Questions and Answers
What are the causes of developmental dysconjugate disorders of the eye?
What is esotropia?
A developmental dysconjugate disorder where one eye looks straight ahead while the other eye deviates inward.
What is exotropia?
A developmental dysconjugate disorder where one eye looks straight ahead while the other eye deviates outward.
The new onset of dysconjugate gaze in adults is rarely caused by cranial nerve injuries.
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What occurs when a patient with left CN6 paralysis looks to the right?
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What are the signs of left CN3 paralysis?
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What is the maximum deviation seen in left CN4 paralysis?
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Study Notes
Developmental Dysconjugate Disorders of the Eye
- Caused by an imbalance in ocular muscle tone, often present in early childhood.
- May have hereditary origins with various causes.
- Classified as esotropia (inward deviation) or exotropia (outward deviation).
- Clinical assessment includes the cover-uncover test for diagnosis.
Esotropia
- Characterized by one eye looking straight while the other deviates inward.
- Asymmetric corneal reflections indicate the condition.
- Cover-uncover test reveals the bad eye's tendency to move to a normal position when the good eye is covered, reverting back upon uncovering.
Exotropia
- Defined by one eye looking straight ahead and the other deviating outward.
- Cover-uncover test shows the bad eye moving to a normal position when the good eye is covered, with the bad eye returning to an outward deviation upon uncovering.
Cranial Nerve Disorders and Dysconjugate Gaze in Adults
- New onset of dysconjugate gaze in adults typically results from cranial nerve injuries, lesions, or abnormalities due to conditions like trauma, multiple sclerosis, or syphilis.
- Key cranial nerves involved include CN3 (oculomotor), CN4 (trochlear), and CN6 (abducens).
Left CN6 Paralysis
- When looking to the right, the eyes move conjugately (right eye abducts, left eye adducts).
- Esotropia manifests when looking straight ahead, with the left eye adducted.
- Maximum esotropia occurs when the patient looks to the left; the left eye remains adducted.
- CN6 is responsible for the function of the lateral rectus muscle, which abducts the eye.
Left CN3 Paralysis
- Exhibits exotropia of the left eye when looking straight ahead.
- Impairs upward, downward, and inward eye movements.
- Associated symptoms include ptosis (drooping eyelid) and pupillary dilation.
- CN3 controls several eye muscles: superior rectus, inferior rectus, medial rectus, inferior oblique, constrictor pupillae, and levator palpebrae.
Left CN4 Paralysis
- The left eye cannot turn downward when turned inward, with maximal deviation in this direction.
- CN4, or trochlear nerve, innervates the superior oblique muscle responsible for intorsion (down and out movement) of the eye.
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Description
Test your knowledge on developmental dysconjugate disorders of the eye with these flashcards. Understand conditions like esotropia and exotropia, their causes, and diagnostic methods such as the cover-uncover test. Perfect for students in eye health or neurology fields.
