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13 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Define: Incomitant deviation
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A turn in which the degree of deviation varies in different positions of gaze.
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What are 2 causes of incomitant deviations?
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1. Paralytic: muscle innervation problem. Result is total OR partial strabismus.
2. Non-paralytic: restrictive or mechanical cause of strabismus. |
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(T/F) Paretic refers to a complete weakness.
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F - Paretic is a partial weakness. Paralysis is a complete weakness.
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What is a paralytic cause of esotropia?
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CN VI (Abducens) Paresis - CN VI innervates lateral rectus muscle. Paresis will inhibit LR muscle from functioning and eye will not ABduct.
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What are some signs of a CN VI paresis?
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- incomitant esotropia (laterally and distance incomitant)
- head posture - unilateral OR bilateral - maybe a V pattern |
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What would be the indication of Moebius Syndrome?
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* caused by CN VI abducens and CN VII facial nerve paralyses *
- bilateral horizontal gaze paresis - inability to ABduct - incomplete lid closure - no facial expression, unable to smile - tongue palsy |
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What are 3 non-paralytic causes of an incomitant esodeviation?
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1. special forms
2. mechanical (restrictive) 3. orbital myositis 4. myasthenia gravis |
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Lack of development of the 6th nerve and partial innervation of the lateral rectus muscle is referred to as?
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Special forms - Duane's Retraction Syndrome (result is limitation on ABduction)
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Mechanical (restrictive) esodeviations are _________ and caused by ________ _________ muscle restriction.
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incomitant
medial rectus |
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What is orbital myositis?
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Orbital inflammation or group of orbital pseudotumors causes acute, unilateral orbital pain - increases with eye movement.
- LR myositis: limited ABduction - incomitant deviation |
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Sensory and Consecutive esotropias are examples of what?
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Secondary esodeviations
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primary or secondary
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What is the main idea behind a sensory esotropia?
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caused by decreased visual acuity in one eye (by many different means, ex. cataract, corneal scar, optic nerve anomalies, retinal detachment etc). Loss of fusion occurs, therefore no complaints of diplopia.
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What is the main idea behind a consecutive esodeviation?
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patient previously had an exodeviation which was treated but overcorrected and the result is an esodeviation.
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