The document describes a synoptophore, an instrument used to assess binocular vision. It details the parts of the synoptophore including chin rests and deviation controls, and explains how it can be used to measure properties like simultaneous perception, angle of deviation, fusion, and stereopsis. The synoptophore is a valuable tool for diagnosing binocular vision disorders and guiding related treatments.

1. Presenter
Anisha Heka, B.Optom Third year
MMC, IOM
Moderators
Dr. Sanjeev Bhattarai
Mr. Niraj Dev Joshi

2. Presentation layout
Introduction Principle Optics Parts Uses Summary

3.  Orthoptic instrument to perform
comprehensive assessment of binocular
vision.
Range or
bearing
Synoptophore
Both
Introduction

4.  Based on haploscopic principle.
 Synoptophore is designed on the principle of divisions of physical
space into two seperate area of visual space each of which is visible to
one eye only.
Principle

5.  The image of the test object slide is situated at the principle focus of the lens
 Rays of light emanating from the principle focus will, after refraction by the lens D in
the eye-piece, emerge as parallel rays; this means that an eye when viewing the image is
relaxed or focused for distance, no accommodation being required.
Optics

6. Parts of Synoptophore
Chin rest
Forehead rest Rotates tube vertically
Central lock
Horizontal deviation
control
IPD adjuster
On/Off switch
Chin Height Control
Tube light control
Tube lock
Fusion
control
Torsion
control
Slide Holder
Vertical deviation
control

7.  The eye-pieces of the tubes consist of +6.50 DS collimating lenses,
which require the patient to relax their accommodation, as if looking into
the infinite distance.
 A plane mirror reflects 90° along the two optical tubes.
 The tubes are 15.5 cm in length, so the transparencies are positioned on
the focal point of the eyepieces so that the outgoing rays are parallel and
do not require adjustment by the patient so the condition that is created
is that the images are positioned in the infinite range.
 A light source is placed at the end of the tubes, which evenly illuminates
the transparencies.

8. Uses
Diagnostic Uses of Synoptophore
1. Measurement of Simultaneous Perception (The first grade of BSV)
2. Measurement of the objective and subjective angle of deviation.
3. Measurement of the amount of deviation at near, simulating near
viewing (Accommodative convergence to accommodation ratio (AC/A
ratio)).
4. Measurement of Sensory (SF) and Motor Fusion (MF) (The second
grade of BSV)

9. 5. Measurement of Stereopsis (The third grade of BSV)
6. Measurement of the primary and secondary deviations
7. Measurement of deviation in 9 gaze positions
8. Measurement of Torsion
9. Clinical evaluation of binocular vision:
(a) retinal correspondence: normal or abnormal;
(b) presence and type of suppression;
Diagnostic Uses of Synoptophore

10. Measurement of IPD
 First step before starting any measurement of
strabismus.
 Set all the scales to zero, put the foveal
fixation and ask the patient to look to the right
picture with his right eye and then align the
corneal reflection with the white line on the
top of the tube by closing your right eye.
 Repeat similarly for the left eye of the subject,
note down the IPD and lock it for further
measurements.

11. Measurement of Simultaneous Perception
 The tubes are objectively (by the examiner) and
subjectively (by the patient) adjusted so that either
the lion is perceived to be inside the cage or one
image is suppressed.
 If the subject is unable to see the lion and the
cage at the same time, then there is a central
repulsive defect in the eye corresponding to the
image that is not seen.
 In this case, we use larger images to move away
from the area of repulsive scotoma.

12. Measurement of the objective and subjective angle of deviation
Objective - By alternatively switching off the lights illuminating the slides
an alternate cover test is performed.
 The patient’s eyes are dissociated and as the single illuminated picture
is projected onto each fovea alternately a re-fixation movement occurs.
 The direction of the eye movement is examined and the tube before the
non fixing eye is adjusted until no eye movement is seen, or reversal of
movement is noticed.
 The measurement is then read off the scale in degrees.

13. Subjective –
 The patient pulls/pushes the handle
controlling the non-fixing eye’s tube until
the two images are superimposed.
 If this is difficult or not possible
suppression may be present and a larger
target should be introduced, however, if
superimposition is not achieved with
peripheral slides then the patient has no
potential BSV.

14. Subjective –
 The patient pulls/pushes the handle
controlling the non-fixing eye’s tube until
the two images are superimposed.
 If this is difficult or not possible
suppression may be present and a larger
target should be introduced, however, if
superimposition is not achieved with
peripheral slides then the patient has no
potential BSV.

15. Retinal correspondence
 Comparison of objective and subjective squint angle
Normal retinal correspondence (NRC)
Difference between these values is greater than three degrees
Equal or the difference between these values is less than three degrees
Abnormal retinal correspondence (ARC)

17.  One tube is locked, at zero, and the patient is
instructed to move the image, as with SP, and
create a composite image of the rabbit holding
a bunch of flowers.
 It is important to question the patient about the
“controls” to prove sensory fusion or assess
for the presence of suppression.
Measurement of Sensory (SF) and Motor Fusion (MF)

18.  The range of motor fusion is then tested by locking the columns at this
corrected angle and converging/ diverging the tubes until either control
disappears or the image splits into two.
 The vergences may then be read off the scale in degrees.

19. Measurement of Stereopsis
 A gross qualitative stereopsis assessment
 The goal of the examination is for the patient to arrange the individual
elements of the picture in the correct order.
 If the image is rotated, the perception of the order of the image elements
changes.

20. Accommodative convergence to accommodation ratio (AC/A ratio)
 The gradient method is most often used, when accommodation, minus
without accommodation is divided by the change in accommodation.
 This can be assessed on the Synoptophore by adjusting the IPD to the
patient, placing foveal SP slides into the slide holders and measuring the
objective angle (Δ), then repeating with -3.00DS.
i.e. +18Δ - +9Δ / 3DS = 3:1

21. After Image test
 Slides with one vertical and one horizontal bar
 Light intensity light on one eye for 10sec, then switch it off and
illuminate the other eye for 10sec.
 Patient is asked to draw the cross as he/she perceived.

23. Presence and type of suppression
 The area of suppression may be mapped out by initially recording the angle
at which the image is suppressed, then as the tube is rotated horizontally or
vertically record when both pictures are again apparent and subtract one
from the other.
 As the rheostat controls the illumination presented to the fixing eye
lowering the illumination until simultaneous perception is achievable gives
an estimate of the density of suppression.

24. Amsler's grid
 Binocular Amsler test is used.
 Unlike the classic monocular Amsler test, which
detects damage in the range of 20°, the binocular
Amsler test for the synoptophore is reduced in size
to 10°.
 Binocular Amsler is designed to detect functional
scotoma in binocular vision.
 Useful to understand the difference between
anisometropic amblyopia and induced amblyopia
microtropia.

25. Fig. A-central scotoma in anisometropic amblyopia, B-paracentral scotoma in
right-sided microtropic amblyopia under monocular conditions
Central scotoma is almost always detected in a patient with anisometropic
amblyopia.
While a patient with microtropic amblyopia and central fixation usually reports
paracentral scotoma on the temporal side.

26. Torsion
 Maddox slides (white binding)
 The examiner rotates the torsional
control until the patient is satisfied that
it superimposes in the centre of the
green surround and all lines should run
parallel.

27. Therapeutic Uses of Synoptophore in
1. Suppression
2. Retinal correspondence
3. Correction of Eccentric Fixation (Foveal, Outer foveal, Peripheral)
4. Accomodative esotropia
5. Correction of heterophoria

28. Summary
 Synoptophore is an ophthalmic instrument, used for diagnosing
disorders of eye muscles.
 Synoptophore range of slides can provide assessment on a wide range
of binocular vision anomalies.
 All the standard measurements and treatments are possible on this
instrument including assessment of cyclophoria, hyperphoria,
horizontal vertical vergences.
 Synoptophore also has an irreplaceable place in binocular vision
therapy.

29. References
 (PDF) Technique for Measuring Strabismus with Synoptophore -Review (researchgate.net)
 https://www.slideshare.net/LoknathGoswami/synoptophore-and-its-parts