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SYNOPTOPHORE There are many vers

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					                     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 after-
                                 images).

                                 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 first-
grade 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 cyclo-
deviation is present. If the cage's left-
hand 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
                     45 to 80mm
   distance
   Chinrest
   height(from       60 to 130mm
   eyepiece tube)
   Standard
                     13sets
   slides
   Flashing count
                     10 to 400 times
   of automatic
                     per minute
   flashing device
   Manual            Push button
   flashing device   operation
   Revolution of     50 to
Heidenger's      100revolution
brushes'         per minute
device
                 Visual field
Stepless
                 (angle)
diaphragm
                 adjustment
Taget
illumination     6.2V0.3A bulb
lamp
After Image
                 12V2A bulb
lamp
                 530mm(W) x
Dimensions       310mm(D) x
                 390mm(H)
Weight           20kgs




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