Presentation on theme: "Approach to a patient with diplopia"— Presentation transcript:
1 Approach to a patient with diplopia Dr. R.R.BattuNarayana Nethralaya
2 What does the faculty of BSV require? Perfect ( or near perfect ) alignment of the visual axes simultaneously on the object of regardPerfect ( or near perfect ) retinal correspondencePerfect central ( or paracentral ) fusional capability.Perfect ( or near perfect ) alignment of the retinal receptorsPerfect ( or near perfect ) optics to allow only one image to be formed on the retina and the same single image to be formed on the other
3 What is Diplopia ?It is when more than one image ( two ) of the object of regard are seen simultaneouslyThis occurs when….(Mechanisms)More than one image of the object of regard is formed in the retinae of one or both eyes ( monocular diplopia)The eyes lose their simultaneous alignment with the object of regard in one or more directions ( or distances ) of gaze (incomitance of ocular alignment – binocular diplopia)The eyes although aligned, send images to the brain which disallow fusion ( aniseikonia )Local retinocerebral adaptations to misalignments in early life go askew (paradoxical diplopia, loss of suppression)Rarely, purely cerebral mechanisms
4 Monocular vs Binocular Diplopia Key questionIs the double vision present even on monocular eye closure?
5 Monocular diplopiaMore than one image of the object of regard is formed in the retinae of one or both eyes…..Irregular astigmatism ( nebular scars, haze, corneal distortion)Subluxated clear lensesPoorly fitting contact lensesEarly cataractIridodialysis, polycoria, large iridotomiesMacular disorders – edema, CNVM etc
6 Binocular DiplopiaThe eyes lose their simultaneous alignment with the object of regard in one or more directions ( or distances ) of gaze (incomitance of ocular alignment – binocular diplopia)Key cluesAnomalous Head PositionVision Blurry in one gaze position, better in anotherVestibular signsLong tract signsObviously misaligned eyes, proptosisPresence of partial ptosisNystagmus
7 Questions to be asked Is there a mis alignment? If so, in which directions ( or distances ) of gaze?Which are the hypofunctioning ( and hyperfunctioning ) muscles?Do they have a neurogenic pattern, or a restrictive pattern or a neuromuscular pattern or a myogenic pattern?
9 Diplopia - Key questions Is the diplopia more for distance or near? Is the diplopia predominantly horizontal or vertical?In which direction of gaze are the images maximally separated?To which eye does the “outer” image belong?Is there a predominant tilt?In which position of gaze does the tilt increase maximally?
10 Diplopia chartingDiplopia is maximum ( separation of images) in the field of action of the paralysed muscle.The false image ( the image belonging to the eye with the hypofunctioning muscle ) is always peripherally situatedHigher in upgaze, lower in downgaze, on the right in right gaze and on the left in left gaze
11 Hess Charting Based on the principle of confusion Allows for identifying the position of one eye, while the other eye fixes in different positions of gaze.Effectively demonstrates Sherrington’s and Hering’s lawsAllows for more objective follow up also.
12 The cover-uncover and alternate cover tests Probably the most important objective tests to evaluate muscle palsiesMeasurements with a prism bar allow for measurementMeasure in the 9 cardinal gaze positionsDistance and near
13 Versions & Ductions Allow to assess actual rotation limits Allow assessment of underactions and overactions of synergists
14 Saccadic Velocity“Floating saccades” are suggestive of a nerve palsy or paresisIndirectly “oblique saccade” testing can be done.Normal saccadic velocity with limitation indicates a restricted muscle
15 Forced Duction Testing Allows to assess forced movement in direction of restrictionImportant in Blow out fractures, TED, long standing strabismus with contracturesImportant to lift the globe and rotate
16 Force Generation Testing Allows to identify residual power in a suspected paretic muscle. Usually done to direct management6th N palsyRecess – resect or muscle transposition
17 Pointers to primary orbital disease Restrictive muscle hypofunctionProptosisSigns of orbital inflammationSigns of anterior segment, lid and adnexal hyperemia or inflammation
18 Neurological diseaseLook for supranuclear, nuclear and infranuclear patternsLook for sensory ( visual ) abnormalitiesLook for nystagmusLook for vestibular – auditory symptomsLook for other cranial nerve involvementLook for long tract signs
19 CNS and orbital imaging Done for obvious neurological patternsOrbital inflammatory disease, proptosisOccasionally may avoid or delayPupil sparing 3rd in a diabetic6th Nerve in a hypertensive, image if no spontaneous recovery in a few weeks
20 ImagingCTMRIFat suppressionStir sequencesMRA vs CT angio
21 Ancillary tests Tests for myasthenia Tests of thyroid function X- ray chestBloods
22 Aniseikonia Occurs when image size disparity exceeds 5% Previously seen in monocular aphakiaMay occur following keratorefractive surgery
23 Convergence insufficiency Classically for nearCould be primary or secondary