antisuppression exercises.ppt
- 1. Antisuppression Exercises Mahendra Singh Assistant Professor and consultant Optometrist. CL Gupta Eye Institute. UP India
- 2. What is Suppression?? • Suppression is active but unconscious and involuntary inhibition of vision in one eye • Present under conditions of binocular viewing • Occurs as diplopia occurs
- 3. Antisuppression Therapy • Anyone who has undergone therapy for ARC or Amblyopia has already had some therapy for suppression • This involves using first degree fusion targets • Once patient can superimpose targets with NRC, Antisuppression therapy can begin
- 4. Indications • Amblyopia • Suppression • Ocular deviations • ARC- Abnormal Retinal Correspondence
- 5. Goals of Suppression Treatment • Make patient aware of diplopia • This diplopia needs to be appreciated with one eye deviating • Make patient hold fixation with either eye always seeing the blurred image
- 6. Contd.. • Establish sensory fusion and proper retinal correspondence • Then stabilize sensory fusion • Then improve motor fusion
- 7. Treatment of Suppression • Treat if any strabismus • Proper refractive error correction • Allignment of visual axis- to permit simultaneous stimulation of corressponding retinal element by same object
- 8. Contd.. • Occlusion therapy in case to overcome amblyopia • Antisuppression orthoptic exercise before or after surgical therapy of strabismus
- 9. When breaking down Suppression consider the following • Brightness • Target Size • Intermittent Stimuli • Target Movement • Target Contrast • Color • Tactile and Kinesthetic Senses • Auditory Sense
- 10. Brightness • Brighter target easy for suppressing eye to see • Always put brighter target in front of suppressing eye • Deeper suppression larger difference in brightness of the two targets
- 11. Target Size • Targets used in antisuppression training should be larger than suppression scotoma • Target becomes smaller with therapy as the scotoma shrinks • Progress slows once foveal antisuppression begins because this is most difficult to eliminate
- 12. Intermittent Photic Stimuli • Flashing stimuli to suppressing eye • Flashing amblyoscope target works well
- 13. Target Movement • By moving the target non corressponding points are stimulated and these are less likely to be suppressed • Also by moving the target you keep the patients attention making suppression of image less likely
- 14. Target Contrast • More contrast between background and foreground in target less likely target will be suppressed • Thus suppression is difficult to break under natural conditions because the contrast is low
- 15. Color • Color targets need to be used because • More interesting to patients • And are more difficult to suppress than black and white targets
- 16. Auditory Sense • Some devices such as Eye Hand coordinator use buzzers through which he/she can be aware if doing the exercises incorrectly • Sound provides immediate feedback • Motivates the patient and improvement occurs as the suppression is broken
- 17. Antisuppression Therapies • Cheiroscope • Tube and Hand • Brock String • Chiastopic Training • Bar Reader • Vectograms • Tranaglyphs • Brewster Stereoscope • Modified Brock Posture Board
- 18. Brock String And Beads • This is an outstanding therapy because of diplopia awareness and fixation accuracy • Brock String is inexpensive and an easy home therapy • Teaches patient how to aim eyes together correctly for varying distances • It allows the patient to determine if she/he is shutting of an eye or suppressing • This is usually first technique patient is taught and is often given as home therapy
- 20. Procedure • Place one end of string on tip of your nose • Nearest bead app 10 inches away middle bead 20 inch and farthest bead 30 inch away • Look at middle bead, you can be aware 2strings farther and 2strings closer and the farthest and nearest bead appeared double • Similarly keep looking at the farthest bead and also at nearest bead • Wear any special lenses and prisms that were prescribed and they may change as therapy progresses
- 21. “Tube and Hand” • Also known as “Hole in Hand” • Simple and effective antisuppression therapy option for preschoolers • Patient holds cardboard tube before one eye and holds his hand in front of other eye • Patient should see both the circle and the hand simultaneously • If doesn’t means he/she is suppressing one eye so need to teach him
- 22. Cheiroscope • Cheiroscope is drawing exercise and should not be used on patient with ARC because it will reinforce it • It is used to assess binocular stability and to detect the presence and extent of suppression • Training on it gives patient important feedback that he is suppressing the eye and gives him an opportunity to gain binocular control necessary to eliminate his suppression
- 23. Cheiroscope
- 24. Procedure • Dominant eye fixates a simple picture through a mirror • Non Dominant eye views a blank piece of paper, onto which the patient copies the picture seen by the other eye • Examiner must watch the patient to make sure he/she does not alternately fixate which can be monitored by using a mirror that also changes the picture's size • If the drawn picture is the same size as the original, the patient is alternately fixating
- 25. Bar Reader • The Bar Reader, or reading with a physical anaglyphic or polarized septum between the patient and the material • It must be used for those with no strabismus because alignment is necessary for the patient to read
- 26. Chiastopic Training • It is done by voluntarily crossing (i.e., converging) the eyes to fuse two objects held out in front of the patient • The targets can be pencils, fingers/thumbs, eccentric circles, or any other paired items • It is a difficult skill that may discourage the patient • Do not use this technique early in therapy
- 28. Vectogram • Vectograms with 'suppression checks' and various sizes of targets are an excellent option for therapy • The patient wears polarized lenses over any prescription glasses • Parts of the pictures are missing if the patient suppresses
- 30. Tranaglyphs • Tranaglyphs, or targets used with red-green glasses, are similar to vectograms • They come in different sizes and in various amount of detail with suppression cues
- 31. Procedure • Is done with a slide of alternating red and green bars that is placed over reading material or over the TV screen • While the patient wears red-green glasses • Two full- or half-size sheets of red acetate and green acetate can also be placed over the TV (or computer) screen • This method is also known as a "TV trainer" and works great with video games • If the patient suppresses, the whole picture is not seen.
- 32. Contd.. • Other Tranaglyphic techniques can be created using the same principles • Another example of an anaglyphic anti- suppression technique is Sherman's palying cards, available from Bernell • With these playing cards and red and green glasses, the patient must be using both eyes to see all of the cards
- 35. Stereoscope • Stereoscope uses stereograms as targets for superimposition • The patient needs to see both targets, the dog and pig with the Telebinocular • This can train at distance and near
- 36. Modified Brock Posture Board • It uses red-green spectacles, sheets of white paper and red translucent plastic of identical size, a penlight and red marker • The patient draws lines on the white paper with the red marker • The paper is held beneath the red sheet with one hand while the other holds the penlight
- 37. Contd.. • The patient then traces the lines with the penlight and sees the red lines on white paper with the left eye • Only the right eye sees the penlight tracing the lines (seen by the left eye) below the paper
- 38. Amblyoscope • The amblyoscope is a machine which trains a child to use his/her eyes together • The goal is to achieve binocular fusion, or normal two-eyed, single vision with depth perception • As the child progresses in skill therapist increases the fusional demands to stretch and normalize the patient's ability to efficiently use his/her two eyes together
- 39. Contd.. • This machine also allows a child to know when he/she is suppressing an eye • Visual awareness is the first step in successful training
- 40. Various Exercises on Amblyoscope • Autoflash • Kinetic Stimulation • Macular Massaging • Chasing Technique
- 41. “Flippers” • Lenses and prisms are always important in visual training • Here a child is working on a focusing technique called accommodative rock • The "flippers" hold two different sets of lenses • One is a pair of plus lenses; the other are minus
- 42. Contd.. • By rapidly alternating between the two sets of lenses, the patient is forced to relax or stimulate accommodation in order to clearly see the print thus gaining greater facility and control over his focusing • Patients always begin with lower powered lenses and gradually increase the strength at which they can successfully complete the task
- 43. Push Up Test • Eyes with conditions called Convergence Insufficiency and Exotropia have difficulty turning their eyes inward • As a result, they often struggle because they simply can't maintain the inward eye aim required most close up activities • These children have to be taught to converge their eyes
- 44. Contd.. • Here a therapist is helping a young patient experience the "tug" she should feel on both sides of her nose bridge as muscles located there contract and pull her eyes inward • Kinesthetic awareness is an important first step in teaching the child to control her eye coordination
- 45. Saccadic Fixator • The saccadic fixator is an instrument which trains saccadic eye movements, tracking, visual memory, peripheral awareness, and visual motor integration • It allows the children to set goals for themselves as they continually strive to improve their last performance
- 46. Contd.. • Besides children with oculomotor dysfunctions, this machine is particularly good for young athletes; it improves their eye-hand- body coordination and response time • Overall, it's an excellent trainer for visual stamina and efficiency
- 47. Rotator • The rotator is an instrument used to increase a child's visual efficiency and stamina • Used primarily to improve eye movements the child is asked to place golf tees in a rotating pegboard • As the child's skill improves, the speed at which the pegboard is rotating is gradually increased
- 48. Contd.. • This procedure is usually done while the patient is wearing a patch over one eye • Strong monocular ("one-eyed") skills must be gained before a child can achieve good binocular, two- eyed skills