Questions and Answers
What condition is caused by a difference in refractive error between the eyes?
Which treatment method for amblyopia involves patching the better-seeing eye?
What type of amblyopia results primarily from uncorrected astigmatism?
What is the maximum age by which amblyopia treatment should preferably be completed?
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What should be done to prevent amblyopia in preschool children?
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What does strabismus refer to?
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What is the primary characteristic of fully refractive accommodative esotropia?
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What role do bifocal glasses play in the treatment of non-refractive accommodative esotropia?
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What is a significant cause of non-refractive accommodative esotropia?
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What distinguishes partially refractive accommodative esotropia from fully refractive accommodative esotropia?
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Which type of condition can lead to sensory exotropia?
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When is a fundus examination essential in children with strabismus?
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Which of the following accurately describes concomitant exotropia?
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What is a common characteristic of amblyopia when associated with partially refractive accommodative esotropia?
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What characterizes distance exotropia?
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At what age does intermittent exotropia typically start presenting?
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What is a common cause of consecutive exotropia?
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Which type of exotropia is characterized by a large and stable angle developing within the first 6 months of life?
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How does the treatment for poorly controlled or deteriorated intermittent exotropia typically proceed?
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What distinguishes oculomotor nerve (CNIII) palsy related to pupil involvement?
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Which statement correctly identifies the nature of apparent exotropia?
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What is a potential complication of surgical lesions related to the oculomotor nerve?
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What is a common characteristic of double vision in patients with abducent nerve palsy?
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In the case of unilateral abducent nerve palsy, which compensatory behavior is commonly observed?
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What factor in a patient's history is important for diagnosing strabismus?
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What is typically evaluated during a general examination for strabismus?
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Which aspect of visual function is crucial in determining strabismus management in adults?
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What type of strabismus suggests a risk of amblyopia in children?
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What type of deviation is most likely associated with unilateral abducent nerve palsy?
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Which examination is mandatory to identify any underlying pathology in strabismus evaluation?
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What is a common clinical feature of oculomotor nerve palsy?
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Which treatment option is typically considered first in presumed microvascular cases of oculomotor nerve palsy?
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In trochlear nerve palsy, which head posture is commonly observed?
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During the Parks three-step test, what is assessed in step two?
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Which symptom indicates a surgical cause of oculomotor nerve palsy?
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What is the main ocular movement limitation seen in trochlear nerve palsy?
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What diagnostic investigation is often required for suspected surgical causes of oculomotor nerve palsy?
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Which of the following is a characteristic of normal ocular movements that remains intact in oculomotor nerve palsy?
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Study Notes
Amblyopia Types
- Anisometropic Amblyopia: Caused by a refractive error difference between the eyes, potentially as small as 1 dioptre.
- Bilateral Ametropic Amblyopia: Results from high symmetrical refractive errors, commonly hypermetropia.
- Meridional Amblyopia: Caused by uncorrected astigmatism (usually >1 D) leading to image blur in one meridian; can be unilateral or bilateral.
Amblyopia Management
- Prevention: Implement screening programs for preschool children to identify amblyopia. Correct underlying refractive errors with full-time spectacles.
- Treatment Timing: Necessary before age 8-9, during the sensitive period of visual development.
- Occlusion Therapy: Patching of the better-seeing eye to stimulate the amblyopic eye; requires careful monitoring to prevent amblyopia in the patched eye.
- Atropine Penalization: Use of 1% atropine drops to blur vision in the stronger eye (aiming for approximately 6/18 vision).
Strabismus Overview
- Definition: Misalignment of visual axes, preventing binocular single vision (BSV).
- Refractive Accommodative Esotropia: Esotropia is observed when hypermetropia is uncorrected; correction restores BSV.
- Non-Refractive Accommodative Esotropia: Related to the interaction of accommodation and convergence, often associated with an abnormal AC/A ratio.
- Treatment: Bifocal prescriptions can help maintain ocular alignment at near distances.
Types of Esotropia
- Fully Refractive Accommodative Esotropia: Reversed upon correcting hypermetropia.
- Partially Refractive Accommodative Esotropia: Deviation reduced but not eliminated with correction; often requires surgical intervention for residual squint.
Exotropia Categories
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Intermittent Exotropia: Occurs with visual inattention or fatigue, commonly beginning at two years of age.
- Distance vs Near: Classification includes distance exotropia, near exotropia, and basic exotropia based on the angle of deviation.
- Congenital Exotropia: Present at birth without significant refractive error; typically has a stable and large deviation.
Incomitant Strabismus
- Oculomotor Nerve (CNIII) Palsy: Resulting symptoms include ptosis, limited ocular movement, and a dilated pupil if the cause is surgical. Requires imaging if a surgical cause is suspected.
- Trochlear Nerve (CNIV) Palsy: Characterized by hypertropia worsened in opposite gaze; compensatory head tilting often occurs.
- Abducent Nerve (CNVI) Palsy: Double vision is worse for distant targets; abduction is limited, causing esotropia.
Evaluation of Strabismus
- Clinical History: Duration, variability, laterality, and previous treatments for effective diagnosis and management.
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General Examination:
- Observation of head posture and facial/ocular anomalies.
- Check visual acuity and refraction to address ametropic influences.
- Fundus examination is essential to rule out underlying pathology.
- Extraocular Movements: Assessment to identify incomitant squints and measurement of deviation.
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Description
This quiz covers the different types of amblyopia, including anisometropic, bilateral ametropic, and meridional amblyopia. It highlights the causes linked to refractive errors and discusses management and prevention strategies. Test your knowledge on this important visual condition!
