Synoptophore.pptx

Principle of Synoptophore
Parts of Synoptophore

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

2. Presentation layout

3. Orthoptic instrument to perform comprehensive assessment of binocular vision. Range or bearing Syn opto phore Both Introduction

4. B ased 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 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: 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. R etinal 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 )

16. 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)

17. T he 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.

18. 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.

19. 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. +18 Δ - +9Δ / 3 DS = 3:1

20. 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.

21. P resence 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 .

22. 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.

23. 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.

24. Torsion Maddox slides (white binding) T he 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.

25. Therapeutic Uses of Synoptophore in Suppression Retinal correspondence Correction of Eccentric Fixation (Foveal, Outer foveal, Peripheral ) Accomodative esotropia 5. Correction of heterophoria

26. 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.

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