Podcast
Questions and Answers
What should be considered when prescribing prism for a patient with recent-onset paresis?
What should be considered when prescribing prism for a patient with recent-onset paresis?
What condition must be present for a patient to receive corrective prisms for resolvable strabismus?
What condition must be present for a patient to receive corrective prisms for resolvable strabismus?
When monitoring a patient who has received prism therapy, how often should follow-up occur during the first month?
When monitoring a patient who has received prism therapy, how often should follow-up occur during the first month?
In patients with amblyopia, what approach should be taken concerning corrective prisms?
In patients with amblyopia, what approach should be taken concerning corrective prisms?
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What is a temporary solution suggested for patients undergoing prism adaptation?
What is a temporary solution suggested for patients undergoing prism adaptation?
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What is the effect of giving an inverse prism over a strabismic eye in patients with a poor prognosis for functional cure?
What is the effect of giving an inverse prism over a strabismic eye in patients with a poor prognosis for functional cure?
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What should not be considered when administering corrective prisms to a patient with specific conditions?
What should not be considered when administering corrective prisms to a patient with specific conditions?
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What outcome can occur with the removal of prism in patients experiencing a suppression zone?
What outcome can occur with the removal of prism in patients experiencing a suppression zone?
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What is the primary goal when using prism for patients with recent onset and short duration strabismus?
What is the primary goal when using prism for patients with recent onset and short duration strabismus?
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Which of the following criteria is used for determining the percentage of prism based on total deviation in dissociated prism criteria?
Which of the following criteria is used for determining the percentage of prism based on total deviation in dissociated prism criteria?
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What is the minimum requirement for Sheard's Criterion to achieve comfort for basic exophoria?
What is the minimum requirement for Sheard's Criterion to achieve comfort for basic exophoria?
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What is the technique recommended for moving the flattest part of fixation disparity curves to the Y-Axis?
What is the technique recommended for moving the flattest part of fixation disparity curves to the Y-Axis?
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What is the primary purpose of fusion prisms when treating strabismus?
What is the primary purpose of fusion prisms when treating strabismus?
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With respect to prism recommendations for longstanding strabismus, what should be assessed?
With respect to prism recommendations for longstanding strabismus, what should be assessed?
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How much prism is ideally prescribed for intermittent strabismus based on the associated criteria?
How much prism is ideally prescribed for intermittent strabismus based on the associated criteria?
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What initial approach should be taken for patients with constant strabismus who can achieve binocular vision with prism?
What initial approach should be taken for patients with constant strabismus who can achieve binocular vision with prism?
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Which type of amblyopia is typically considered more favorable for treatment outcomes?
Which type of amblyopia is typically considered more favorable for treatment outcomes?
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What is the primary goal of corrective (neutralizing) prism therapy?
What is the primary goal of corrective (neutralizing) prism therapy?
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What aspect of visual function is primarily targeted by the three-step program for functional amblyopia management?
What aspect of visual function is primarily targeted by the three-step program for functional amblyopia management?
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In the context of prism therapy, what does overcorrective prism do to the image?
In the context of prism therapy, what does overcorrective prism do to the image?
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Which condition is NOT considered amblyogenic?
Which condition is NOT considered amblyogenic?
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What is the action associated with inverse (training) prisms?
What is the action associated with inverse (training) prisms?
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What condition justifies using inverse (cosmetic) prisms?
What condition justifies using inverse (cosmetic) prisms?
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In the context of hyperopia, what consideration should be taken when dealing with esotropia?
In the context of hyperopia, what consideration should be taken when dealing with esotropia?
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What role does occlusion play in the management of functional amblyopia?
What role does occlusion play in the management of functional amblyopia?
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How are prisms over spectacles corrected for esotropia (ET)?
How are prisms over spectacles corrected for esotropia (ET)?
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What percentage of children aged 3-10 may expect improvement to 20/25 or better through optical correction alone?
What percentage of children aged 3-10 may expect improvement to 20/25 or better through optical correction alone?
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What happens to the measured deviation when prisms are applied to hyperopic eyes?
What happens to the measured deviation when prisms are applied to hyperopic eyes?
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Which factor is associated with less favorable treatment outcomes in functional amblyopia?
Which factor is associated with less favorable treatment outcomes in functional amblyopia?
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When stacking prisms, what is true about their total power?
When stacking prisms, what is true about their total power?
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What defines primary deviation in a non-comitant condition?
What defines primary deviation in a non-comitant condition?
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Which of the following statements regarding the classification of functional amblyopia is correct?
Which of the following statements regarding the classification of functional amblyopia is correct?
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Why must eye muscles of the paretic eye be worked if primary deviation is prescribed?
Why must eye muscles of the paretic eye be worked if primary deviation is prescribed?
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What is the primary treatment goal of vision therapy in functional amblyopia management?
What is the primary treatment goal of vision therapy in functional amblyopia management?
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Which factor complicates treatment for patients with latent nystagmus?
Which factor complicates treatment for patients with latent nystagmus?
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What challenge do early onset and long duration strabismus often present?
What challenge do early onset and long duration strabismus often present?
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Study Notes
ABV II Final Review
- This review covers information for the ABV II final.
- Resources for further study are provided.
- Key topics include prism therapy types, prism positions, prism over specs, stacking prisms, primary vs. secondary deviations, prognostic guidelines, prism for intermittent strabs, prism for constant strabs, general guidelines, treatment of functional amblyopia, management of esotropia, management of exotropia, and management of vertical and non-comitant strabismus
- Important terminology, criteria, and considerations are included.
- Practice questions are provided to assess comprehension.
Prism Therapy Types
- Corrective (Neutralizing): Stabilizes normal sensory fusion by neutralizing demand for controlling fusional vergence.
- Relieving: Stabilizes normal sensory fusion by reducing demand for controlling fusional vergence, often to a level less than full correction.
- Overcorrective: Disrupts anomalous correspondence, forcing the system to look to a "new visual territory".
Prism Positions
- Prentice position (glass prisms): Placed parallel to the eyeball's direction.
- Frontal plane position (plastic prisms): Placed directly parallel to the target's plane.
- Minimum-deviation position (calibrated plastic prism): A calibrated position for accurate prism use.
Prism over Specs
- For exotropias (ETs), minus lenses create a BI effect.
- For esotropias (XT), minus lenses create a BO effect.
- The measured deviation will be larger than the true deviation with myopia and smaller than the true deviation with hyperopia.
Stacking Prisms
- The total power of two stacked prisms is greater than the sum of their individual prism powers.
- Combining prism with a Fresnel prism results in a greater power than the labeled powers.
Primary vs Secondary Deviations
- Non-Comitant:
- Primary deviation: The unaffected eye fixates; prism is over the affected eye.
- Secondary deviation: The affected eye fixates; prism is over the normal eye.
- Comitant: The angle of deviation is the same in all fields of gaze.
Prognostic Guidelines
- Early onset/long duration strabismus often presents as asymptomatic due to adaptations (suppression or anomalous correspondence).
- Must work on establishing normal sensory fusion before prism therapy.
- Recent onset/short duration strabismus presents as very symptomatic with no adaptations, so give prism.
Prism for Intermittent Strabs
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Prescribe the minimal amount of relieving prism to achieve single vision.
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Consider dissociated prism criteria based on percentage criteria of total deviation and vertical deviation.
- Residual Vergence Demand Criteria: This must be known. Values for eso, hyper, and exo deviations are provided.
Prism for Constant Strabs
- Do not use prism if accommodating, AC is present, or if there is peripheral suppression or amblyopia.
General Guidelines for Prescribing Prism
- Avoid relieving or correcting prisms for AC patients - cosmetic prisms are acceptable.
- Carefully consider if relieving prism is appropriate when sensory fusion is present or binocularity can be sustained.
- Do not prescribe relieving or correcting prisms for accommodating patients unless cosmesis.
- Do not use vertical relieving prisms for secondary vertical or DVD.
- Place all, or most of the prism in the front of the paretic eye for nonconcomitant deviations.
Treatment of Functional Amblyopia
- Classifications include strabismic, anisometropic, isoametropic, and deprivation amblyopia.
- More favorable prognosis: anisometropic, hyperopic anisometropia, central fixation.
- Less favorable prognosis: strabismic, myopic anisometropia, and eccentric fixation.
Functional Amblyopia Management
- 3-step program (1) optical correction, (2) occlusion, (3) vision therapy.
- Treatment sequence: refractive correction, patching, and vision therapy.
- Active Amblyopia therapy: Form Recognition/Discrimination, Accommodation, Eye Movement and Fixation, Eye-Hand Coordination, and Binocular Therapy.
Treatment of Anomalous Correspondence
- Sensory Fusion: The process of combining stimuli from both eyes into a single perception.
- Motor Fusion: The relative movements of the two eyes in response to disparate retinal stimuli to obtain or maintain corresponding retinal areas needed to achieve single vision.
- Target Content and Position: Consider the stimulus for sensory and motor fusion separately.
- Target Content: Determined by target characteristics, in most cases, modification of the target is used to break down suppression and stimulate normal sensory fusion.
- Target Position: Stimulus to motor fusion depends on the strabismic angle.
Treatment
- Anti-suppression Therapy: Treatment done at the same time as sensorimotor treatment.
- Anti-suppression Treatment Goals:
- Establish diplopia when strabismic.
- Establish sensory fusion when aligned.
- Stabilize sensory fusion if non-strabismic.
Anti-Suppression Instrument Selection
- Objective angle is used for constant strabismus.
- Slowly reduce the prism to help the patient achieve complete binocular vision in free space.
- Prescribe prism in the opposite direction of the intermittent turn for intermittent strabismus.
Suppression Breakers
- Techniques involve making the patient conscious of the suppression for adults, such as Fast Flashing, Blinking by Patient and Removal of Prism.
Anti-Suppression Training Techniques
- Techniques include visual activities for training patients with suppression.
Management of Esotropia
- Classifications: Divergence Insufficiency XT, Basic XT, and Divergence Excess.
- Prevalence and Signs and Symptoms: Most Intermittent XTs, Basic XTs, and Constant XTs (20-25%).
- Prognostic Factors: Frequency, Magnitude, Comitancy, Laterality, Age of onset, Duration
Management of Exotropia
- Classifications: Convergence Insufficiency XT, Basic XT, and Divergence Excess.
- Prevalence and Signs and Symptoms: Intermittent/Constant/Basic XTs.
Treatment Strategies (Exotropia)
- Motor Stimulation Method for IET and CET, surgical normalization of correspondence
Treatment Strategies (Esotropia)
- Motor Stimulation Method for IET and CET
Treatment Phases
- 1-4: Establish initial optical correction, improve monocular visual functioning, establish normal peripheral fusion, establish normal central and foveal vision.
- 5-6: Prescribe efficient binocular, active home maintenance program/re-evaluate.
VT Strategy for ET
- Obtain normal sensory fusion.
- Expand motor fusion ranges.
- Emphasize divergence.
- Increase quality of sensory responses.
- Improve fusional accuracy.
Considerations in Cases of Paresis
- Paresis can resolve, but sensory fusion can be disrupted.
- Consider HVT and occlusion therapy, as well as prisms and surgery if fusion isn't possible.
Other Non-Comitant Conditions
- Duane's Syndrome: Discuss seating arrangements if necessary, consider horizontal prism.
- Brown Syndrome, and Pattern Deviations: Appropriate treatment approach for the specific type and severity.
Pharmacological and Surgical Treatment
- Pharmacologic treatments for esotropia (Miotics)
- Surgical treatment, which is typically reserved for those cases that are not responding appropriately to other methods of treatment.
Cycloplegics and Penalization
- Near, Far, and Total penalization methods.
Chemodenervation
- Botox.
Surgical Treatment
- Surgical guidelines based on deviation magnitude for strabismus treatment.
Review Questions
- Review questions for assessment on the presented topics.
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Description
Prepare for the ABV II final exam with this comprehensive review. This quiz covers essential topics such as prism therapy types, management of strabismus, and treatment of functional amblyopia. Engage with practice questions to test your understanding and solidify your knowledge.
