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Strabismus and Insertion of Horizontal Rectus Muscles
695
EFFERENT FIBERS
VOL. 68, NO. 4
which formed normal radiations. The calcarine cortex was normal. ADDENDUM
Since this manuscript was submitted for publica tion, a significant article has appeared in the lit erature (Haberland, C. and Pérou, M. : Primary bilateral anophthalmia. J. Neuropath. Exp. Neurol. 28:337, 1969). The authors describe a patient in whom no ocular tissue was found in the orbits, and in whom the optic nerves, chiasm and optic tracts were totally absent. The lateral geniculate bodies were dysplastic and atrophie, the optic radiations were absent, the visual cortex was small and the stripe of Gennari was absent.
REFERENCES
1. Honrubia, F. M. and Elliott, J. H. : Efferent innervation of the retina: I. Morphologic study of the human retina. Arch. Ophth. 80:98, 1968. 2. Wolter, J. R. : The centrifugal nerves in the human optic tract, chiasm, optic nerve and retina. Tr. Am. Ophth. Soc. 63 :678, 1965. 3. Mann, I. : Developmental Abnormalities of the Eye. Philadelphia, Lippincott, 1957, ed. 2, p. 66. 4. Wolter, J. R. and Lund, O. E.: Reaction of centrifugal nerves in the human retina : Two weeks after photocoagulation. Am. J. Ophth. 66:221, 1968. 5. Mann, I. : The Development of the Human Eye. New York, Grune and Stratton, 1964, ed. 3, p. 143.
STRABISMUS AND I N S E R T I O N O F H O R I Z O N T A L RECTUS MUSCLES JOSEPH H.
GOLDSTEIN,
M.D.
Brooklyn, New York
The distance from the limbus to the inser tion of the lateral and the medial rectus mus cles is given by most standard textbooks1"3 as 6.9 mm and 5.5 mm, respectively. These measurements, based on a series of enucle ated eyes, were reported by Fuchs 4 in 1884. After reviewing previous publications, Gat5 reported on a series of cadaver eyes in which he measured the distance from the limbus to the insertion of the horizontal rectus mus cles. These measurements represented essen tially normal eyes. In view of the assertion by Scobee6 that 90% of all cases of heterotropia have some underlying anatomic basis, and the fact that the accepted measurements represent essentially normal eyes, the present study was undertaken to determine the varia tion in the limbus-insertion distance of the lateral and of the medial rectus muscles in eyes with strabismus and to evaluate its rela tion, if any, to the clinical findings. From the Division of Ophthalmology, Depart ment of Surgery, Downstate Medical Center, State University of New York. This paper was presented in part at the Annual Alumni Meeting, State Uni versity of New York, Downstate Medical Center. Reprint requests to Joseph H. Goldstein, M.D., Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, New York 11203.
MATERIALS AND METHODS
All measurements were made at the time of surgery in patients operated upon for strabismus. After the muscle was cut from the globe, one arm of the caliper was placed at the midpoint of the base of the insertion of the muscle and the distance was measured to the limbus on a line perpendicular to the in sertion. All measurements were made on the medial or lateral rectus muscles. The limbus was considered the junction of opaque sclera with cornea. Measurements were made to the nearest 0.2 mm. RESULTS
A total of 64 patients were included in this study. Measurements were taken on 72 medial rectus and 73 lateral rectus muscles. The medial rectus muscle insertion ranged from 3.5 mm to 6.0 mm, and that of the lat eral rectus muscle from 4.5 mm to 8.0 mm. These measurements were compared with those of Gat who performed the same mea surements on 80 adult cadaver eyes. The av erage limbus-insertion distance of the medial rectus was 5.07 mm in the present study and 5.40 mm in Gat's study. The average lim bus-insertion distance of the lateral rectus
696
AMERICAN JOURNAL OF OPHTHALMOLOGY
OCTOBER, 1969
TABLE 1 LLMBUS-INSERTION DISTANCE NORMAL VERSUS STRABISMUS Goldstein
Rectus Muscle
No. of Muscles
T
72 73
Medial Lateral
Aver I n
t^
™ (mm)
n
5.07 6.45
TABLE 2 AGE DISTRIBUTION
Age (yr)
No. of Patients
Under 3 3-13 14 and over
6 43 15
TOTAL
64
was 6.44 mm in this study and 6.61 mm in Gat's study. Statistical analysis indicates that for the lateral rectus muscle the difference between the two series (0.17 mm) is not sig nificant but that for the medial rectus this difference (0.33 mm) is highly significant (p < 0.01) (table 1). It might be suggested that an accurate analysis cannot be made because of the difference in age between the subjects in Gat's series and the patients in the present study. The age distribution of the latter is shown in Table 2. Since the eye attains over 95% of its adult size by the age of three,7 and since only eight measurements were in cluded on patients under three years of age, these comparisons were considered accept-
Gat
Muscles
Insertion (mm)
Aver™
Significance of Difference
80 80
5.40 6.61
Yes p < 0 . 0 1 None p > 0 . 0 5
No. of
e
able. The data was reanalyzed, however, ex cluding these eight values; the results were the same. The measurements were analyzed to de termine if there was a difference in the limbus-insertion distance in the lateral rectus muscle in esotropia compared with exotro pia. The average insertion distance of 32 lat eral rectus muscles in patients with esotropia was 6.42 mm, compared with 6.47 mm in 41 cases of exotropia. This difference was not significant. The average insertion distance of 43 medial rectus muscles in patients with esotropia was 4.91 mm, compared with 5.32 mm in 29 cases with exotropia. This did rep resent a significant difference (p < 0.001) (table 3). Cases were then grouped according to the size of the deviation as measured for dis tance and near. Deviations were defined as small if the largest deviation was 45Δ or less, and large if the largest deviation was 60Λ or more. Comparisons were made of the medial rectus muscle insertions in (1) small versus large exotropia and (2) small versus large esotropia. Statistically, no significant differ-
TABLE 3 LLMBUS-INSERTION DISTANCE ESOTROPIA VERSUS EXOTROPIA
Significance of Difference
No. of Muscles
Average I nsertion (mm)
Medial Rectus Esotropia Exotropia
43 29
4.91 5.32
Yes
Lateral Rectus Esotropia Exotropia
32 41
6.42 6.47
None ( p > 0 . 0 5 )
(p<0.001)
VOL. 68, N O . 4
INSERTION OF RECTUS MUSCLES
697
TABLE 4 M E D I A L RECTUS: LIMBUS-INSERTION DISTANCE SMALL VERSUS LARGE DEVIATIONS
No. of Muscles
Average Insertion (mm)
Significance of Difference
Esotropia Small (45Δ or less) Large (60Δ or more)
20 20
5.OS 4.90
None ( p > 0 . 0 5 )
Exotropia Small (45Δ or less) Large (60Δ or more)
9 9
5.40 5.39
None ( p > 0 . 0 5 )
enee was noted (table 4). Similarly, no sig nificant difference was found in the inser tion distance of the lateral rectus muscle in small compared with large esotropia, and in small compared with large exotropia (table 5). The insertion distances of the medial and lateral rectus muscles in cases operated upon for the A and V pattern were examined. No significant differences were found in the in sertions of the medial rectus or the lateral
rectus muscles in cases with and without the A and V patterns (table 6 ) . In those cases in which both eyes were op erated upon, the medial rectus insertion of one eye was compared with that of the fel low eye. A similar comparison was made be tween the two lateral rectus muscles. Analy sis indicated that for both the medial rectus and the lateral rectus, the insertion distance of the two eyes differed significantly, but not in any predictable direction or relationship.
TABLE 5 LATERAL RECTUS: LIMBUS-INSERTION DISTANCE SMALL VERSUS LARGE DEVIATIONS
No. of Muscles
Average Insertion (mm)
Significance of Difference
Esotropia Small (45Δ or less) Large (60Δ or more)
13 14
6.41 6.49
None ( p > 0 . 0 5 )
Exotropia Small (45Δ or less) Large (60Δ or more)
23 10
6.53 6.55
None ( p > 0 . 0 5 )
TABLE 6 LIMBUS INSERTION DISTANCE A-V PATTERNS
No. of Muscles
Average Insertion (mm)
Significance of Difference
Medial Rectus A-V pattern No A-V pattern
10 54
5.32 5.00
None ( p > 0 . 0 5 )
Lateral Rectus A-V pattern No A-V pattern
15 48
6.51 6.43
None ( p > 0 . 0 5 )
698
AMERICAN JOURNAL OF OPHTHALMOLOGY DISCUSSION
The limbus-insertion distance in patients with strabismus was compared with a se ries of routine autopsy eyes; only the measurements of the medial rectus muscle were significantly smaller. In addition, the limbus-insertion distance of the medial rec tus was significantly smaller in patients with esotropia compared with patients with exotropia. There was no significant difference in the lateral rectus muscle measurements in esotropia compared with exotropia. No sig nificant relationship was found between these measurements and either the size of the deviation or the presence of the A and V pattern. Since the medial rectus muscle inserts sig nificantly closer to the limbus in cases of esotropia, it would seem that the site of in sertion of this muscle may play a part in the etiology of esotropia and that greater varia tion in response to surgery in esotropia may be expected. The significant difference in the insertion of the medial and lateral rectus muscles in one eye as compared with that of the fellow eye, however, makes it almost im possible to use these measurements as an in dication for the type and amount of surgery since the insertion distance of each of the
OCTOBER, 1969
four horizontal muscles is required in order to make this information useful. SUMMARY
The limbus-insertion distance of the me dial and lateral rectus muscles in a series of eyes operated on for strabismus was com pared with similar measurements reported in normal eyes. Analysis was made to deter mine relationship between these measure ments and the clinical findings. ACKNOWLEDGMENT
I thank Mrs. Aurora Clahane for assistance in the preparation of statistical analysis. REFERENCES
1. Scobee, R. G. : The Oculorotary Muscles. St. Louis, Mosby, 1947, ed. 2, p. 34. 2. Wolff, E. : The Anatomy of the Eye and Orbit. New York, McGraw-Hill, 1968, p. 256. 3. Fink, W. H. : The Anatomy of the Extrinsic Muscles of the Eye. Strabismus : Ophthalmic Sym posium II. (J. H. Allen, ed.) St. Louis, Mosby, 1958, p. 53. 4. Fuchs, E. : Beitrage zur normalen Anatomie des Augapfels. Arch. f. Ophth. 30 (4) :1, 1884. 5. von Gar, L. : Ein Beitrag zur Topographie des Ansatzes der vier geraden Augenmuskeln. Ophthalmologica 114:43, 1947. 6. Scobee, R. G. : Anatomie factors in the etiol ogy of heterotropia. Am. J. Ophth. 31:781, 1948. 7. Duke-Elder, S. : System of Ophthalmology. St. Louis, Mosby, 1961, p. 81.
OPHTHALMIC MINIATURE
Should the eyelids be glued together on awakening in the morning, the patient is not to attempt to open them by force, but is to soften the con cretion by means of a little warm water, or warm milk and water. He will then be able, not only to seperate the lids without difficulty, but also to remove such concretion without either pain or injury. If, instead of this, the patient should attempt to open them by force, he will be sure to pull out some of the lashes, and thus will not only aggravate the inflam mation at their roots, but will most probably injure, or even destroy, so much of the structure of the bulbs, as to arrest the lashes in their growth, and render them ever after, feeble, stunted, and irregular. Cooper, William White : Practical Remarks on New Sight, Aged Sight, and Impaired Vision. London, John Churchill, 1847.
EFFERENT FIBERS
VOL. 68, NO. 4
which formed normal radiations. The calcarine cortex was normal. ADDENDUM
Since this manuscript was submitted for publica tion, a significant article has appeared in the lit erature (Haberland, C. and Pérou, M. : Primary bilateral anophthalmia. J. Neuropath. Exp. Neurol. 28:337, 1969). The authors describe a patient in whom no ocular tissue was found in the orbits, and in whom the optic nerves, chiasm and optic tracts were totally absent. The lateral geniculate bodies were dysplastic and atrophie, the optic radiations were absent, the visual cortex was small and the stripe of Gennari was absent.
REFERENCES
1. Honrubia, F. M. and Elliott, J. H. : Efferent innervation of the retina: I. Morphologic study of the human retina. Arch. Ophth. 80:98, 1968. 2. Wolter, J. R. : The centrifugal nerves in the human optic tract, chiasm, optic nerve and retina. Tr. Am. Ophth. Soc. 63 :678, 1965. 3. Mann, I. : Developmental Abnormalities of the Eye. Philadelphia, Lippincott, 1957, ed. 2, p. 66. 4. Wolter, J. R. and Lund, O. E.: Reaction of centrifugal nerves in the human retina : Two weeks after photocoagulation. Am. J. Ophth. 66:221, 1968. 5. Mann, I. : The Development of the Human Eye. New York, Grune and Stratton, 1964, ed. 3, p. 143.
STRABISMUS AND I N S E R T I O N O F H O R I Z O N T A L RECTUS MUSCLES JOSEPH H.
GOLDSTEIN,
M.D.
Brooklyn, New York
The distance from the limbus to the inser tion of the lateral and the medial rectus mus cles is given by most standard textbooks1"3 as 6.9 mm and 5.5 mm, respectively. These measurements, based on a series of enucle ated eyes, were reported by Fuchs 4 in 1884. After reviewing previous publications, Gat5 reported on a series of cadaver eyes in which he measured the distance from the limbus to the insertion of the horizontal rectus mus cles. These measurements represented essen tially normal eyes. In view of the assertion by Scobee6 that 90% of all cases of heterotropia have some underlying anatomic basis, and the fact that the accepted measurements represent essentially normal eyes, the present study was undertaken to determine the varia tion in the limbus-insertion distance of the lateral and of the medial rectus muscles in eyes with strabismus and to evaluate its rela tion, if any, to the clinical findings. From the Division of Ophthalmology, Depart ment of Surgery, Downstate Medical Center, State University of New York. This paper was presented in part at the Annual Alumni Meeting, State Uni versity of New York, Downstate Medical Center. Reprint requests to Joseph H. Goldstein, M.D., Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, New York 11203.
MATERIALS AND METHODS
All measurements were made at the time of surgery in patients operated upon for strabismus. After the muscle was cut from the globe, one arm of the caliper was placed at the midpoint of the base of the insertion of the muscle and the distance was measured to the limbus on a line perpendicular to the in sertion. All measurements were made on the medial or lateral rectus muscles. The limbus was considered the junction of opaque sclera with cornea. Measurements were made to the nearest 0.2 mm. RESULTS
A total of 64 patients were included in this study. Measurements were taken on 72 medial rectus and 73 lateral rectus muscles. The medial rectus muscle insertion ranged from 3.5 mm to 6.0 mm, and that of the lat eral rectus muscle from 4.5 mm to 8.0 mm. These measurements were compared with those of Gat who performed the same mea surements on 80 adult cadaver eyes. The av erage limbus-insertion distance of the medial rectus was 5.07 mm in the present study and 5.40 mm in Gat's study. The average lim bus-insertion distance of the lateral rectus
696
AMERICAN JOURNAL OF OPHTHALMOLOGY
OCTOBER, 1969
TABLE 1 LLMBUS-INSERTION DISTANCE NORMAL VERSUS STRABISMUS Goldstein
Rectus Muscle
No. of Muscles
T
72 73
Medial Lateral
Aver I n
t^
™ (mm)
n
5.07 6.45
TABLE 2 AGE DISTRIBUTION
Age (yr)
No. of Patients
Under 3 3-13 14 and over
6 43 15
TOTAL
64
was 6.44 mm in this study and 6.61 mm in Gat's study. Statistical analysis indicates that for the lateral rectus muscle the difference between the two series (0.17 mm) is not sig nificant but that for the medial rectus this difference (0.33 mm) is highly significant (p < 0.01) (table 1). It might be suggested that an accurate analysis cannot be made because of the difference in age between the subjects in Gat's series and the patients in the present study. The age distribution of the latter is shown in Table 2. Since the eye attains over 95% of its adult size by the age of three,7 and since only eight measurements were in cluded on patients under three years of age, these comparisons were considered accept-
Gat
Muscles
Insertion (mm)
Aver™
Significance of Difference
80 80
5.40 6.61
Yes p < 0 . 0 1 None p > 0 . 0 5
No. of
e
able. The data was reanalyzed, however, ex cluding these eight values; the results were the same. The measurements were analyzed to de termine if there was a difference in the limbus-insertion distance in the lateral rectus muscle in esotropia compared with exotro pia. The average insertion distance of 32 lat eral rectus muscles in patients with esotropia was 6.42 mm, compared with 6.47 mm in 41 cases of exotropia. This difference was not significant. The average insertion distance of 43 medial rectus muscles in patients with esotropia was 4.91 mm, compared with 5.32 mm in 29 cases with exotropia. This did rep resent a significant difference (p < 0.001) (table 3). Cases were then grouped according to the size of the deviation as measured for dis tance and near. Deviations were defined as small if the largest deviation was 45Δ or less, and large if the largest deviation was 60Λ or more. Comparisons were made of the medial rectus muscle insertions in (1) small versus large exotropia and (2) small versus large esotropia. Statistically, no significant differ-
TABLE 3 LLMBUS-INSERTION DISTANCE ESOTROPIA VERSUS EXOTROPIA
Significance of Difference
No. of Muscles
Average I nsertion (mm)
Medial Rectus Esotropia Exotropia
43 29
4.91 5.32
Yes
Lateral Rectus Esotropia Exotropia
32 41
6.42 6.47
None ( p > 0 . 0 5 )
(p<0.001)
VOL. 68, N O . 4
INSERTION OF RECTUS MUSCLES
697
TABLE 4 M E D I A L RECTUS: LIMBUS-INSERTION DISTANCE SMALL VERSUS LARGE DEVIATIONS
No. of Muscles
Average Insertion (mm)
Significance of Difference
Esotropia Small (45Δ or less) Large (60Δ or more)
20 20
5.OS 4.90
None ( p > 0 . 0 5 )
Exotropia Small (45Δ or less) Large (60Δ or more)
9 9
5.40 5.39
None ( p > 0 . 0 5 )
enee was noted (table 4). Similarly, no sig nificant difference was found in the inser tion distance of the lateral rectus muscle in small compared with large esotropia, and in small compared with large exotropia (table 5). The insertion distances of the medial and lateral rectus muscles in cases operated upon for the A and V pattern were examined. No significant differences were found in the in sertions of the medial rectus or the lateral
rectus muscles in cases with and without the A and V patterns (table 6 ) . In those cases in which both eyes were op erated upon, the medial rectus insertion of one eye was compared with that of the fel low eye. A similar comparison was made be tween the two lateral rectus muscles. Analy sis indicated that for both the medial rectus and the lateral rectus, the insertion distance of the two eyes differed significantly, but not in any predictable direction or relationship.
TABLE 5 LATERAL RECTUS: LIMBUS-INSERTION DISTANCE SMALL VERSUS LARGE DEVIATIONS
No. of Muscles
Average Insertion (mm)
Significance of Difference
Esotropia Small (45Δ or less) Large (60Δ or more)
13 14
6.41 6.49
None ( p > 0 . 0 5 )
Exotropia Small (45Δ or less) Large (60Δ or more)
23 10
6.53 6.55
None ( p > 0 . 0 5 )
TABLE 6 LIMBUS INSERTION DISTANCE A-V PATTERNS
No. of Muscles
Average Insertion (mm)
Significance of Difference
Medial Rectus A-V pattern No A-V pattern
10 54
5.32 5.00
None ( p > 0 . 0 5 )
Lateral Rectus A-V pattern No A-V pattern
15 48
6.51 6.43
None ( p > 0 . 0 5 )
698
AMERICAN JOURNAL OF OPHTHALMOLOGY DISCUSSION
The limbus-insertion distance in patients with strabismus was compared with a se ries of routine autopsy eyes; only the measurements of the medial rectus muscle were significantly smaller. In addition, the limbus-insertion distance of the medial rec tus was significantly smaller in patients with esotropia compared with patients with exotropia. There was no significant difference in the lateral rectus muscle measurements in esotropia compared with exotropia. No sig nificant relationship was found between these measurements and either the size of the deviation or the presence of the A and V pattern. Since the medial rectus muscle inserts sig nificantly closer to the limbus in cases of esotropia, it would seem that the site of in sertion of this muscle may play a part in the etiology of esotropia and that greater varia tion in response to surgery in esotropia may be expected. The significant difference in the insertion of the medial and lateral rectus muscles in one eye as compared with that of the fellow eye, however, makes it almost im possible to use these measurements as an in dication for the type and amount of surgery since the insertion distance of each of the
OCTOBER, 1969
four horizontal muscles is required in order to make this information useful. SUMMARY
The limbus-insertion distance of the me dial and lateral rectus muscles in a series of eyes operated on for strabismus was com pared with similar measurements reported in normal eyes. Analysis was made to deter mine relationship between these measure ments and the clinical findings. ACKNOWLEDGMENT
I thank Mrs. Aurora Clahane for assistance in the preparation of statistical analysis. REFERENCES
1. Scobee, R. G. : The Oculorotary Muscles. St. Louis, Mosby, 1947, ed. 2, p. 34. 2. Wolff, E. : The Anatomy of the Eye and Orbit. New York, McGraw-Hill, 1968, p. 256. 3. Fink, W. H. : The Anatomy of the Extrinsic Muscles of the Eye. Strabismus : Ophthalmic Sym posium II. (J. H. Allen, ed.) St. Louis, Mosby, 1958, p. 53. 4. Fuchs, E. : Beitrage zur normalen Anatomie des Augapfels. Arch. f. Ophth. 30 (4) :1, 1884. 5. von Gar, L. : Ein Beitrag zur Topographie des Ansatzes der vier geraden Augenmuskeln. Ophthalmologica 114:43, 1947. 6. Scobee, R. G. : Anatomie factors in the etiol ogy of heterotropia. Am. J. Ophth. 31:781, 1948. 7. Duke-Elder, S. : System of Ophthalmology. St. Louis, Mosby, 1961, p. 81.
OPHTHALMIC MINIATURE
Should the eyelids be glued together on awakening in the morning, the patient is not to attempt to open them by force, but is to soften the con cretion by means of a little warm water, or warm milk and water. He will then be able, not only to seperate the lids without difficulty, but also to remove such concretion without either pain or injury. If, instead of this, the patient should attempt to open them by force, he will be sure to pull out some of the lashes, and thus will not only aggravate the inflam mation at their roots, but will most probably injure, or even destroy, so much of the structure of the bulbs, as to arrest the lashes in their growth, and render them ever after, feeble, stunted, and irregular. Cooper, William White : Practical Remarks on New Sight, Aged Sight, and Impaired Vision. London, John Churchill, 1847.