Presentation on theme: "M. SOLTAN SANJARI, M.D. RASSOUL AKRAM HOSPITAL I. U. M. S."— Presentation transcript:
1M. SOLTAN SANJARI, M.D. RASSOUL AKRAM HOSPITAL I. U. M. S. NYSTAGMUSM. SOLTAN SANJARI, M.D.RASSOUL AKRAM HOSPITALI. U. M. S.
2NYSTAGMUSNystagmus is a rhythmic oscilation of one or both eyes about one or more axes.
3NYSTAGMUS Ethiology 1. Secondary to visual deficit 2. Secondary to intracraniallesions and drug toxicit3. Congenital benign idiopathic
4NYSTAGMUS Mechanisms: 1. The nystagmus intensity is too high, or vision is too poor for complete suppression2. Concomitant disorder of the smooth pursuit system3. The fixation and smooth pursuit systems are themselves at fault
5NYSTAGMUS Classification: 1. Clinical appearance 2. The waveform as revealed by ENG3. Etiological grounds
6NYSTAGMUS Terminology: Congenital Jerk and Pendular Nystagmus 1.Sensory Defect Nystagmus (SDN)2. Congenital Idiopathic Nystagmus (CIN)Jerk and Pendular NystagmusAxes of OscillationsDirectionNull ZoneAmplitude, Frequency, Intensity
16NYSTAGMUS Latent Nystagmus (LN): Most common Before 6 mo. Horizontal, Jerk, ConjugateWave formPrimary position, Add., Abd. Head turnGenetic factor
17MLN plus Alternating fixation strabismus fast phases always in the direction of the fixating eyemisdiagnosed as having CN, because the nystagmus is present with both eye opens
18NYSTAGMUS SDN, and CIN: Sensory Defect ? Incidence 9/1 Horizontal, Circumrotatory in early infancyNull Zone ( 1/3 is eccentric )IntensityInheritanceOptokinetic ResponseWave formVisual PerformanceOscillopsia
19Congenital nystagmusCharacteristics: Binocular Similar amplitude in both eyes Usually uniplanar (horizontal) in all gazes Diminished by convergence Increased by fixation attempt Superimposition of latent component Abolished in sleep Head oscillations
23Sensory Defect Nystagmus Consequent to bilateral visual losscannot be distinguished from CIN in a patient with coexisting primary visual abnormalities.Monocular visual loss may produce monocular nystagmus, usually vertical, at any age from birth through adult life (it may mimic spasmus nutans, particularly if there is associated head nodding)
24NEUROLOGICAL AND NEUROMUSCULAR NYSTAGMUS Gaze Paretic NystagmusThe most common form of N. after infancyMismatch between gaze-holding circuit and EOM dynamicsHead thrustsCerebellar Disease, Drugs, Myasthenia, Vestibular Disease, …………….
34NEUROLOGICAL AND NEUROMUSCULAR NYSTAGMUS See-saw NystagmusElevates and IntortsDepresses and ExtortsBitemporal hemianopia (Maddox 1914)Parasellar and Chiasmal LesionsDamage to the pathway of zonaincerta to the interstitial nucleus of Cajal (Thalamic lesion)Congenital and Idiopathic
47NEUROLOGICAL AND NEUROMUSCULAR NYSTAGMUS Torsional NystagmusSometimes only detect by ophthalmoscopyMidpontine , Central vestibular connections LesionsPart of SSN, Peripheral vestibular Nystagmus, SDN/CIN, LN.
49NEUROLOGICAL AND NEUROMUSCULAR NYSTAGMUS Abduction NystagmusINO, Myasthenia, After strabismus surgeryPeriodic Alternating NystagmusAcquired. Part of SDN/CIN90 Second each cyclePing-Pong GazeLower brain stem, Cerebellar, AnomaliesDrugs, Chronic alcoholism.Baclofen Sometimes useful
50NEUROLOGICAL AND NEUROMUSCULAR NYSTAGMUS Epileptic NystagmusRare but may be the only sign of seizureUsually HorizontalLid NystagmusUsually associated with vertical nystagmusIcthal phenomenon, Posterior fossa lesions,
60Surgical Treatment To eliminate a compensatory head posture To decrease nystagmus amplitude, or for both reasonsstrabismus surgery may convert manifest-latent nystagmus to latent nystagmus, causing improvement of binocular visual acuity
61Head Turn“the eyes should always be shifted in the direction of the anomalous head posture”Head turn or tilt of more than 15 to 20 is of cosmetic or functional significanceAscertain beyond doubt by repeated examinations that the direction of the null zone and thus of the head turn is consistent
62Head Turn Kestenbaum-Anderson Procedure Posterior Fixation Suture Modified Anderson ProcedureModification for coexisting heterotropia
63Chin-Up or Down Large recession of vertical muscles Think about lids positionVertical R & R
64Head Tilt Horizontal or vertical muscles displacement For head tilt to right:Transposing right SR nasally and right IR temporally and opposite in left eyeorSupraplacement of right LR and infraplacementof right MR
65To decrease nystagmus amplitude Large recession of 4 horizontal musclesDisinsertion and reinsertion of 4 horizontal muscles (Hertel)