History of Ophthalmology: Sub auspiciis Academiae Ophthalmologicae Internationalis

150 Pages·1990·1.68 MB·English

by  Charles H. Barnes (auth.)

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ehT polar etanidrooc system and Listing’s Law
The ylno coordinate metsys rof gnibircsed eye rotations that seod not evah
eseht swalf si the polar coordinate .metsys In a polar coordinate metsys the
position of the eye si osla determined yb owt :selgna enO elgna senifed the
direction of eye movement out of the primary position and a dnoces elgna
senifed the elgna of eye movement out of the primary position. In siht
coordinate ,metsys lla tertiary positions of ezag are reached yb elpmis
rotation about a elgnis .sixa sihT elpicnirp saw detnevni yb Professor .B.J
,gnitsiL a good dneirf of Professor ,eteuR ohw had participated with Ruete
ni eht Gottinger Studien htiw a booklet on entoptic phenomena and cataract
.)5481(
Ruete )3581( therefore dellac siht elpicnirp Listing’s :waL ’Aus der oben
nenebegegna normalen gnulletS ,gnulletssgnafnA( Primarstellung) sed
seguA driw sad eguA ni dnegri enie andere, ,eradnuces durch eid Coopera›
tion der shces Muskeln ni der esieW ,tztesrev ssad man hcis eseid gnuztesreV
sla das Resultat einer Drehung ennriue etmmitseb Drehungsaxe nelletsrov
kann, ehclew jederzeit, durch das Augencentrum ,dneheg auf der primaren
und secundaren Richtung der optischen exA hcielguz senkrecht steht, os
ssad osla jede secundare gnulletS sed seguA zur primaren ni der Relation
steht, egomrev rehclew eid auf eid ehcsitpo exA projicirte Drehung = 0 .driw
meseiD Princip eglofuz tssal hcis aus der bekannten egaL red ierd auf je iewz
antagonistische Muskeln nehcilgiizeb Drehungsaxen rUf jede enebegeg
Secundarstellung sed seguA der Wirkungsbetrag sedej ,sleksuM .i.d eid
Grosse renies gnuzriikreV durch Rechnung .nemmitseb Unter ned
nehcafleiv Consequenzen seseid spicnirP tneidrev eid hervorgehoben uz
,nedrew ssad hcilman das eguA mieb Uebergange aus renie secundaren
gnulletS ni enie andere enie ihrer Grosse nach bestimmbare Drehung nru
enies optische exA erfahrt, ehclew nur ni med besonderen Fall llun ,tsi nnew
eid ierd Richtungen der optischen exA ni der primaren und ni den nedieb
secundaren gnulletS ni renie enebE ’negeil ni( short, lla secondary and
tertiary positions of ezag can eb reached yb rotation about a elgnis sixa that
si perpendicular to the primary position of ezag and to the wen position of
ezag . . . Among the many secneuqesnoc of siht ,elpicnirp eno sdeen par›
ticular ,sisahpme ,yleman that the eye lliw rotate about sti optical sixa ni eye
stnemevom from eno tertiary to another tertiary position of ,ezag siht
rotation gnieb orez ylno nehw the owt tertiary positions of ezag and eht
primary position of ezag are lla ni a elgnis ).enalp
ehT Ophthalmic Collection of the former Royal Netherlands Ophthalmic
Hospital has a copper ledom that illustrates siht elpicnirp yllufituaeb .giF(
.)1 The name of the ecalp of manufacture, ,ellaH si engraved ni the .ledom
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.giF .J Ophthalmotrope morf the Ophthalmologic Collection of eht former Royal Nether›
lands Ophthalmic Hospital ni Utrecht, probably tnes yb Ruete ot Donders (– ,)2581
demonstrating Donders’ and Listing’s :swaL lla secondary and tertiary positions of ezag can
eb reached yb rotation about a elgnis sixa that si perpendicular to eht primary position of ezag
and ot eht wen position of ezag . The primary position of ezag si at the tfel ni the .erugif The
eye si represented yb a small globe ni eht center of eht .ledom Two sleehw with spokes
(representing eht horizontal and vertical retina meridians) are mounted on the tips of an sixa
representing the position of .ezag This position-of-gaze sixa can tilt about the oblique sixa
representing an sixa in Listing’s .enalp At the front of the model tfel( ni eht picture) an arc
representing a horizontal meridian ni space can eb tilted upward : one can ees that eht
horizontal retina meridian si tilted relative to eht meridian arc (Donders’ pseudotorsion). At
the back of eht model, a vertical are , representing a vertical meridian ni ,ecaps can eb turned
together htiw the second spoked :leehw Donders’ pseudo torsion si found to occur ni eht
opposite direction. The horizontal and lacitrev arc meridians correspond to eht yaw straight
horizontal and vertical senil ni space are deviecrep yb the eye ni eht center of eht :ledom In
the experiments of Donders, eh compared horizontal and vertical retina meridians htiw
horizontal and vertical senil on a llaw ni front of ,mih eseht are represented ni siht model yb
the meridian arcs .
Halle si about 03 km from ,gizpieL os it saw probably Ruete who sent this
model to Donders.
In Ruete’s tsrif ophthalmotrope )5481( the model eye saw suspended in
gimbals, .e.i the model eye rotated ni a ring that itself could rotate about an
sixa that saw perpendicular to the tsrif ,sixa this method of suspension
having neeb invented yb Cardano in the sixteenth century. An improved
version of sih ophthalmotrope, presented yb him in gizpieL ni ,7581 no
longer employed suspension with gimbals. The globe saw simply pulled
against a ring with swercs by the ’muscles’. It can now eb nees yhw Ruete
did not employ a gimbal suspension in the second version of sih ophthal›
motrope: siht kind of globe suspension lliw not bring the eye in a tertiary
position that complies with Listing’s :waL Pseudotorsion lliw occur in
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Fig . .2 Ruete’s dnoces ophthalmotrope. Note that the seye are not suspended ni gimbals ekil
ni Ruete’s tsrif ophthalmotrope , esuaceb then Listing’s waL dluow eb .detaloiv
tertiary positions of .ezag Ruete wrote that the ring with swercs supporting
the model eye represented the ’fat pad behind the ,eye the nutshell in which
the eye saw suspended’, quite a modern concept for sih .emit Donders )0781(
later presented sih own ophthalmotrope to illustrate Donders’ .waL nI this
model eh desu gimbal suspension on purpose, to make the pseudotorsion
available . This ophthalmotrope saw equipped with a camera obscura, to
obtain an image ,fo for instance, the left upper hand corner of the llaw in
front of .su This image saw to eb compared with the retinal meridians, which
erew represented by 4 copper bars surrounding the camera obscura.
ehT nosaer for Listing’s Law
What si the reason of the ecnetsixe of Listing’s Law or, in other words, yhw
si there a primary position, from which lla other eye positions can eb reached
yb elpmis rotation about a elgnis sixa or, in other words, yhw isn’t the
primary position in left upper gaze rof instance?
Von Helmholtz compared Listing’s Law with the minimal energy con›
dition in physics .)3681( Applying this principle in a broader ,esnes one
could yas that Listing’s wal si probably the consequence of the fact that the
primary position si the average of lla eye positions during the day, that most
eye movements are directed radially from or to the primary position and
that rotations about a elgnis sixa are easier to perform than rotation about
001
a
.giF a3 and b. Models to demon s trate and to quantify Donders’ pseudotorsion, from eht
museum of eht former Royal Netherlands Ophthalmic Hospital ni Utrecht. In eseht models
Donders su ed gimbal ssu nep s ion on purpose , to make eht ps eudotorsion iv s elbi labmig(
suspension results ni ebolg rotations that do not conform to Listing’s )waL . The lanif version
(Fig . )b3 saw debircsed yb Donders ni 0781 . The ophthalmotropes erew equipped with a
camera obscura, to obtain an egami of , rof instance , the tfel upper hand corner of eht llaw ni
front of su ; siht egami saw to eb compared htiw the retinal meridians w, hcih erew represented
yb 4 copper bars surrounding eht camera obscura 2( are broken off) . The eye rotated ni eht
two sexa or about an sixa that changes during the movement. eyE ›evom
ments from tertiary positions to other tertiary positions do occur, but are
ssel frequent and do not occur predominantly in down- , -pu , right- or
.ezag-tfel During eye movement from one tertiary to another tertiary
position , Listing’s wal si dellifluf only if the rotation takes place about an
sixa that si tilted to Listing’s plane yb half the elgna neewteb the momentary
tertiary position and primary position (von Helmholtz :)3681 ecneh an sixa
that can change during the movement.
The primary position (Ruete ,)3581 sa determined with afterimages
(Hering, ,8681 p. 74-83) seirav over emit (von Helmholtz ;0191 Schubert
1927), si ni down - ezag for convergence (Donders 6781 ees )woleb and seirav
with head position (Fisher )2291 .
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b
inner ,gnir and eht inner gnir rotated ni the outer gnir of eht gimbal suspension, eht primary
and secondary sexa of rotation gnieb perpendicular. The outer gnir si ni Listing’s frontoparal›
iel plane’ and ti could rotate ni sti ekil-eveels circular holder, os that the primary sixa of
rotation could tilt nihtiw Listing’s ,enalp ,ecneH a tertiary position of ezag could ,eb incorrect›
,yl reached yb rotation about eht primary horizontal and secondary lacitrev sexa (resulting ni
pseudo torsion) or yb tilting the primary sixa of rotation ni Listing’s plane and subsequent
rotation about eht primary sixa only ni( compliance htiw Listing’s .)waL
Ocular counterrolling
Donders initially assumed that lla rotation of the seye about the optic ,sixa
saw pseudotorsion. The ecnetsixe of true rotation about the optic ,sixa
’ocular counterrolling’, saw deined yb .mih Ocular counterrolling si a llams
counterrolling movement of both seye about the lausiv sixa nehw the head
si tilted towards either shoulder, caused yb the otolith .xelfer True ocular
counterrolling had already neeb described in 6871 yb John Hunter, but had
subsequently neeb overestimated yb Hueck ,)8381( who thought that it ylluf
compensated for up ot 52.82 seerged of head-tilt to either shoulder. Actu›
,ylla Hueck had only ,nees not measured, the torsional nystagmus nehw
tilting the head of another person from shoulder to shoulder. Then eh
measured, in an anatomical study, the distance that the superior oblique
tendon could eb pulled out of the trochlea, hcihw saw ."5.5 He erroneously
assumed that the superior oblique elcsum had torsional action, ,ylevisulcxe
and nevig eht diameter of the eye eh estimated the maximum amplitude of
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torsional eye movement to eb 5.65 .seerged (In more recent measurements,
the actual amplitude of ocular counterrolling saw found to eb 46.5 – .d.s
75.2 ged on 05 ged head-tilt either yaw in 55 normal seye yb Nelson and
Cope ,)1791( ew found 35.5 – .d.s 59.1 ged on 54 ged head-tilt either yaw
in 23 normal seye zsnomiS( .)4891
Ruete and Volkmann initially deveileb Hueck nov( Graefe ,)4581 but later
deined the ecnetsixe of true ocular counterrolling when pseudotorsion saw
tsrif described by Donders, and the edUtilpma of ocular counterrolling
claimed yb Hueck saw not found. ,ecneH Donders’ denial of the ecnetsixe
of true ocular counterrolling saw supported yb von Graefe )4581( and von
Helmholtz ,)3681( but lla had to revoke later (Donders ,)5781 when ocular
counterrolling saw rediscovered yb Javal in .6681
Ocular counterrolling si accomplished by the concerted action of vertical
rectus and oblique eye .selcsum The superior rectus and superior oblique
selcsum of one ,eye and the inferior rectus and inferior oblique selcsum of
the other eye contract, saerehw their antagonists .xaler This laitnereffid esu
of eye ,selcsum depending on head-tilt to either shoulder, has important
consequences for patients with a yslap of the trochlear evren that innervates
the superior oblique eye .elcsum
A patient with a trochlear evren yslap lliw prefer a head tilt that confers
ocular counterrolling such that the paretic elcsum si not .dedeen Under eseht
circumstances the elgna of squint si llams and double noisiv si absent. On
head tilt towards the contralateral shoulder the elgna of squint steg yrev
.egral This principle has neeb formulated yb Nagel ,)1781( tsrif applied
yllacinilc yb Baumeister ,)4781( and elaborated yb Hoffmann and
ykswohcsleiB .)0091( (Baumeister saw a ressel known pupil of Donders; in
the emas article, ,revewoh eh osla described the dependence oflatent nystag›
mus upon the direction of ezag for eht tsrif )!emit
Excyclotropia no convergence
A third kind of torsion that has confused investigators si excyclotropia on
.ecnegrevnoc Excyclotropia lacitrev( retina meridians tilting esiwkcolc in the
right eye and anti-clockwise in the tfel eye sa nees from the patient’s )edis
on ecnegrevnoc saw found yb Hering ,)8681( Donders ,)6781( Landolt
,)6781( Allen )4591( and others. eW osla found it to occur during voluntary
ecnegrevnoc gnisu a double-looped larelcs search lioc zsnomiS( and ,eeZ
unpublished .)stluser Why should excyclotropia occur during ?ecnegrevnoc
The most ylekil reason saw formulated yb Donders :)6781( Convergence
occurs during near noisiv and near noisiv si done mostly in .ezag-nwod If the
primary position rof near noisiv si ni down-gaze (for the emas reason sa yhw
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I
Fig . .4 Wundt’s ophthalmotrope )2681( . elcsuM secrof erew represented by sthgiew and
.sgnirps
the primary position rof far ezag si approximately ahead, sa dessucsid
above) excyclotropia lliw occur nehw converging from ezag ahead. One can
calculate and extrapolate the primary position for near noisiv from the
excyclotropia that occurs during ecnegrevnoc from ezag ahead .
ylnO nehw converging the seye yb more than 01 ,ged corresponding to a
target distance of ssel than 53 ,me ssecxe excyclotropia has been found to
occur, not accounted for yb assuming a lower primary position rof down›
,ezag but more than 01 seerged of ecnegrevnoc si of course a yrev unnatural
condition .
s’tdnuW eportomlahthpo
The most sophisticated model of eht nineteenth century ,saw no doubt, that
made yb Wundt in Heidelberg, ’ein sehciltsniik Augenmuskelsystem zur
Untersuchung der eztesegsgnugeweB sed menschlichen seguA mi gesunden
und kranken Zustande’ .)2681(
Whereas Ruete’s ledom used anatomical variables only , Wundt’s model
osla desu lacigoloisyhp variables sa elcsum ,secrof represented yb springs
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and weights. Remarkable in his analysis si that the spring constants of his
model muscles were directly related to the cross-sectional area of the muscle
and inversely related to the length of the muscle, as determined in post›
mortem studies. As a matter of fact, Donders (1848) had already measured
the weights of the muscles to determine their relative force. (He found for
human eye muscles that were dried at 001 deg C after removal of the tendon:
0.072, 0.0725, 0.0603, 0.075, 0.032 and 0.0265 g for lateral, medial, superior
and inferior rectus muscles, and superior and inferior oblique muscles,
respectively.) In his article, Wundt )2681( presented the changes of muscle
length, force and other parameters in 20/20 deg secondary and tertiary
positions of gaze.
Coordinate systems for gnibircsed eye movements
In the coordinate system used most commonly in the diagnosis and treat›
ment of squint, first the horizontal angle of a particular gaze position si
described, and then the vertical angle (Fig. 5a-b, middle-left). This coor›
dinate system was first employed by Fick .)4581( It si an isoazimuth and
isolatitude system, similar to the coordinate system used to designate a place
on earth and similar to the system used in the Major Amblyoscope and
Synoptometer. Its great disadvantage si that, in tertiary positions of gaze, an
angle designated, for instance, ’30 degrees’ si larger vertically than horizont›
.ylla (For comparison: on earth the distance between one of the latitude
circles and the equator si the same everywhere, whereas the distance between
the vertical meridians decreases towards the poles).
Imagine that the coordinate system used to describe eye positions si drawn
onto a globe. The observer si in the center of the globe. Imagine that the
observer si looking from the center of the globe onto some point on the
equator of the globe, and designate this point the primary position. Al›
though the angles of the intersections of the latitude circles and the vertical
meridians are all perceived by the observer as rectangular, the directions of
the latitude circles and the vertical meridians ,lliw nevertheless, not coincide
with the horizontal and vertical meridians of the retina of the observer, they
lliw both be tilted (Donders’ law, .)6481 If this coordinate system (Fig. ,aS
middle left) were projected onto a screen in front of the observer, it would
consist of vertical lines (projections of meridians) and horizontal hyperbolas
(projections of latitude circles) (Fig. 5b, middle left).
The problems described above would be solved by using a polar coor›
dinate system (Fig. 5a-b, middle right). Here, one angle defines the direction
of eye movement and a second angle defines the amount of eye movement
out of the primary position, following Listing’s Law (Ruete ,)3581 that ’all
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secondary and tertiary positions of ezag can eb reached yb rotation about
a elgnis sixa that si perpendicular both to the primary-position ezag ›cerid
tion and to the wen ezag direction. ,revewoH the trigonometric calculations
teg yrev xelpmoc nehw one sesu siht metsys and selgna of squint would have
to eb desserpxe in a totally tnereffid .yaw
Von Helmholtz ,3681( )0191 osla desu a isolatitude-isoazimuth coor›
dinate ,metsys but desu isolatitude horizontally and isoazimuth yllacitrev
.giF( ,5 top ,)tfel the esrever of Fick’s .metsys nA( equivalent of siht coor›
dinate metsys on earth would eb to have the northpole in Columbia and the
southpole in Indonesia.) He argued that the trigoniometric calculations erew
relpmis gnisu siht ,metsys nehw stfihs in the ecnerefer point, the primary
position, occurred: The primary position (Ruete ,)3581 sa determined with
afterimages (Hering, ,8681 .p 74-83) seirav over time (von Helmholtz ;0191
Schubert ,)7291 si in ezag-nwod rof ecnegrevnoc (Donders )6781 and seirav
with head position (Fisher .)2291
The selgna neewteb eht horizontal meridians and lacitrev latitude selcric
in the metsys of von Helmholtz are also deviecrep sa rectangular yb the
observer at the center of eht ebolg but, again, the directions of the horizontal
and lacitrev senil do not ,edicnioc ni tertiary positions of ,ezag with the
horizontal or lacitrev meridian of eht retina of the :revresbo They are won
both tilted the other .yaw
nI a coordinate metsys that si isoazimuth both syaw (meridians both
horizontally and yllacitrev on the ebolg or, projected onto a ,neercs straight
horizontal and lacitrev ,)senil the selgna neewteb the horizontal and lacitrev
senil are deviecrep yb the observer sa larger than 09 ged .giF( ,b-a5 bottom
.)tfel An example of eht esu of siht coordinate metsys si the ’Tangen›
tenskala’, a frontoparallel neercs htiw straight horizontal and lacitrev senil
on ,ti introduced yb Harms .)1491(
sseH )6191( introduced a coordinate metsys with isolatitude horizontally
and yllacitrev .giF( ,b-a5 top right) that emaceb yrev popular sa eht ’Hess
.’neercs It si often desu for measurements of the elgna of squint ni sesac of
eye elcsum .yslap ,revewoH the selgna neewteb eht horizontal and lacitrev
senil of eht sseH neercs are deviecrep yb eht observer sa smaller than 09 .ged
gnilloK and zsnomiS )6891( assumed that neewteb the two latter coordinate
smetsys there should eb another erehw lla selgna would eb deviecrep yb the
observer sa rectangular.
They then re-invented a metsys based on ’direction ’selcric .giF( ,b-a5
bottom .)thgir The ’direction ’selcric represent the direction of the horizon›
tal and lacitrev meridians of eht retina in tertiary positions of ezag (von
Helmholtz .)0191 When an observer sevom sih ,seye from emos tertiary
position, constantly in the direction of the retinal horizontal or lacitrev
meridian, the sixa of rotation si neither in Listing’s plane (isolatitude), nor
6Ol
--- (cid:0)~(cid:0)-(cid:0)-(cid:0)-(cid:0)-
-tI
(/l
/
\
"
’-
Fig.5a.
si the sixa of rotation perpendicular to the direction of ezag (isoazimuth).
The sixa of rotation si between these two .giF( .)6 Such an sixa si the only
possible elgnis sixa that the eye can rotate about, going from one tertiary
position to another tertiary position and complying with Listing’s .waL
Now a curious mathematical peculiarity of direction selcric si that lla
direction selcric go through the ’occipital point’ (von Helmholtz .)Ol91 The
occipital point si a point behind the observer. The occipital point si exactly
in the direction opposite to the primary position.
Now, for construction of the coordinate system, consider only those
direction selcric that have either a common horizontal or a common vertical
tangent in the occipital point. A seires of vertical selcric and a seires of
horizontal selcric result .giF( .)7 The direction selcric lliw represent the
direction of the horizontal and vertical meridians of the retina in tertiary