Podcast
Questions and Answers
What does the Maddox Wing test primarily assess?
What does the Maddox Wing test primarily assess?
- Cyclo/torsional elements (correct)
- Accommodative status
- Vertical fusion range
- Convergence ability
What does the term 'prism fusion range' refer to?
What does the term 'prism fusion range' refer to?
- The amount of convergence/divergence before fusion is compromised (correct)
- The maximum amount of accommodation
- The amount of visual field available
- The ability to maintain binocularity at varying distances
When assessing prism fusional ranges, which condition may indicate poor control of heterophoria?
When assessing prism fusional ranges, which condition may indicate poor control of heterophoria?
- Normal fusion range
- Increased accommodative response
- Sub-normal fusion range (correct)
- Low diplopia threshold
What is typically fixed during the prism fusion range assessment?
What is typically fixed during the prism fusion range assessment?
What is a practical method for measuring prism fusion range?
What is a practical method for measuring prism fusion range?
What is the definition of heterophoria?
What is the definition of heterophoria?
What does 'NMD' stand for in the context of orthophoria?
What does 'NMD' stand for in the context of orthophoria?
Which test would NOT be used to measure heterophoria?
Which test would NOT be used to measure heterophoria?
What is a key characteristic of heterophoria during a dissociation test?
What is a key characteristic of heterophoria during a dissociation test?
Which factor does NOT contribute to normal binocular single vision (BSV)?
Which factor does NOT contribute to normal binocular single vision (BSV)?
What term describes a rapid and smooth recovery movement when correcting for heterophoria?
What term describes a rapid and smooth recovery movement when correcting for heterophoria?
In describing heterophoria, what does 'size of movement' refer to?
In describing heterophoria, what does 'size of movement' refer to?
What is NOT a characteristic used to describe heterophoria?
What is NOT a characteristic used to describe heterophoria?
What characterizes concomitant heterophoria?
What characterizes concomitant heterophoria?
Which condition describes a failure to converge at near distance?
Which condition describes a failure to converge at near distance?
What defines diverging insufficiency?
What defines diverging insufficiency?
In which of the following scenarios is esophoria present?
In which of the following scenarios is esophoria present?
What is the primary factor in determining if a deviation is eso or exo?
What is the primary factor in determining if a deviation is eso or exo?
Which of the following terms refers to an anomaly occurring at distance?
Which of the following terms refers to an anomaly occurring at distance?
What distinguishes incomitant heterophoria from concomitant heterophoria?
What distinguishes incomitant heterophoria from concomitant heterophoria?
What is true about the fixation distance in relation to concomitant horizontal heterophoria?
What is true about the fixation distance in relation to concomitant horizontal heterophoria?
What is the purpose of using prism flippers in the context of convergence exercises?
What is the purpose of using prism flippers in the context of convergence exercises?
In the Stereogram exercise, what must the patient focus on while holding the card?
In the Stereogram exercise, what must the patient focus on while holding the card?
What type of diplopia occurs with positive relative convergence during the XOP?
What type of diplopia occurs with positive relative convergence during the XOP?
What is the recommended frequency for performing convergence exercises?
What is the recommended frequency for performing convergence exercises?
Which type of correction is suggested for symptomatic diplopia in horizontal heterophoria?
Which type of correction is suggested for symptomatic diplopia in horizontal heterophoria?
What should be avoided during convergence exercises to prevent complications?
What should be avoided during convergence exercises to prevent complications?
What should the base orientation of prisms be to effectively correct for XOP?
What should the base orientation of prisms be to effectively correct for XOP?
What is the primary goal when prescribing prisms for a patient?
What is the primary goal when prescribing prisms for a patient?
What is the first step in formulating a management plan for convergence or accommodative issues?
What is the first step in formulating a management plan for convergence or accommodative issues?
Which of the following is included as a conservative treatment method?
Which of the following is included as a conservative treatment method?
What does a decrease in fusional reserves indicate?
What does a decrease in fusional reserves indicate?
When considering refractive management, which of the following is true regarding lens prescription?
When considering refractive management, which of the following is true regarding lens prescription?
What symptom might indicate a need for intervention in decompensated patients?
What symptom might indicate a need for intervention in decompensated patients?
How should you adjust treatment for patients with a known aetiology?
How should you adjust treatment for patients with a known aetiology?
In orthoptic therapy for horizontal heterophoria, which action should be emphasized?
In orthoptic therapy for horizontal heterophoria, which action should be emphasized?
What is the primary concern when managing a patient with large unresolved deviations?
What is the primary concern when managing a patient with large unresolved deviations?
Study Notes
Terminology
- Orthophoria: no eye movement detected with both eyes uncovered, visual axes are aligned to the fixation target
- Heterophoria: latent deviation, observed when fusion is disrupted.
- Describing Heterophoria:
- Direction of movement (eso, exo, hyper, hypo, cyclo)
- Concomitancy (angle remains the same in all gaze directions, or varies)
- Fixation Distance (6m, 0.3m)
- Size of movement (small, moderate, large, measured in prism dioptres)
- Quality of recovery movement (rapid / slow, smooth / jerky)
- Compensation (if the phoria is resolved without intervention)
- Concomitant Horizontal Heterophoria:
- Esophoria: (ESO)
- Divergence Weakness (D>N) - ESO larger at distance
- Convergence Excess (N>D) - ESO larger at near
- Non-specific (N=D) - ESO equal at distance and near
- Exophoria: (EXO)
- Divergence Excess (D>N) - EXO larger at distance
- Convergence Weakness (N>D) - EXO larger at near
- Non-specific (N=D) - EXO equal at distance and near
- Esophoria: (ESO)
- Prism Fusional Range (Fusional Reserve):
- Measures convergence or divergence before fusion breaks
- Used to assess relative convergence/divergence at different distances (6m, 0.3m)
- Can also be used to assess vertical reserves
- Sub-normal fusion range indicates poor control of heterophoria
- Can monitor progression of heterophoria and treatment efficacy
- Types of Dissociation Tests:
- Maddox Rod
- Maddox Wing (can measure cyclo/torsional elements)
Investigation
- Cover Test: Used to assess speed and quality of recovery, assess for decompensation
- Maddox Rod: Distorts one image, used to assess horizontal and vertical deviations
- Maddox Wing: Introduces two independent objects to assess cyclo/torsional elements
- Near Point of Convergence (NPC): Measures accommodative convergence
- Sheard’s Criterion: Helps determine if heterophoria is the cause of symptoms
- Binocular Visual Acuity: Assesses the ability to see with both eyes working together
- Stereopsis: Assesses the ability to perceive depth
Management
- Conservative Treatment:
- Visual Hygiene Advice: Eliminate any potential causes of decompensation
- Refractive Correction: Optimise spectacle prescription
- Orthoptic Exercises: Active exercises designed to improve fusion and control eye movement
- Prism Relief: Passive prism correction
- Non-conservative/Surgical Treatment: Consider only for large deviations, if all else fails
- Rarely used for heterophoria
- Requires knowledge of extraocular muscles
- Criteria for Treatment:
- Symptomatic: Treat patients with symptoms
- Asymptomatic but at Risk: Treat patients without symptoms, but who are at risk of decompensation and binocular loss
- Patient Motivation: Patient must be willing to participate in treatment
- Enough Time: Adequate time for follow-ups and monitoring
- Colleagues’ Support: Ensure there are other practitioners to assist in treatment if needed
Specific Management Techniques
- Refractive Management:
- Optimise prescription and refractive accuracy
- Consider adding +/- spheres to manipulate vergence
- Orthoptic Exercises:
- Use prism bars, prism flippers, or computer-based exercises to improve fusional vergence
- Utilize stereograms (3 cats) to improve relative convergence
- Prescribing Prisms:
- Use prism as a temporary solution or interim spectacles to correct for deviations
- Prescribe prism base opposite to deviation (base-in for exophoria, base-out for esophoria)
Clinical Findings for Decompensation:
- Symptoms: Patient complaints like eye strain, headaches, or diplopia
- Signs:
- Slow or jerky recovery on cover test
- Reduced fusional reserves
- Reduced binocular visual acuity
- Reduced NPC
- Reduced stereo acuity
- Use Sheard’s Criterion to identify a link between the heterophoria and patient symptoms
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Description
This quiz explores the terminology and concepts related to heterophoria, including its description, types, and characteristics. You'll learn about specific terms like esophoria and exophoria, as well as important factors such as movement direction and fixation distance.
