Suppression third yr arya
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This document discusses suppression, which is one of the three mechanisms of sensory adaptation that occurs in patients with strabismus. Suppression refers to the active inhibition of the image from the deviated eye to avoid diplopia. There are different types of suppression depending on factors such as etiology, retinal area involved, constancy, and the eye affected. Several tests are used to diagnose suppression including the Worth four dot test, Bagolini striated glass test, and visual acuity testing. Treatment involves refractive correction, occlusion therapy, eye alignment procedures, and anti-suppression exercises.
![1. Proper refractive correction
2. Occlusion therapy
3. Alignment of visual axes
4. Anti suppression orthoptic exercise
[A] Diplopia exercise
[B] exercise with use of red filter at near and
distance
[C] exercise using major ambloscope
[D] exercise with cheirscope
[E] exercise with Tibbs binocular trainer](https://image.slidesharecdn.com/suppressionthirdyrarya-200107154030/85/Suppression-third-yr-arya-17-320.jpg)
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Suppression third yr arya
- 1. SUPPRESSION
- 2. A sensory adaptation may be defined as the manner in which a patient makes sensory adjustments to an interruption in the normal binocular single vision caused by the occurrence of squint. There are three mechanism of sensory adaptation. 1. Suppression 2. Amblyopia 3. Anomalous retinal correspondence
- 3. It is defined as active central inhibition of the desperate and the confusing image originated from the deviated eye.
- 4. Depending upon the etiopathogenesis 1. Physiological suppression 2. Pathological suppression (abnormal) i) facultative ii) obligatory Depending upon the retinal area where image is suppressed. 1. Foveal suppression 2. Macular suppression 3. Peripheral suppression
- 5. Depending upon the constancy 1. Intermittent 2. Constant Depending upon the eye involved 1. Monocular 2. Alternating
- 6. It refers to suppression present in everyday life of every individual having normal binocular single vision. It occurs due to retinal rivalry and to avoid physiological diplopia. For example – while using monocular microscope ,monocular telescope.
- 7. It refers to the suppression of the image of one eye that occurs to avoid diplopia and/or confusion. It occurs in patient with strabismus and anisometropia. 1. Facultative – it occurs to avoid diplopia and/confusion under conditions of binocular vision bur ceases when the fixating or dominant eye is covered 2. Obligatory – it refers to the constant suppression of the image from one eye which occurs under all conditions and remains even when fixating or dominant eye is covered.
- 8. The extent of the area of the retina that becomes suppressed and the time period during which suppression occurs depends upon the content of the visual field . Suppression does not occur over the whole retina. It is restricted or localized to a region around fovea of the deviating eye and a peripheral region of the deviating eye on which the fixation object is imaged.
- 9. Usually the deviated eye has the regional suppression i.e. horizontal oval area including fovea and the peripheral area is suppressed. Some authors believe that patients with exodeviation have hemi retinal suppression rather than regional suppression. Suppression may occur in fixating eye.
- 10. 1. Worth four dot test 2. 4 D base out prism test 3. Diplopia test or red glass test 4. Bagolini striated glass test 5. Visual acuity test with project-O-chart slide of American optical 6. Synoptophore test 7. After image testing
- 11. -To diagnose the suppression involving the peripheral retina. -for this test red-green goggles are used. Red color in right eye and green color in left eye. -The patient having left suppression will see only two red lights and that having right suppression will see only three green lights. - In the presence of alternate suppression patient will see alternately two red lights and three green lights.
- 12. This test is performed for detection of small angle heterotropias and presence of central suppression scotoma. To perform this test patient fixates a penlight than a 4 D prism is placed with base out in front of the right eye and the examiner observes the presence of biphasic corrective movement of left eye. This is absent in presence of central suppression scotoma.
- 13. The prism displaces the image from the fovea of right eye towards a point on a temporal half of the retina. The relaxation movement of right eye will elicit conjugate movement of both eye of left side. If right eye has no Foveal suppression this displaces the image in the left eye from the fovea to temporal retina. Thus left eye will make fusional movement in opposite direction if no Foveal suppression is present.
- 14. A pair of striated glasses are used in front of each eye. A source of light is seen as a line at right angles to striations. 1. Symmetrical cross response- in absence of manifest squint ,indicates NRC and in presence of manifest squint indicates ARC 2. Single line – it indicates suppression in other eye
- 15. To measure the depth of suppression patient is asked to fixate a small light and the red ladder filter, in increasing density are placed in front of the fixating eye till patient sees double light. The greater number of layers needed the deeper is suppression.
- 16. INDICATION 1. Patients with intermittent tropias 2. Patients with convergence insufficiency 3. Person with constant tropias 4. Person with fully corrected accommodative esotropias 5. Post surgical patients with slight under correction.
- 17. 1. Proper refractive correction 2. Occlusion therapy 3. Alignment of visual axes 4. Anti suppression orthoptic exercise [A] Diplopia exercise [B] exercise with use of red filter at near and distance [C] exercise using major ambloscope [D] exercise with cheirscope [E] exercise with Tibbs binocular trainer