Download SYNOPTOPHORE There are many versions of the major

SYNOPTOPHORE
There are many versions of the major
amblyoscope; the most widely used
are the synoptophore and the
troposcope.
In this search we will discuses only the
synoptophore; the major amblyoscope
can be used for both sensory and
motor evaluation.
What is Synaptophore?
The synaptophore is a basic orthoptic
instruments useful especially in the
study of the sensory status of the
patient and a nonsurhical treatment.
Synaptophore Consist Of
1/ Chinrest.
2/Foreheadrest.
3/ two tubes:
At outer end of each tube there is a
slide carrier into which pictures are
inserted and seen through an angled
eyepiece , one for each eye(so that
each eye is stimulated by a separate
image). The total length of the tube is
equal to the focal length of the lens.
The slides are located at the focal
distance of a +6.50D or +7.00D convex
lens. The emergent rays are parallel
and no accommodation is required by
the patient.
These tubes is placed horizontally and
supported by a column around which
they are movable in the horizontal
plane.
The distance between the tubes can be
adjusted. So that the canters of the
eyepieces correspond accurately to the
interpupillary distance of the patient.
When this is done and if the head and
chin are properly adjusted, the axes
around which the tubes turn should be
in line with the center oh rotation of the
eyes.
The tubes may be locked together, so
that they may be moved together
horizontally and in some modern also
vertically.
4/Controls:
Allow a vertical separation of the
targets as well cyclorotational
adjustment.
5/Mirror:
One in each tube to reflects the image
of target through the eyepiece into
corresponding eye.
6/Scales:
To read the amount of displacement.
Usually, they are graduated both in arc
degrees and prism dioptres.
7/Illumination system:
For each target can be individually
controlled to increase or decrease the
stimulus luminance to one eye if
desired
(A low-intensity light source for the
illumination of the slides, and a high –
intensity light source for creating afterimages).
8/Keys:
Provided for manual flashing of the
light illuminating either target. The
flashing can also be controlled
automatically in certain models, with
wide range of light-dark intervals.
This instrument may be equipped with
a greater or lesser number of
refinements.
Some models have provisions for the
production of afterimage. And some of
those contain a device called
Haidinger's brushes, which is
employed to test macular function and
projection.
This instrument used for diagnostic or
therapeutic purposes.
The Diagnostic Uses Of The
Synoptophore:
1/Measurement of the objective and
subjective angle of deviation.
2/Measurement of angle kappa.
3/Measurement of primary and
secondary deviation.
4/Measurement of deviation in cardinal
directions of gaze.
5/Estimation of status of binocular:
a. state of retinal correspondence:
normal, abnormal.
b.presence and type of suppression.
c.presence of fusion and measurement
of fusional amplitudes.
d.presence of stereopsis.
And to assess the grades of binocular
vision, different targets are presented
to the eye:
Grade (1): binocular vision requires
simultaneous perception (parafoveal,
foveal, or macular slides may be used;
this choice depends on V/A).
Dissimilar targets, such as a lion and
cage, are presented to each eye.
The patient who sees the lion in the
cage is seeing with each eye
simultaneously and has grade 1
binocular vision.
If suppression is present, one image
disappears intermittently. The "jump"
is caused by disappearance of an
image and therefore is repetitious.
Grade (2): binocular vision requires
fusional ability.
Similar targets presented to each eye
must be fused before a complete
picture is identified. a grade 2 target
may present to one eye a picture of a
rabbit with no tail , clutching flowers ,
the other eye would be presented with
a picture of the same rabbit , but it
would have a tail , and geld in its hand
would be a stem without flowers.
Grade 2 binocular vision is present if
the patient fuses these images and
reports seeing a tailed rabbit clutching
a group of flowers by a stem.
If the patient has suppression, in of the
controls (the tail or flowers) will
disappear.
With grade 2 targets, fusional reserves
can be measured by moving the arms
of the instrument in or out (fusional
convergence and divergence) until a
point is reached where the patient
complains of diplopia (sees tow
rabbits) or suppression (flowers or tail
disappear) at the break point.
Grade (3): depth perception:
Binocular vision requires the
coordinate use of the two eyes
together to yield the sensation of
stereopis.
Grade 3 slides present to the viewer
pictures that are not quite
superimposable .the fusion of these
slightly disparate images by the brain
creates the sensation of depth, or
stereopis .if fused correctly, one of the
seahorses will appear distinctly in front
of the others.
The Therapeutic Uses of The
Synoptophore:
It is used in the treatment of:
1/Suppression.
2/Abnormal retinal correspondence.
3/Eccentric fixation (only in models
that have special attachments with
Haidinger brushes).
4/Accommodative esotropia
(dissociation training).
5/Heterophorias and intermittent
heterotopias (improvement of fusional
amplitudes
Measurement of The Angle of Deviation
For Near by The Synoptophore:
Minus 3.00D spheres can be inserted in
the lens holders situated in front of the
eyepiece lenses. The patient has to
exert 3.00D of accommodation in order
to get a clear image of the slides. In
doing so , each eye exerts 3Δ of
convergence for each dioptre of
accommodation-in other words, 9Δ of
convergence in one eye or 18Δ of
convergence, in both eyes-considering
the interpupillary distance as being
60mm.(for a smaller interpupillary
distance, the convergence requirement
is less; for a bigger one it is more,
providing the AC/A ratio is normal
).when recording the angle of
deviation, we must keep this in mind
and either subtract 18Δ from or add
18Δ to the major amblyoscope
readings). In other words, a major
amblyoscope recording of 20Δ BO will
be recorded as 2Δ ET, while a reading
of 20ΔBI will be recorded as 38Δ XT.
Measurement of the Objective Angle by
The Synoptophore:
After making sure that the patient is
comfortably seated and correctly
positioned in front of the instrument,
we adjust it for the patient's
interpupillary distance and insert firstgrade targets (dissimilar targets, for
example, the lion and the cage) into the
slide holders. The arms of the
instrument are unlocked. The lion is
placed in front of the fixing eye (the
right eye) and the light in front of the
left eye is turned off. The right arm is
set at zero and the left one in the
vicinity of zero on the base-out side for
esodeviations or on the base-in side
for exodeviations. After making sure
that the patient is accurately fixing the
lion, the light in front of the left eye is
turned on and the light in front of the
right eye turned off. The patient is
asked to look directly into the centre of
the cage. If the left eye moves out to
pick up fixation, the left arm is moved
into a more convergent, or less
divergent, position. If the eye moves in,
the arm is moved into a more
divergent, or less convergent, position.
If the eye moves downward the tube
gas to be raised; if it moves upward the
tube has to be lowered. The alternate
flashing is continued and the tube
adjusted until there is no movement in
either eye when it picks up fixation.
The reading on the horizontal scale in
front of the left arm, as well as the one
of the vertical scale, represents the
objective angle of deviation. For
instance, if the left arm is at 15Δ BO
and has to be raised 2Δ, the objective
angle is recorded as 15Δ ET and 2Δ
LHT. The objective angle can be
measured with either eye fixing and in
all cardinal directions of gaze.
Measurement of Subjective Angle of
Deviation:
If the patient claims superimposition
(the lion is the cage) at his objective
angle, this angle is also his subjective
one. If this is not the case, the arms are
moved back to zero and the patient is
instructed to fixate steadily on the lion
while he is moving the left arm until the
lion is in cage. This is his subjective
angle. At this point, the orthoptist
should, by means of rapid alternate
flashing, check whether or not the eyes
move when the patient is asked to
fixate on each picture in turn. This is
done mainly to mainly to make sure
that an actual change in the angle
between the visual axes has not
occurred, as happens frequently
through relaxing or increasing the
accommodative effort or in cases of a
variable angle of deviation. In the
majority of cases the determination of
the subjective angle is not as simple as
described previously. The patient may
never succeed in putting the lion in the
cage, and it may suddenly be seen on
the other side of the cage (in a crossed
or heteronymous position in divergent
deviations), or there may be too much
suppression. In such cases the
crossing point is considered to be the
subjective angle.
Determination of angle of anomaly:
The difference between the objective
angle and the subjective angle
represents the angle of anomaly. For
instance, if a patient with convergent
strabismus has an objective angle of
deviation of 20ΔBO and a subjective
angle of 6ΔBO, his angle of anomaly is
14Δ.
Determination of The Angle Kappa:
A special slide is placed in front of the
eye under observation. It consists of a
row of numbers and letters at 1Δ
intervals. The patient is asked to look
at the zero. If the corneal reflex is on
the nasal side of the pupil the angle is
positive; if it is on the temporal side it
is negative. The patient is asked to look
in turn at either one letter or one
number until the reflex is centred. The
degree of deviation corresponding to
the letter or number is then recorded.
For instance, if the right eye is the one
to be tested and the corneal reflex is
centred when the patient looks at the
letter C, the patient has a 3º
negative angle kappa in the right eye.
Determination of the fusional
amplitudes:
After determinating the objective angle
and the presence of first-grade
(superimposition), the examiner
introduces second-grade slides
(similar targets with control marks for
each eye). If the patient fuses these
targets and sees them as one with both
control marks (one Donald Duck with a
blue cap and a green mail bag), the
examiner blocks the arms at the
objective angle (divided equally
between both arms). Then, by means of
the horizontal vengeance controls,
both arms are first diverged and the
point where fusion breaks is recorded.
The arms are then moved back to a
less divergent position and the point
where fusion is recovered is recorded.
The examiner continues to
convergence the arms until the
patient's fusion breaks. The breaking
point is recorded, as well as the point
where it is recovered after the arms are
moved back into a less convergent
position.
There is no standardized way to record
these findings. The example given here
represents one of the numerous
possibilities:
Synoptophore test, without correction
(sc):
Distance: 26ΔET, 2ΔRHT objectively
and subjectively
Fist-and second-grade fusion at angle
Convergence to 40ΔBO/recovery at
30ΔB
Divergence to 10ΔBO/recovery at
22ΔBO.
Near (with-3.00 spheres)
46ΔET, 20ΔRHT objectively and
subjectively fist-and second-grade
fusion at angle
Convergence to 48ΔBO/ recovery at
40Δ BO
No divergence past angle, suppression
OD.
Measurement of Cyclodeviation
Objectively and Subjectively:
There is no way to carry out an
objective measurement of a
cyclodeviation. The subjective test is
done as follows:
Simultaneous perception slides are
used: the lion in front of the right eye,
the cage in front of the left eye. The
patient is asked to look at each one in
turn and is asked whether the cage
appears level. If it tilted a cyclodeviation is present. If the cage's lefthand side is lower than the right-hand
side, incyclophoria or tropia is present.
This is corrected by wheel-rotating the
slide (by means of the torsional
deviation screw) toward the patient and
the away from the orthoptist. If the
cage's right-hand side is lower than the
left-hand side, excyclophoria or tropia
is present and can be corrected by
wheel-rotating the slide away from the
patient and toward the orthoptist. The
amount of deviation is read in degrees
from the scale located on the slide
holder of the instrument. It should be
remembered that the tilt of the images
is in the opposite direction to the tilt of
the eye.
Measurement of the squint:
Two picture sides are inserted in the
carries and with the tubes set at
0º the patient is asked to look
from one to the other while each
picture is turn is illuminated.
In the event of visual axes being other
turn parallel there must be movement
of deviating eye to take up foveal
fixation of the picture presented to it.
By the same principle as the cover test
an outward movement to take up
fixation denotes a convergent position
until no further movement of the eye to
take up fixation.
The size of the deviation is then read
from the scale, indicating the arc
through which the tube has been
moved. A convergent angle is
designated and a divergent angle. By
the same method, vertical and torsional
adjustment can be made and the
measurement is taken fixing with either
eye and in all positions of gaze, in
concomitance can be accurately.
Advantages of The Synoptophore:
1/simplest to carry out.
2/enabling vertical and torsional
elements of the deviation to be
accurately assessed.
Disadvantages:
Horizontal inaccuracies may be
occurring due to convergence
accompanying the (unnecessary)
accommodative effort and patients
often exert. Thus the synoptophore
readings may show a larger convergent
or smaller divergent angle than is , in
fact, the cases
Reference:
-Orthoptics and Ocular Examination
Techniques.
Edited by
William E.Scott, M.D
Denise D.D'Agostino,C.O/C.O.T.
Leslie Weingeist Lennarson,C.O./C.O.T.
-The Ophthalmic Assistant.
Stein, H.A, Slatt, B.J& Stein, R.M. (1994)
St.Louis: Mosby-Year Book Inc.
Sixth Edition.
- Comprehensive Review of Orthoptics
and Ocular Motility.
Theory, Therapy, and Surgery
Hurt Rasicovici Windsor
-Hermann M. Burian. Hhunter K. Von
Noorden
Binocular Vision and Ocular Motility
Theory and Management of
Strabismus.
- H.T, Willoughby Casgell Isobel
M.Durran
Foreword by T.Keith Lyle C.B.E. Fourth
Edition
Handbook of Orthoptic Inciples
Churchill Livinhstone
Synoptophore
MT-364
All devices are
arrenged for easy
handling and new
wide Haidenger's
brushes' drives
rotation range and
wider automatic
flashing count range
are
provided/Examination,
exercise correction
capability:
Simultaneous
perception, fusion
streopsis, vergence,
retinal
correspondence,
monocular position,
single eye fixation
examination, removal
of suppression,
strengthened fusion,
eyeball exercise and
correction of retina.
Specifications
Pupil adjusting
distance
Chinrest
height(from
eyepiece tube)
Standard
slides
Flashing count
of automatic
flashing device
Manual
flashing device
Revolution of
45 to 80mm
60 to 130mm
13sets
10 to 400 times
per minute
Push button
operation
50 to
Heidenger's
brushes'
device
Stepless
diaphragm
Taget
illumination
lamp
After Image
lamp
Dimensions
Weight
100revolution
per minute
Visual field
(angle)
adjustment
6.2V0.3A bulb
12V2A bulb
530mm(W) x
310mm(D) x
390mm(H)
20kgs
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