Introduction

Summary of the Modern Status of Hering's Law

1. Equal innervation is an important part of Hering's Law. The best modern reading of this is in terms of constraints on neurological control.

2. The law depends on simplicity. There exists a fixed pattern of innervation control, not altered either easily or to any considerable degree by learning, and not changed for different operating condi­tions such as initial position of the eye before a movement.

3. The law is im innate law and depends upon mechanisms incorpor­ated into the 'hardwired' aspects of the brain through evolutionary selection.

4. The motor law has its counterpart in sensory function. The hori­zontal, vertical, and vergence degrees of freedom are important primarily for the sensory system and secondarily for the motor system.

The Single Eye

1. The same innervation ratio occurs in horizontal and vertical muscles for parallel movements independent of the initial position.

2. The vertical muscles act as one unit. The vertical recti and the oblique muscles summate so that the locus plane of the axes of vertical rotations is Listing's plane.

3. The horizontal and vertical planes of action are perpendicular to the line of sight and therefore have no first order effect on cycloro­tation.

4. It is important to distinguish false torsion from true cyclorotation, and to distinguish the values of CH from true cyclorotation. Helmholtz created a table of those values of CH' for various hori­zontal and vertical directions of gaze, for which CL = 0; that is, for which there is no true cyclorotation.

5. The simplicity of the law of constraint and the parallelism of movements with the same innervation ratios from different initial positions depends on two structural mechanical factors. These are the broad insertions of the tendons, and the fact that having four vertical muscles greatly widens the range of the vertical rotation forces.

6. As a consequence, Listing's Law is true within the smaller fixation space.

7. As a further consequence of the simplicity of the law of innerva-

204

Summary 205

tion, Donder's Law is true both within the smaller fixation space and at more extreme positions.

The Double Eye

1. Equal innervation goes to corresponding muscles. 2. The vertical muscles are treated as a single group and thus the cor­

respondence between the two eyes is automatic for versional­vertical rotations.

3. Disjunctive correspondence must be accepted within the frame­work of application of the law to horizontal-vergence movements.

4. Hering mistakenly thought that vertical vergences were not natural, only made small deviations, and should be considered violations of Hering's Law. However, they are natural in that they compensate for disruptions for binocular co-linearity following vestibular­ocular compensation for head tilt. They can be large. Hering's Law can be analogously extended, as for horizontal-vergence, to include them.

5. If we proceed from the initial elegant consideration of Hering's Law for (i) horizontal versional movements to include (li) vertical versional movements by treating the vertical muscles as a single motor, then add (iii) horizontal vergence by defming disjunctive correspondences, then append (iv) vertical vergences in an analo­gous fashion, and finally include (v) cyclorotational versions and (vi) cyclorotational vergences, we arrive at a point where Hering's Law appears to be tautological. Then, Hering's Law may be stated in tB-rms of corresponding movements of the two eyes. Innervation is then that appropriate to the 'equal' eye movements. Indeed, both Hering, in 1879, and the texts of Duke-Elder and of Davson state Hering's Law in this tautological form.

Dynamics

Hering and Helmholtz scarcely made any dynamical observations. We now know dynamic violations of Hering's Law to be common. Indeed, these open the way for a better understanding of the 'hyperfme structure' of eye movements.

References

1. Berthold, Archiv filr Ophthalmologie, Vol. 11/13, p. 107. 2. Burkhard, Poggendorff's Annalen der Physik, Vol. 112, 1861,

p.596. 3. Donders,Holland. Beitrage zu d. Anal. u. Physiol. Wissenschaften,

Vol. 1, 1846. 4. Donders, Ibid., p. 379. 5. Donders, Die Anomalien der Refraction und Accommodation,

1866. 6. Donders,lbid., p. 484. 7. Fick, Zeitschrift f Ration. Medicin, Vol. 4, p. 801. 8. Helmholtz, H., Verhandlungen des Heidelberger medicinisch

naturhistorischen Vereines. May 8, 1863. 9. Helmholtz, H., Archiv filr Ophthalmologie, Vol. 9/2, p. 153.

10. Helmholtz, H.,lbid., p. 189. 11. Helmholtz, H., Physiologische Optik, 1867, p. 471. 12. Helmholtz, H., Ibid., p. 472. 13. Helmholtz, H., Ibid., p. 473. 14. Helmholtz, H., Ibid., p. 474. 15. Helmholtz, H., Ibid., p. 519. 16. Helmholtz, H., Ibid., p. 522. 17. Hering, E., Beitrage zur Physiologie, Vol. 3, 1863. 18. Hering, E., Beitriige zur Physiologie, Vol. 3, 1863, and Vol. 4,

1864. 19. Hering, E., Archiv f Anat. u. Physiol. 1865, p. 164. 20. Listing, Lehrbuch der Ophthalmologie von Reute, p. 14. 21. MacGillavry, Onderzoekingen over de Hoegrootheid der Accom-

modatie, 1858. 22. Meissner,Archiv filr Ophthalmologie, Vol. 2, pp. 1-123. 23. Meissner, Beitrage zur Physiologie des Sehorganes. 24. Muller, J., Handbuch der Physiologie, Vol. 2, 1840. p. 103. 25. von Recklinghausen,Archiv filr Ophthalmologie, Vol. 5/2, p. 143. 26. Reute, Ein Neues Ophthalmotrop, p. 8. 27. Volkmann, Neue Beitriige zur Physiologie des Gesichtsinnes,

1836, p. 148. 28. Weber, E.H., Programmata collecta. Summa doctrinae de motu

iridis, 182. 29. Wundt, W., Archiv filr Ophthalmologie, Vol. 8/2, p. 1.

206

References for Introduction and Commentaries

Alpern, M. Movements of the Eyes. In Davson, H. (Ed.), The Eye, 3-187. New York: Academic Press, 1962.

Blakemore, C. Environmental Constraints on Development in the Visual System. In R. Hinde & J. Stevenson-Hinde (Eds.), Constraints on Learning, 51-74. London: Academic Press, 1973.

Bahill, A.T., Ciuffreda, K.J., Kenyon, R.V., & Stark, L. Dynamic and static violations of Hering's law of equal innervation. Am. J. Op t. , in press, 1976.

Bahill, A.T. & Stark, L. Neurological control of horizontal and vertical components of oblique saccadic eye movements. Mathe­matical Biosciences 27, 287-298, 1975.

Bahill, A.T. & Stark, L. Dynamic and static violations of Hering's Law of equal innervation. American Journal of Optometry and Physiological Optics 53, 798-808, 1976.

Boring, E. A History of Experimental Psychology. New York: Appleton-Century-Crofts, 1950.

Brecher, G. Die optokinetische AuslOsung von Augenrollung und rotatorischem Nystagmus. Arch. ges. Physiol. 234, 13-28, 1934.

Coleman, W. Biology in the Nineteenth Century: Problems of Form, Function, and Transformation. New Yark: Wiley & Sons, 1971.

Cranefield, P. The organic physics of 1847 and the biophysics of today.J.HistoryofMed.12, 407-423, 1957.

Davson, H. The Physiology of the Eye (3rd edition). New York: Academic Press, 1972.

De Valois, R. & Jones, A. Single cell analysis of the organization of the primate color-vision system. In R. Jung & H. Kornhuber (Eds.), The Visual System: Neurophysiology and Psychophys­ics. Berlin: Springer-Verlag, 1961.

Duke-Elder, S. & Wybar, K. System of Ophthalmology. Volume 6: Ocular Motility and Strabismus. London: Henry Kimpton, 1973.

Elias, H. The liver cord concept after 100 years. Science 110, 470-472, 1949.

Garten, S. Ewald Hering zum Gedlichtnis. Arch. ges. Physiol. 170, 501-522, 1918.

Helmholtz, H. Physiologische Optik. Leipzig: Voss, 1867. Helmholtz, H. Physiological Optics. Transl. by Southall, J.P.C., 1925:

Reissued by Dover Press, New York, 1962. Hering, E. Beitrllge zur Physi%gie. Leipzig: W. Engelmann, 1861-

1864. Hering, E. Die Lehre vom Binokularen Sehen. Leipzig: W. Engel­

mann, 1868(a).

207

208 References for Introduction and Commentaries

Hering, E. Die Selbststeuerung der Atmung durch den Nervus vagus. Nach Versuchen von Breuer. Sitzber. d. k. k. Akad d. Wiss. zu Wien 57, 672, l868(b).

Hering, E. Uber das Gedlichtnis als eine allgemeine Funktion der organisierten Materie. Vienna: C. Gerold's Sohn, 1870.

Hering, E. Zur Lehre vom Lichtsinn. Vienna: C. Gerold's Sohn, 1878. Hering, E. Der Raumsinn und die Bewegungen des Auges. in L.

Hermann (Ed.), Handbuch der Physiologie, 3(1). Leipzig: F. Vogel, 1879. Transl. as Spatial Sense and Movements of the Eye, by C. Radde. Baltimore: Am. Acad. Optom., 1942.

Hering, E. ErkHirung der Farbenblindheit aus der Theorie der Gegen­farben. Lotos 1, 13, 1880.

Hering, E. Uber die spezifischen Energien des Nervensystems. Lotos 5, 116, 1884.

Hering, E. Grundzuge der Lehre vom Lichtsinn. Berlin: Springer, 1920. Transl. as Outlines of a Theory of the Ligh t Sense by L. Hurvich & D. Jameson. Cambridge: Harvard U. Press, 1964.

Hering, E. & Sherrington, C. Uber Hemmung der Kontraction willkiirlicher Muskeln bei elektrische Reizung der Grosshirn­rinde. Arch. ges. Physiol. 68, 222-228, 1897.

Hoffman, F. & Bielschowsky, A. Uber die der Willkiir entzogenen Fusionsbewegungen der Augen. Arch. ges. Physiol. 80, 1-40, 1900.

Hurvich, L. Hering and the scientific establishment. Am. Psychologist 24,497-514,1969.

Kertesz, A. The effect of stimulus complexity on human cyclofusion­al response. Vision Res. 12, 699-704, 1972.

Kertesz, A. & Jones, R. Human cyclofusional response. Vision Res. 10, 891-896, 1970.

Ogle, K. Researches in Binocular Vision. New York: Hafner, 1964. Pribram, K. & Bridgeman, B. Retinally-oriented vs. environmentally­

oriented modification of early visual environment. In prep. Stark, L. Neurological Control Systems: Studies in Bioengineering.

New York: Plenum Press, 1968. Svaetichin, G. Spectral response curves from single cones. Acta

Physiol. Scand. 39, Supp. 134, 17-46, 1956. Ullman, E. About Hering and Breuer. In R. Porter (Ed.), Breathing:

Hering-Breuer Centenary Symposium. London: J. & A. Church­ill, 1970.

Verhoeff, F. Cycloduction. Tr. Am. Ophth. Soc. 32, 208-228, 1934. Wundt, W. Uber die Bewegung der Augen. Arch. f Ophth. 8, 1-78,

1862.

Index

abductor group, 66 abductors, 50, 188 absolute far point, 196,202 absolute strength of

innervation, 47 ACA ratio, 201,202 accommodation, 16, 21, 28-30,

50,59,133,150, 183-185, 187-195,200-203 monocular, 45 muscles, innervation of, 187 negative, 45

accommodative convergence, 159,201

accommodative innervation, 183 achromatic action, 190 active pulling forces, 27 adductors,50, 179, 187, 188, 193 afterimage, 28, 62, 83, 91, 92,

94-100, 104, 105, 107, 108 112, 113, 132, 136148-150, 161 intensive, 132 method, 103, 113, 116

Alpern, 9 alternate binocular fixation, 190 angle of inclination, 85, 86 angle of rotation, 161 animals, 36, 178 antagonism, deviation from, 171 antagonist, 154, 163, 164, 166,

170,171 antagonistic innervation, 27,54 antagonistic muscle groups, 53 antagonistic muscles, 25, 27, 47,

73,181 apparatus, 106, 107, 109, 110,

127 apparent direction, 142 apparent movement, 190 apparent rotation, 90 apparent rotation of

afterimage, 98, 104

associations of movement, 187 associations of voluntary

movements, 22 asthenopia, 188,201 astigmatic action, 189, 190 asymmetrical convergence, 5, 22,29,200,201,203 attention, 28, 42, 68 attention, selective, 68 automatic control, 47 automatic focusing, 34 awareness of eye movements, 41 axes of eye movements, 6

ofrotation,146,167 of rotational force, 154, 157

axioms of biology, 2 axis plane, quadrant of, 170

Bahill, T, 146,181 ball, 81, 82 Balliet, 146 baseline, 137 Beale, 7 Becker, 88, 90 Bell, Charles, 180 Berthold, 115, 121, 126,149 bifixation, 14, 17,182 bifixation point, 200 bifixation space, 83 binocular accommodation

depth, 193 accommodation range, 195, 198 disparity, 150 far point, 196,202 fixation, 5, 66, 67 fixation field, 65 fixation line, 19 fixation space, 66, 67 images, 116, 149 lines of sight, 25 motors, 7 near point, 202 poin t of vision, 42

209

210

vision, 201 visual field, 52

bite board, 28, 105, 107, 108, 148

"black box", 72 blinded,23 blind spot, 103 blur, 188, 201, 202 blur circles, 30,45,183, 200 Boring, 11 brass tube, 91 Breuer, 12 broad insertions, 153, 180, 181 Briicke, 2, 10 Burkhard, 36

cancellation, 69, 201 cardboard strip, 93, 94 cardinal movements, 147, 149 Cartesian space, 7 Carus, 3 cells, 2 chemistry, 3 child, 175, 177, 194, 195 choice of muscles, 166 circular rotation, 14, 92, 101, 129 color vision, 10 common action, 37 common action of muscles, 50 compensatory rolling, 88 competition of innervations, 24 compulison, 23, 33

for accommodation, 196 to equal innervation, 36

compulsive linking, 23, 68 concave glasses, 192, 197, 199,

203 cone, 74, 75 cone of rays, 62 congenital refraction errors, 196 conic surface, 79, 80, 102, 103 conjugate, 37,73 conjugate movements, 39

Index

consensual contraction, 188, 200 conservation of energy, 2 con tact lens, 9 continuous rotations, 75 control experiments, 114 con tro1 theory, 1, 12 convergence, 17,21,41,45,59,

116, 128-130, 132, 137, 138,179, 187-196,201, 203 angle, 19, 136, 139 involuntary, 134 positioning, 127 unsymmetrical, 55, 133

converging lines of sight, 149 converging squint, 44 convex glasses, 195, 198, 199,

203 coordinate system, 182 coordination of the eyes, 5 coordinations, 21, 22, 33 corollary discharge, 148 covered eye, 23, 29, 38, 184 cover points, 143, 144 cyclodisparity, 146 cyc1ofusion,5, 7-10,146 cyclopian eye, 68 cyclorotation, 8-10, 14,16,

27,87, 120, 128, 133, 142, 143,146-148,150,151,164, 171,175,178,180-182 apparent, 31 involuntary, 146 voluntary, 143

cyclorotary orientation, 55, 83, 84,127, 141

cyclorotary position, 14, 175, 182

cyclovergence, 146, 149 Czermak, 183

Darwin,152 Dastich, 137

The Theory of Binocular Vision

degrees of freedom, 181 depth dimension, 53, 89 depth perception 144 Descartes, 22,71-73,180,181 De Valois, 11 deviation angles, 137 deviation of one eye, 32, 37,

59, 190, 191 deviation, vertical, 51 diagnosis, 199 diplopia, 198,201,202 direction of eye movements, 43,

48 of muscle pull, 161 of the double eye, 57 of vision, 53

discontinuous rotations, 75 disjunctive cyclorotation, 8-10 displacement of image, 56 distance, absolute, 43 distance accommodation, 28 distance vision, 66, 92 distortion of afterimage, 97 disturbance of motility, 35 divergence, 9, 66, 117, 124, 189 divergence angle of vertical

dividing lines, 120, 121 diverging squint, 65 Dodge, 70 dominance, 68, 191, 192 Donden,~ 32,63,84,85, 103,

138,186, 187, 192, 194, 195,200-202

Donders' Law, 7, 72, 133,146, 159,181

double contour, 9, 88 doubled muscles, 70, 173 double eye, 1,7,14,17,25,27,

29,39,48,55, 7~ 14~ 183,201 innervation of, 46

double images, 23, 32, 34, 44, 56,60,61,67,90, 105, 111,

127, 184, 189 unequal,44 vertically displaced, 32

double retina, 144 double vision, 88, 198,203 Dove prism, 89, 146 du Bois-Reymond, 2 dynamics, 7, 70, 146

ears, 85 education of muscle

movements, 22 efferent copy, 148 elastic forces, 153 elastic threads, 153, 154 electrophysiology, 10 Elias, 7

211

emmetropic, 197,203 empiricist, 2,4-6,73,150,151 entoptic experiment, 200 equatorial section, 77 equal innervation, 17, 23 equal innervation, law of, 22 equilibrium position, 156 error ranges, 113, 114 estropia,201 evolution, 151,152 exactness of eye movement, 48 excursion ability, 198 exotropia, 202 experimental approach, 73 experimental prowess, 11 experimental techniques, 147 experiments, 2, 4,12,35,68,

73,83,90,94,105,114, 185 eyeball, 74, 153, 155 eyeglasses, 192, 199 eye movement control, 7 eye movements, 4 eye muscle names, 15 eye muscles, 7, 83, 153

false innervation, 58

212

false torsion, 147, 148 far object, 45

positions, 129 vision, 28

fatigue, 28 Fechner, 3 Fick, 103,147.151, 156 fields of sight, 88 fish, 69, 182 fixated object, 42, 58 fixation, 92, 94, 95, 100, 104,

107,108,142,183 aligner, 105 line, 19 line of double eye, 21 plane, 25, 53,111,120, 121, 127-31,134,135,137,144, 193 point, 19,46,53,89, 132, 177 position, 55, 85 space, 67, 70, 83

of double eye, 62 larger, see "larger fixation

space" smaller, see "smaller fixation

space" fixed axis, 92 fixing of head, 105, 185 focus, 25, 183, 188 forces of rotation, 146 foreshortening, 108, 122 frame of reference computation,

70,151 Freud,12 functional associations, 178 Funke, 3 fused image, 87, 88 fused vision, 86, 121 fusion, 8, 9, 30,32, 86, 90, 126,

146, 189, 197

gait, natural, 37

gaze, 95 gears, 72 Geometric inferences from

Listing's law, 10 1-1 03 geometrical projection, 144 Gestalt, 156 Gestalt Psychology, 11 glass pane, 28, 62

Index

goal point of movement, 42, 48 graded potentials, 10 Greeks, 1, 2

habit, 187, 194 half axes, 74, 76-82, 154-158,

169-171, 175, 178,180 of rotational force, 75 of true rotation, 157

hand posture, 49 harmony between sensory and

motor functions, 21,56 head,91,92,185

holder, 105, 108, 120 movement, 47, 53 po~tion,35,45,62, 107

heartbeat, 84 Helmholtz, 1-6,10,11,14,15,

22,34-36,55, 59, 70, 73, 84,85,87-90,92, 101, 103-105, 108, 111-116, 121,124, 125, 129, 137, 143, 146-152,154,175,180, 182, 187, 196,200, 202

Hering, H.E., 12 Hering's Law, 1, 5,6,146,203

corollary of, 7 dynamic violations of, 70, 146

Hillebrand, 12 horizontal axis, 77

fixation plane, 137 muscles, 181

horopter, principle of largest, 144,151

horsehairs, 120

The Theory of Binocular Vision

Hurvich, 7, 12 hyperbolic path, 161 hyper-fine structure, 70, 71 hypennetropia, 188, 194, 197,

198,201-203

identical meridians, 86, 87 imaginary eye, 19,21 imagining of object, 42, 44 impulse for movement, 49 impulse of will, 17, 19,50 inborn,S, 73, 194

associations, 37, 179, 196,201, 202 capability, 37, 38 coordinations,S, 22,36,38, 51 mechanism, 141,150,152, 178 organization, 11,39,55,56, 176,177,195

independence of movements, 22 indirect vision, 85 individual differences, 135 infmite1y small rotations, 82,

146, 157,158 inheritance, 6, 141,152 inhibit, 19 innate, 68, 203 innervation, 17, 46, 51, 83-85,

167,178,183,187,188,191, 192, 198 of abductors, 197 of adductors, 187, 197 antagonistic, 27, 54 cessation of, 156 corresponding, 39, 52 equal, 23-25, 29, 33,57, 185,200 fixed pattern of, 182 for focusing, 188 involuntary, 186 law of, 54, 56,60, 153, 166,

174,177,179,180,182 of raisers, 172 relationships, 54 sim ultaneous, 21

213

unequal, 198,203 voluntary, 21, 30, 200 independent of fixation, 58

insertion lines, 153 insertions, broad, 153,180,181

of eye muscles, 54, 158, 159 of obliques, 60

intellectual ability, 6 interocular distance, 126 interocular muscles, 50, 183, 200 intersecting images, 88 introspection, 12 in-turners, 50 inversion of field of sight, 89 involuntary deviation, 59 iris, 7, 50, 185 iris refelx, 185

Japanese inn, 147 J osephsakademie, 4 judgement of position, 58

Kant, 6 kinematics, 3,4,146,147,

180,182 Von Kries, 6

language, 57 larger fixation space, 47, 113,

143 lateral movement, 24 lateral rectus, 60, 170, 198,202 law of equal innervation, 22, 50,

56,60 laws of muscle actions, 50, 59,

61 learning, 150,180,182, 196 left hand, 39 left-hand rule, 74

214

left-turners, 50 Leipzig, 3, 4, 11 Lemansky, 70 lens, convex, 186 light level, 185 line of sight, 14, 25,62, 74,

78,80,81,83,89,90,92,94, 101-103, 105, 107, 113, 116, 117,123-126, 131,149, 153, 155,161,171,172,175,176, 196

line segments, 142 lines of sight, 16, 25, 27, 28, 32,

61 listing, 3, 92, 103, 134,147,

182, 186, 200 Listing's Law, 7, 72, 92,93, 101,

104,107,108,111,116,117, 120,121,129,131,132,135, 137,141,143, 144,147,150, 151,157,165,167,168,171, 173-178,181,182 corollary, 94 deviations from, 108, 117, 129,133,134,144,149, 171 geometric inferences, 101-103

.Listing's plane, 147 liver, 7 localization of image, 29 10werers, 50, 171 Ludwig, 2

MacGillavry, 192, 195,202 Mach,3 magnitudes of resistance, 164 main sequence, 71 Mandell, R. 42 mathematical inexactness, 27,

54,61 mechanical aspects of eye

movements, 180 mechanical considerations, 55,

182

Index

mechanical relationships, 175 mechanisms, 2, 4 medial rectus, 170, 187, 193,

194, 198 median plane, 27, 28, 52, 173 Meissner, 103, 127, 134, 135,

151 memory, 12

of innervation feeling, 45 meridian plane, 101 meridianal deviation, 101 method of investigation, 117 microscopy, 2 middle longitudinal sections, 116 mirror, 110, 113,149 mirror image muscle systems, 57 misalignment, threshold of, 32 momentary or instantaneous

axes, 74, 92, 171 moments of rotation, 76-80,

82,156-158,166-168,171 monocular fixations fields, 64,

65 motility disturbances, 197,199 motives, 141 motor functions of double eye,

54 motor independence, 33 motor system, 39

of body, 178 motors of vision, 51 mouche volante, 42, 56, 68 movement, common, 23

involuntary, 41,185 reciprocal, 39 symmetrical, 36, 37, 39,57, 58 unequal, 22, 29 unsymmetrical, 37, 39, 57 voluntary, 151, 185

Muller, Joh, 2,4,5, 21,22, 187, 200

muscle, 133, 153, 154

The Theory of Binocular Vision

action, 49 combination, 168, 176 elasticity, 197 force, static, 69 groups, 50-52, 54, 59, 83, 173 habits, 36 mechanisms, 59 plane, 154, system, 177, 178

myopia, 188, 193, 194, 196-198, 201-203

Nagel,22 Nakayama, 146 nativist, 2, 6, 73,150,151 nature-nurture controversy, 6 Naturphi1osophie, 2 near accommodation, 28 near object, 44 near position, 129, 131, 179 near vision, 27, 28, 59, 66 needle, 81,110,122 neurological control theory, 1 neurological linking, 73 newborn,S, 36,37,73,141,

178,179,182 Newton, 10 nodal points, 62 non-corresponding retinal

locations, 32 nose contour, 63 nystagmus,S, 23

object indirectly seen, 43 object of attention, 42 oblique movement, 52, 53,

70, 71, 95, 177 obliques, 155, 163-165, 172,

175,176,178,182 oculomotor control theory, 68 Ogle, 9 open-loop, 150

215

opthaimologists, 166, 195, 197, 202

opponent processes, 10 optic nerve, 176 optical advantage, 179 optical apparatus, 87 orbit, 100, 153 orbital insertions, 154, 159 organizations of sensory

apparatus, 6 onentation, 14, 16,92,131,177

laws, 150 of double eye, 134 of retinas, 58, 98

oscillation, 192, 201 outflow theory, 4 out-turners, 50

pair of eye muscles, 167 Panum's fusional area, 8 parallel lines, 8, 86 parallel lines of sight, 123, 144 parallel position, 44, 117, 120,

123, 124 parallelogram, 76, 80-82 paral1e1opiped, 76, 153 paralysis, 23, 60 paresis,S, 60,61,180, 197, 198,

202,203 paretic muscle, 71, 182 path of line of sight, 161 pathology, 164, 194, 187-199 patient, 197,203 perception, 3,4, 41, 142

of depth, 144 spatial, 41, 45

peripheral field of vision, 52, 54 penn anent axis, 74 Pfluger, 7 phenomonology,ll philosophy, 2, 3, 6 photographic method, 9 physics, 3

216

physiological optics, 3, 6, 7, 14, 148

physiologists, 166 physiology, 2, 3, 10, 12 plane of the axes, 102

of primary axes, 94, 168, 171 of muscle action, 180

plumb lines, 122 point of rotation, 74

of sight, 19,43,83,87,95, 187 of vision, 28

Porterfield, 22 pointers, 118 practice, 22, 39, 42,48 practiced observer, 37 Prague, 10 primary axes, 94, 102 primary axis, common, 155 primary colors, 10 primary deviations, 71 primary fixation plane, 135 primary half-axis, 154-156, 163 primary meridian planes, 94, 103 primary point, 98 primary position, 64, 92-95, 99,

101, 102, 107, 113, 120, 129, 134, 135,147-149, 155,156 161,162, 166-168, 170-173, 175,177,178,181 change in, 178

primary vertical meridian plane, 95, 101

primary visual plane, 131 prism, 5, 32,34,88-91, 183,

189-191,197,201 prognosis, 199 projection relationships, 98 psychology, 3, 11, 12, pulling forces, 170 pupiL 45, 185, 186, 190,200 Purkinje, 10 purposeful direction of eyes, 44

pursuit eye movements, 7 pyramids, 75

quadrilateral, 82

Radde, 14

Index

Raddrehung, 14, 92, 101, 129 raisers, 50, 51,169-173 range of line of sight, 62-64 ray of light, 91 reciprocal innervation, 71, 72,

181 Recklinghausen, 125, 135, 137 rectus muscles, 175, 176, 197,

198 reflex movement, 34, 56, 57,

200 refraction anomalies, 195

condition, 199 state, 29, 183

regulation of eye muscles, 54 reinforce, 19 reins, 1, 68 relative accommodation

distance, 187 relative accommodation range,

192, 193 relative direction of object, 44,

48 release of innervation, 53 resistances, 157, 158, 161-164,

167,171,176,180 respiration, 12 resting position, 157 resultant moment, 78, 172 retinal image, 29, 59, 88, 97,

142, 144, 189 meridian, 83, 142 position, 166,148,149

determination, 104 Reute, 103, 154, 159 right-angled cross, 95-97, 148 right-turners, 50

The Theory of Binocular Vision

rolling of eye about line of sight, 8,14,83-87,92-95,100, 101, 104, 105, 117, 132, 133, 135 141,163-165,172,173,176

rotation about vertical axis, 162 rotational force, 15,75,76,80,

153,156,161,162, 164, 166, 167, 171

rotation of afterimage, 98, 100 of head, 143 point of eye, 77, 81,106,110, 118,128, 153, 159

rule of orientation, 103

saccadic eye movements, 7, 152 Schleiden, 2 Schopenhauer, 22 Shuunnann, 137 Schwann,2 scientific rivalry, 4 secondary deviations, 71

location, 102 po~tion,94, 103, 166, 171-173

second-order effects, 182 sectors, 155, 156 security of movement, 158 sensory physiology, 1 Sherrington, 12, 180 short sightedness, 122 sideward turners, 187, 192 simple rotations, 81 simplicity of innervation, 141 single eye, 153

eye muscle, 158, 171, 180, 197,202 motor, 181 muscle mechanisms, 153 muscle operation, 56

single-valued function, 46 single vision, 191 six motors of vision, 51 sleep, 34, 68

217

slide indicators, 125, 126 smaller fixation space, 7, 47,

70, 101,111,113, 114, 143, 146

sneezing, 50 sole contraction, 164 Southall, 15 spatfal conceptions, 42, 48, 54,

85 perception, 151 relationships, 141

special innervation, 175 sphere, 78 squint, 23, 35,44,65,90,183,

188,194,195,197,201 static muscle force, 69 stationary axis, 74 steady fixation, 85, 86 stereoscope, 8, 56,88, 146,

201 stereoscopic double image, 192

experiments, 32, 85, 87,123 picture, 84

strabismus, 195 straignt line movements, 80 string, 92 successive rotations, 80 Svaetechin, 10 synergy, 187 systems approach, 71

teeth, 105, 107, 117 tendons, 153 ~n~on,26, 153, 156, 162, 166 tension, common, 169, 170 threads, 93, 153, 154 tilt, 130, 131 tilt of fixation plane, 136, 139 tilt of head, 94, 117, 120 tongue, 85 trial and error, 107 tube, 123 twitching, 27

218

unpracticed,42 useless for seeing, 23

vergence, 68, 69, 146, 149, 182, 201

vernier, 118 version, 68, 69, 200 vertical axis, 77

combinations, fixed, 181 dividing lines, 14, 116,120, 129,131,132,134,137, 178 lines, 88 meridians, 120, 173 mid-sections, 14 musculature, 72, 181 plane, 99, 100 projection, 159 retinal meridian, 95, 101 vergence, 69

vestibular action, 149 Vienna, 4, 10 virtuoso, visual, 6, 177 visual plane, 19, 137,149 visual pointer, 112, 113, 115 visual space, 4, 49, 51, 189, 197 vitalism, 2, 4

Index

Volkmann, 116, 125, 126, 137, 187,200

voluntary accommodation change, 197 eye movements, 141 innervation, 21, 30,200 movements, 151, 185

association of, 22 pupil size reduction, 45 rolling, 85, 87, 90

Weber, E. R., 3,45,187,188, 200

Wheatstone, 22 will, 1, 84, 178, 183

goal of, 41 window, 28, 62

wooden frame, 104 writing, 39, 49 Wundt, 3,4,8,22, 103,151,

172

yoked pair of oxen, 68 Young, 10

Zeitgeist, 3 zone of single, clear binocular

vision, 201