Evaluation of squint rakhi (2)
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The document discusses the evaluation of strabismus. It defines strabismus and the different types such as phoria, tropia, comitant, and incomitant. It describes the history to obtain and various tests used in the examination including motor function tests like cover test, versions, and ductions, and sensory tests like Worth 4-dot and Bagolini lenses. The document provides details on the order and components of a complete ocular examination for strabismus.
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Evaluation of squint rakhi (2)
- 1. Dr Rakhi Dcruz LVPEI,MTC,Bhubaneswar EVALUATION OF STRABISMUS 23/10/19
- 2. Strabimus –Greek word ‘Strabismos’ means to squint,to look obliquely= ocular misalignment Phoria : a latent deviation that is controlled by fusional mechanisms,so that eyes remain aligned during binocular movements Tropia : a manifest deviation that exceeds the control of fusional mechanisms -constant -intermittent Pediatric ophthalmology&strabismus-BCSC-AAO
- 3. HISTORYOcular deviation Onset: Congenital orAcquired - precipitating event Duration Constant or intermittent Diurnal variation
- 4. Past History Medical history Antenatal, Birth and Developmental history (in congenital strabismus) • Maternal illness, medication, fever with rash during pregnancy Developmental milestones (motor and intellectual – schooling) Old Photos
- 6. TERMINOLOGY 1) Comitant : size of deviation doesn’t vary by more than few prism diopters in different positions of gaze or with either eye used for fixating. 2) Incomitant : the size of deviation varies with the eye used for fixing 3) Primary deviation : deviation measured when the non paretic or non-restricted eye is fixing 4) Secondary deviation : deviation measured when paretic or restricted eye is fixing Handbook of pediatric strabismus & amblyopia-Kenneth wright,speigel,thompson
- 7. PSEUDOSTRABISMUS Pseudoesotropia • Due to flat nasal bridge • Prominent epicanthal folds • Narrow interpupillary distance • euryblepharon Pseudoexotropia • Wide interpupillary distance • Positive angle kappa with or without other ocular abnormalities Strabismus simplified-Pradeep sharma
- 8. ORDER OF EXAMINATION 1) Inspection : 2) Visual acuity 3) Sensory tests 4) Motor function tests 5) Cycloplegic refraction 6) Fundus examination
- 9. Motor evaluation tests • EOM-ductions & versions • HBT • Cover test • Cover-uncover test • Alternate cover test • MKT • PBCT Sensory evaluation tests • Worth 4 dot • Bagolini • 4 prism test
- 10. OCULAR EXAMINATION Head posture: Best time when patient is reading vision chart Face turn, head tilt, chin up, chin down Thumb rules Head tilt : Oblique muscle Chin elevation :Vertical rectus muscle Face turn : Horizontal muscle
- 11. CHIN DOWNHEADTILT &CHIN UP
- 12. FACETURN
- 13. HIRSCHBERGTEST Compares the position of corneal light reflection in both eyes, based on purkinje image 1 Degree of decentration of corneal light reflection 1 mm of decentration = 70 = 15 PD Light reflex @ pupillary margin = 30 PD Light reflex @ mid iris = 60 PD Light reflex @ limbus = 90 PD Handbook of pediatric strabismus & amblyopia-Kenneth wright,speigel,thompson
- 17. KRIMSKYSTEST Adds prism to Hirschberg test to measure strabismus Krimsky’sTest Reflections produced on both corneas with penlight The prism is placed in front of deviating eye Moves the light reflex to the centre of pupil with out a version shift Modified Krimsky’s test Prism is placed in front of focussing eye Causes version movement in which both eyes move in the direction of the apex of the prism
- 19. COVERTEST Pre requisites 1.Ability to maintain constant fixation on accommodative target 2.Foveal fixation in both eyes 3.Extra ocular muscles should be free 4.co-operative patient
- 20. COVERTEST Uses Differentiates true strabismus from pseudostrabismus Deviation is latent or manifest Fixation preference Gross idea about visual acuity Fixation targets Distance : 1 line above the BCVA Near : Accomadation target with discernable contours
- 21. COVERTEST Tropias are detected with out dissociating an existing phoria Cover the fixing eye just for 1-2 secs, not long enough which will cause break up fusion and will manifest a phoria Cover one eye and check for movement of other eye Other eye moves outwards …. Esotropia Other eye moves downwards …hypertropia Pediatric ophthalmology&strabismus-BCSC-AAO
- 22. UNCOVER TEST To check for phorias Cover the eye for few seconds and then uncover If the eye is deviated under cover a refixation movement is seen Eye on uncovering abducts--- esophoria Adducts …exophoria Downwards—Hyperphoria
- 23. ALTERNATE COVERTEST In this test binocular fusion is dissociated there by which full deviation can be measured To determine full deviation including both phoria and tropia One eye should always be occluded
- 25. PRISM ALTERNATE COVERTEST Done after alternate cover test which will give a estimate of size of deviation Alternate cover test is done by placing prism in appropriate position to neutralize deviation Determines the amount of prism to neutralize deviation . Progressively increase strength of prism till no movement on alternate cover test Handbook of pediatric strabismus & amblyopia-Kenneth wright,speigel,thompson
- 27. 4PD BASE OUTTEST In normal subjects 4 base out test induces fusional convergence Initial version movement of both eyes in the direction of apex of prism Fusional vergence movement of eye with out prism towards nose Patients with out motor fusion and large regional suppression shows no movement of either eyes when prism is placed over non- dominant eye Version movement of both eyes when its placed over fixing eye Handbook of pediatric strabismus & amblyopia-Kenneth wright,speigel,thompson
- 30. SENSORYTESTS 1) Includes diplopia tests and haploscopic tests 2) In diplopia tests one stationary target is viewed by both eyes 3) In haploscopic tests have two fixation targets for each eye and targets can be moves separately
- 31. DIPLOPIATESTS Tests that disrupt fusion are referred to as dissociating tests Includes 1) Maddox rod test 2) Worth 4-dot test 3) Bagolini striated lenses
- 32. MADDOX ROD 1) Consists of series of fused cylindrical red glass rods 2) Converts white spot of light into red streak 3) To test horizontal deviations Maddox rod is placed in such a way the cylinders are positioned horizontally 4) If the light superimposes on the line it indicates orthophoria 5) If the light is to the left of the line it indicates esodeviation
- 34. WORTH 4 DOTTEST Dissociation test For near and distance Differentites between BSV,ARC and suppression Results interpreted in presence or absence of manifest squint at the time of testing
- 36. WORTH 4-DOTTEST Patient wears red and green glasses Views a box of 4 lights- 1 red, 2 green and 1 white Results BSV– All 4 are seen 2 red– Right suppression 3 green– left suppression 2 red and 3 green– Diplopia Green and red alternate – Alternating suppression Handbook of pediatric strabismus & amblyopia-Kenneth wright,speigel,thompson
- 37. BAGOLINI LENSES These are clear lenses with a liner scratch through the centre of lens that provides a streak of light on retina while viewing a bright light Oreinted obliquely at 450 and 1350 and are not dissociating
- 39. if the two streaks form a oblique cross then the patient has BSV or harmoniousARC If two lines are seen but they don’t form a cross it indicates diplopia If only one streak is seen it indicates suppression Small gap in one of the streaks it indicates central supressin scotoma
- 40. OCULAR EXAMINATION Posterior Segment Bruckner'sTest FundusTorsion Eccentric Fixation (Foveal, Parafoveal, Perifoveal)
- 41. In intorsion : fovea is above the lower half of the disc In extorsion : fovea is below the lower half of the disc
- 42. OCULAR EXAMINATION Extraocular Movement Ductions Versions Look for superior oblique and inferior oblique over action: grading Convergence/divergence Forced DuctionTest, ForcedGenerationTest
- 44. Forced duction test : Indicated -- evidence of restricted duction For rectus muscles grasp the at limbus and rotate the eye in the field of limited ductions In right abduction limitation ask the patient to look right to relax tight medial rectus muscle Forced generation test Assesses rectus muscle strength Patient is asked to look into the field of limitation while the eyes are held in primary position
Hinweis der Redaktion
- Flase app of strabismus even when the visual axois are actually aligned
- PURKINJE IMAGE 1 IS A VIRTUAL IMAGE LOCATED BEHIND PUPIL Torchlight infront of exaineers eye– directed towrdss patient eye—so ony near target n/l– slightly decentered naally,but symmetrically located around 5 degree Alternative in uncop,poor eccentric fixn,in whom cover tets is not based on correln bwn corenal light reflx & ocular devn
- TO MEASURE DEVN IN PTS UNCOP,POOR SENSORY,POOR VN 20/400 OR WORSE prisms are inc /dec until reflx from each eye becomes equally & symmetrically centered in pupil
- Prism is placed before one eye,oriented approp, in an attaemot to neutraiz edevn,then altr cover test carried If there is residual refixation shift with prism in place then prism changed (either increased or decreased to neutralize devn be sure to keep one eye covered to maintain binocular dissoscn never sack prism in saem orient, it will lead to underestimation of angle size
- Two prisms shouldn’t be stacked in horizontal or vertical positions A horizontal or vertical prisms can be stacked together For neutralizing a deviation prism is oriented such that the apex is in the direction of deviation Prism can be placed in either eye to neutralize a deviation if its comitant
- DIAGRAM-KANSKI