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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 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 http://www.takagij.com/seihin_e/katarogu_e/mt364_e.html