- Email: [email protected]
Sixth-Nerve Palsy
899
NOTES, CASES, I N S T R U M E N T S
back to t w o meters and the area thoroughly
A b o u t 500 field examinations have been
object
performed with this instrument, and it has
visible. T h e illumination is suitably increased
been found without exception to reduce the
by re-setting the shutter lever to a calibrated
time to less than one-half o f that formerly
re-explored
with
the
smallest
test
required. Responses have been more prompt,
position. Color fields are plotted if desired. T h e
definite, and consistent, and patients w h o
isopters are completed by lines drawn be
were accustomed to the old method have
tween consecutive points. It is gratifying to
been generous with unsolicited comments.
find that with this instrument very little addi
T h e usual feeling is one o f increased confi
tional time is required to locate twice the
dence in their o w n responses, decreased ten
usual number of points, which further
au
sions,
and
general
satisfaction
at
having
completed the test so quickly and pleasantly.
thenticates any pathologic finding.
REFERENCES
Chamlin, M . : Recording of visual fields. Am. J. Ophth., 31:565 ( M a y ) 1948. Cordes, F. C.: Perimetry in glaucoma: A plea for better instruction. Am. J. Ophth., 32:145 (Jan.) 1949. Gaines, S. R . : The value of central field studies over the conventional type of field studies. New Orleans M. & Surg. J., Oct., 1944, pp. 97-176. Peter, L. C.: Principles and Practice of Perimetry. Philadelphia, Lea, 1916. Traquair, H . M . : An Introduction to Clinical Perimetry. St. Louis, Mosby, 1949. Vail, D . : Perimetry. Am. J. Ophth., 30:1182 (Sept.) 1947.
the fact that the patient insisted on having
SIXTH-NERVE PALSY
the normal left eye occluded. She was unable W I T H
PAST-POINTING
E.
HOWARD
T O T H E OPPOSITE
BEDROSSIAN,
SIDE
lyzed right eye could not be explained by a
Philadelphia, Pennsylvania
M r s . L. I., a 62-year-old white woman, was admitted to the graduate hospital on D e cember S, 1953, o n the service o f D r . E d ward Gosfield, because o f double vision. A n eye consultation showed a classic right sixthnerve palsy with primary and secondary de viation. T h e patient had n o diplopia o n look ing to the left but had diplopia in eyes front, which increased on right lateral gaze. T h e right eye could be rotated only a short dis tance past
the
midline. T h e patient
to get around i f the paralytic right eye was occluded. H e r preference f o r using the para
M.D.
also
showed a grade-II hypertensive retinopathy.
visual defect in the normal left eye. T h e patient was then tested for absolute
her normal left eye was covered and she fixed with the paralyzed right eye, she did not past-point or past-walk at all. H o w e v e r , if the paralyzed right eye was covered and the normal left eye used f o r
fixation,
left. This obviously was the reason she in sisted on having her normal eye occluded. There seems to be very little written re garding an explanation
visual fields were normal.
A d l e r in his textbook. Physiology
neurologic examination was negative
the
patient past-pointed and past-walked to the
Corrected vision was 6 / 6 in each eye and A
(ego
centric) localization. It was found that, if
Eye,
for
past-pointing. of
the
states " T h e direction o f past-pointing
except for the right sixth-nerve palsy. A
is always in the direction o f action o f a
thorough medical survey showed a diabetic
paretic muscle." H e then goes on to give
type glucose tolerance curve and hyperten
two possible explanations f o r past-pointing.
sive cardiovascular disease manifested by a
O n e is based o n an excessive innervation to
blood pressure o f 1 7 0 / 1 1 0 mm. H g . T h e unusual feature about this case was
the paralytic muscle, giving the
sensation
that the object is farther to the right ( i n a
900
NOTES, CASES, I N S T R U M E N T S
right sixth-nerve palsy) than it really is, and hence the patient past-points. T h e second explanation is based on the fact that an o b ject in the right temporal field (in a case o f right lateral rectus palsy) will not fall on the fovea o f the right eye but on a nasal retinal element o f that eye. Since the nasal ret inal elements have local signs in the tem poral field, the object is interpreted as being farther in the temporal field than it really is. Therefore, the subject past-points to that p o sition in space which corresponds to the local sign of the part o f the retina stimulated. Dr. Adler showed by certain experiments, using a large and small spotlight on a perimeter, that the angle of past-pointing is determined by the position of the image on the retina, and he concludes "It is not necessary, therefore, to account for past-pointing by assuming abnormal proprioception o f the ocular mus cles." In the present case neither o f these e x planations would account for the past-point ing to the opposite side with the normal eye fixing. Therefore, Bárány and caloric tests were ordered to determine the integrity o f the vestibular apparatus and median longitu dinal fasciculus. T h e report came back "def initely no posterior fossa lesion."
TRANSILLUMINATING ATTACHMENT FOR A PENLIGHT ALFRED A . NISBET, M . D .
San Antonio, Texas This transilluminating attachment is a modified eyedropper bulb. T h e larger end fits snugly over the bulb socket o f the penlight as shown in Figure 1. T h e small end has an opening about five mm. in diameter. Through this opening, the beam o f light emerges. T h e rubber tip makes sufficiently good contact with the bulbar conjunctiva so that little light escapes. M o s t o f the light is directed into the eye through the sclera and adequate transillumination is obtained. Not enough heat is generated by the bulb during each contact period to be significant. This cap may be removed from the light with ease and sterilized by cold solution or by boiling water. Usually a surface anesthetic is instilled prior to touching the globe. This is not entirely necessary, for most patients do not object when the bulbar conjunctiva is touched with this soft tip.
The patient was put on a diet for her latent diabetes. T w o months later she had completely recovered from the sixth-nerve palsy. She did not past-point o r past-walk with either eye fixing while the other eye was occluded. This case is o f unusual interest for two reasons: First, it was not possible to find any sim ilar case reported in the literature. Second, the usual reasons given f o r pastpointing certainly would not explain this bizarre case in which the past-pointing o c curred to the opposite side when the normal eye was fixing. 2027 Spruce Street (3).
Fig.
1 (Nisbet). Transilluminating attachment for a penlight.
I have used this simple but adequate transilluminator for five years and have found it a convenient device, particularly for home or hospital examinations. 700 South
McCullough.
NOTES, CASES, I N S T R U M E N T S
back to t w o meters and the area thoroughly
A b o u t 500 field examinations have been
object
performed with this instrument, and it has
visible. T h e illumination is suitably increased
been found without exception to reduce the
by re-setting the shutter lever to a calibrated
time to less than one-half o f that formerly
re-explored
with
the
smallest
test
required. Responses have been more prompt,
position. Color fields are plotted if desired. T h e
definite, and consistent, and patients w h o
isopters are completed by lines drawn be
were accustomed to the old method have
tween consecutive points. It is gratifying to
been generous with unsolicited comments.
find that with this instrument very little addi
T h e usual feeling is one o f increased confi
tional time is required to locate twice the
dence in their o w n responses, decreased ten
usual number of points, which further
au
sions,
and
general
satisfaction
at
having
completed the test so quickly and pleasantly.
thenticates any pathologic finding.
REFERENCES
Chamlin, M . : Recording of visual fields. Am. J. Ophth., 31:565 ( M a y ) 1948. Cordes, F. C.: Perimetry in glaucoma: A plea for better instruction. Am. J. Ophth., 32:145 (Jan.) 1949. Gaines, S. R . : The value of central field studies over the conventional type of field studies. New Orleans M. & Surg. J., Oct., 1944, pp. 97-176. Peter, L. C.: Principles and Practice of Perimetry. Philadelphia, Lea, 1916. Traquair, H . M . : An Introduction to Clinical Perimetry. St. Louis, Mosby, 1949. Vail, D . : Perimetry. Am. J. Ophth., 30:1182 (Sept.) 1947.
the fact that the patient insisted on having
SIXTH-NERVE PALSY
the normal left eye occluded. She was unable W I T H
PAST-POINTING
E.
HOWARD
T O T H E OPPOSITE
BEDROSSIAN,
SIDE
lyzed right eye could not be explained by a
Philadelphia, Pennsylvania
M r s . L. I., a 62-year-old white woman, was admitted to the graduate hospital on D e cember S, 1953, o n the service o f D r . E d ward Gosfield, because o f double vision. A n eye consultation showed a classic right sixthnerve palsy with primary and secondary de viation. T h e patient had n o diplopia o n look ing to the left but had diplopia in eyes front, which increased on right lateral gaze. T h e right eye could be rotated only a short dis tance past
the
midline. T h e patient
to get around i f the paralytic right eye was occluded. H e r preference f o r using the para
M.D.
also
showed a grade-II hypertensive retinopathy.
visual defect in the normal left eye. T h e patient was then tested for absolute
her normal left eye was covered and she fixed with the paralyzed right eye, she did not past-point or past-walk at all. H o w e v e r , if the paralyzed right eye was covered and the normal left eye used f o r
fixation,
left. This obviously was the reason she in sisted on having her normal eye occluded. There seems to be very little written re garding an explanation
visual fields were normal.
A d l e r in his textbook. Physiology
neurologic examination was negative
the
patient past-pointed and past-walked to the
Corrected vision was 6 / 6 in each eye and A
(ego
centric) localization. It was found that, if
Eye,
for
past-pointing. of
the
states " T h e direction o f past-pointing
except for the right sixth-nerve palsy. A
is always in the direction o f action o f a
thorough medical survey showed a diabetic
paretic muscle." H e then goes on to give
type glucose tolerance curve and hyperten
two possible explanations f o r past-pointing.
sive cardiovascular disease manifested by a
O n e is based o n an excessive innervation to
blood pressure o f 1 7 0 / 1 1 0 mm. H g . T h e unusual feature about this case was
the paralytic muscle, giving the
sensation
that the object is farther to the right ( i n a
900
NOTES, CASES, I N S T R U M E N T S
right sixth-nerve palsy) than it really is, and hence the patient past-points. T h e second explanation is based on the fact that an o b ject in the right temporal field (in a case o f right lateral rectus palsy) will not fall on the fovea o f the right eye but on a nasal retinal element o f that eye. Since the nasal ret inal elements have local signs in the tem poral field, the object is interpreted as being farther in the temporal field than it really is. Therefore, the subject past-points to that p o sition in space which corresponds to the local sign of the part o f the retina stimulated. Dr. Adler showed by certain experiments, using a large and small spotlight on a perimeter, that the angle of past-pointing is determined by the position of the image on the retina, and he concludes "It is not necessary, therefore, to account for past-pointing by assuming abnormal proprioception o f the ocular mus cles." In the present case neither o f these e x planations would account for the past-point ing to the opposite side with the normal eye fixing. Therefore, Bárány and caloric tests were ordered to determine the integrity o f the vestibular apparatus and median longitu dinal fasciculus. T h e report came back "def initely no posterior fossa lesion."
TRANSILLUMINATING ATTACHMENT FOR A PENLIGHT ALFRED A . NISBET, M . D .
San Antonio, Texas This transilluminating attachment is a modified eyedropper bulb. T h e larger end fits snugly over the bulb socket o f the penlight as shown in Figure 1. T h e small end has an opening about five mm. in diameter. Through this opening, the beam o f light emerges. T h e rubber tip makes sufficiently good contact with the bulbar conjunctiva so that little light escapes. M o s t o f the light is directed into the eye through the sclera and adequate transillumination is obtained. Not enough heat is generated by the bulb during each contact period to be significant. This cap may be removed from the light with ease and sterilized by cold solution or by boiling water. Usually a surface anesthetic is instilled prior to touching the globe. This is not entirely necessary, for most patients do not object when the bulbar conjunctiva is touched with this soft tip.
The patient was put on a diet for her latent diabetes. T w o months later she had completely recovered from the sixth-nerve palsy. She did not past-point o r past-walk with either eye fixing while the other eye was occluded. This case is o f unusual interest for two reasons: First, it was not possible to find any sim ilar case reported in the literature. Second, the usual reasons given f o r pastpointing certainly would not explain this bizarre case in which the past-pointing o c curred to the opposite side when the normal eye was fixing. 2027 Spruce Street (3).
Fig.
1 (Nisbet). Transilluminating attachment for a penlight.
I have used this simple but adequate transilluminator for five years and have found it a convenient device, particularly for home or hospital examinations. 700 South
McCullough.