but in
man, exophthalmos and enophthalmos are
only known as pathological conditions, due,
in part, to such causes as variations in the
size of the palpebral aperture, varying pres-
sure ot the lids, varying tone of the extra-
ocular muscles ; turgescence or spasm of the
retro-ocular blood vessels, spasm and relaxation of the unstriped
"orbital muscle'' of Muller, which spans the spheno-maxillary
fissure ; and possibly also to contraction or relaxation of the
unstriped muscular fibres described by Sappey as existing in the
internal and external check ligaments near their orbital insertion.


iS Tests and Studies of the Ocular Muscles

It is probable that there occur, even in health, slight unnoticed
physiological variations in the prominence of the eyes.

Orbits. The orbits are two deep conical excavations in the
skull, the anatomy of which is too well known to need description.

At the apex of the cone are two apertures, the optic foramen
and the sphenoidal fissure, the former transmitting the optic nerve
and the ophthalmic artery, the latter all the other nerves but one,
and the ophthalmic veins. The inner walls of the two orbits are
almost parallel to each other, but the outer walls slope outwards
so strongly that the axes of the two orbits (represented by imaginary
lines from the apices to the centers of the orbital outlets) diverge
from each other by from 24 to 30. The conical shape of the
orbit is to accommodate the cone of muscles, and its apparently
superabundant capacity is to permit the globe to be sufficiently
packed in with orbital fat which plays a very important part in the
formation of its socket.

The orbital outlet is narrowed a little by the incurving of its
upper and outer margins, and its outer margin is considerably
posterior to its inner. From a series of measurements which. I have
made, the outer margin of the bony orbit appears to be, on an
average, about 22 mm. behind the root of the nose, 12 mm. behind
the anterior ridge* of the lachrymal groove, and even 7 mm. behind
the depression for the trochlea of the superior oblique. A needle
run transversely inwards athwart the outer margin of the orbit
would, it is said, pierce the center of an average eyeball. But
great differences exist. The orbit is i^ inches deep, while its
outlet is i)^ inches broad and i^ inches high.

It is evident that the large size and conical shape of the orbit
would make it by itself a most unsuitable socket for the eye to
work in ; but, as a matter of fact, the eyeball comes nowhere in
contact with it, and it may be regarded rather as a strong scaffolding
for the real socket, as well as a storehouse for the orbital contents.
The real socket is the capsule of Tenon, in conjunction with its
supporting bed of orbital fat, supplemented by the concave surface
of the eyelids in front.

Tenon's Fascia. All the structures contained within the orbit
are invested by sheaths derived from one and the same aponeurosis.
The cornea, which, at first sight, appears to be an exception to this

* The ridge referred to is the front edge of the groove formed by the superiol
maxilla and lachrymal bone.

The Globe and Its Socket 19

rule, is not, of course, strictly within the orbit. This "orbital
fascia " is in some places or parts of it exquisitely differentiated to
suit the requirements of the ocular motions, and where it surrounds
the sclerotic forms the outer layer of Tenon's capsule, or, in other
words, the external capsule of the eye. It is lined by a delicate
internal capsule, which is of a different nature, being regarded by
some as the serous membrane (/. e. , the pericardium or pleura) of
the eyeball.

The common aponeurosis of the orbit extends from one struc-
ture to another, splitting to encapsule each, but it is convenient to
commence its study by distinguishing that part of it which is
specially in relation to the ocular muscles.

We have already seen that the orbit contains a group of
muscles which spring from the circumference of the optic foramen,
and separate as they proceed forwards, so as to form a cone.

Ensheathing this muscular cone there is a fascial cone, which
extends from muscle to muscle, splitting to invest each with a
fibrous sheath, and sending off layers here and there to enclose
lobules of fat, vessels and nerves.
This cone of fascia is attached at the
apex of the orbit to the periosteum
round the optic foramen, and widens
as it advances till it gains the orbital
outlet, to be rigidly attached to the
periosteum all round the margin.

There is, therefore (as shown at
Fig- 3 ), a kind of cone of fascia

Fig. 3

within a cone of bone, with this dif-
ference between them, that while the bony cone contracts at its
brim, the fascial cone expands at its brim, so that an interval exists
between the two which is filled up with the peri-ocular fat, the extra-
muscular fat, the lachrymal gland, etc. Fig. 3 shows very clearly
how the eyeball is suspended in this cone, from above, and from all
sides as well as from below ; so that the part beneath the eyeball,
which partly supports it as on a hammock, receives too much credit
by the name hitherto given to it, of "the suspensory ligament of
the eyeball."

The fascial cone lodges the eyeball in front, and the retro-bulbar
fat behind. It is divided into two compartments an anterior one
for the eyeball, and a posterior one for the retro-bulbar fat by a

2o Tests and Studies of the Ocular Muscles

hemispherical aponeurotic septum {P. E. C. in Fig. 4), which
adapts itself to the posterior hemisphere of the eyeball. This
septum is given off from the fascial cone just opposite the equator
of the globe all around, and from the same line of origin springs a
companion membrane (A. E. C. ) which passes forward over the
anterior hemisphere, investing it pretty closely as far as the margin
of the cornea, where it becomes attached.

These t\vo eye-investing membranes are regarded as forming
one capsule, known as Tenon's external capsule. It sends pro-
longations backwards in the form of a sheath for the optic nerve
(separated from it by the supra-vaginal lymph space) and for the
various vessels and nerves which enter the eye, and though nothing
more than a part of the common aponeurosis of the orbit, is endowed
with remarkable elasticity.

Since on reaching the edge of each muscle the fascial cone
splits into two layers, one to cover the orbital surface of the muscle
and the other to cover the ocular surface, we find on studying a
longitudinal section of a muscle that we have to take account of
these two layers, as in Fig. 4. The deep layer (D. ) becomes con-
tinuous at the equator of the eye (/ C. L.} with the posterior hemi-
sphere of Tenon's capsule (P. E. C. ), so that from thence forwards the
deep surface of the muscle and its tendon have no fascial investment.

When we consider the orbital layer of each muscle-sheath we
find the case is not so simple. As it approaches the neighborhood
of the globe it thickens, and becomes more closely attached to the
muscle itself, till opposite the equator the attachment reaches its
maximum ; after that it quits the muscle altogether, though not
until it has sent off a prolongation forward over the tendon to
contribute to the anterior portion of the globe's investment
(A. E. C. ), and proceeds in the form of a thick band (Ext. C. L. )
to the orbital margin.

Check Ligaments. The thick band, just spoken of, is not a
separate structure, but only a greatly-thickened strip of the anterior

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Online LibraryErnest Edmund MaddoxTests and studies of the ocular muscles → online text (page 1 of 23)