8.1.1 Flashcards
What is the purpose of the cover/uncover test
Detects tropias
What is the purpose of the alternating cover test
Detects phorias
What is purpose of OM test
Evaluates EOM function and gaze related missalignments
What is the purpose of Maddox rod test
Assess baby anomalies and assess DIP
Identifies latent deviations when fusion is distrupted
Determines if DIP is being caused by an ocular misalignment
Determines if misalignment is consistent in all gazes(comitant) or varies (incomitant)
What is a Maddox rod?
A series of parallel cylindrical lenses.
How is the Maddox rod typically positioned in the test?
Horizontally or vertically.
What does the patient focus on during the Maddox rod test?
A point light source at a set distance.
What are the typical distances used for the Maddox rod test?
- 6 meters for distance
- 33 cm for near.
What does the Maddox rod do to the light for the covered eye?
Converts the light into a line image.
What does the uncovered eye see during the Maddox rod test?
The actual point of light.
What does the patient report in the Maddox rod test?
The relative positions of the line and the light.
What will a px with exophoria see in a Maddox rod test ?
The line appears to the opposite side of the light when the Maddox rod is over the covered eye
For example, if the Maddox rod is over the right eye and the line is seen to the left, it’s exophoria.
What will a px with esophoria see in Maddox rod test ?
The line appears on the same side as the covered eye when the Maddox rod is used
For example, if the line is seen to the right when the Maddox rod is over the right eye.
What indicates hyperphoria in a px with Maddox rod testing
The line appears below the light, indicating the covered eye is higher
What indicates hypophoria in Maddox rod testing
The line appears above the light, indicating the covered eye is lower
What does a rotated line indicate in Maddox rod testing
Cyclophoria, which is a torsional misalignment
What causes cyclophoria?
Oblique muscle issues
How can prisms be used in relation to deviations in Maddox rod testing
Prisms can be used to neutralize the deviation by aligning the line and dot
What is the purpose of quantifying misalignment in prism diopters?
To measure the degree of deviation
What is the primary purpose of the Maddox Rod Test?
To dissociate the eyes and detect phorias and measure ocular misalignment in horizontal and vertical planes.
The test involves the patient looking at a point light source with a rod placed in front of one eye.
How does the patient participate in the Maddox Rod Test?
The patient looks at a point light source while comparing the line generated by the rod to the light.
This comparison helps in assessing ocular alignment.
What does the Maddox Wing Test assess?
It assesses both horizontal and vertical phorias/tropias in a more natural binocular presentation.
The test uses wings with a target in the middle for assessment.
How does the Maddox Wing Test differ from the Maddox Rod Test?
The Maddox Wing Test provides a more natural binocular presentation of misalignment.
It allows for a controlled assessment of eye alignment in real-world conditions.
What dynamic method does the Maddox Wing Test use?
It uses prisms and target alignment to test a patient’s binocular alignment.
The patient looks at a fusion target and adjusts to align the images.
True or False: The Maddox Rod Test is used for assessing binocular alignment dynamically.
False.
The Maddox Rod Test is primarily for dissociating the eyes rather than dynamic assessment.
What is the purpose of the Maddox Wing Test?
To assess horizontal and vertical alignment of the eyes and evaluate fusion and stereopsis
The test is crucial for diagnosing conditions like exophoria and esophoria.
What equipment is used in the Maddox Wing Test?
Maddox Wing device, horizontal and vertical prisms, target (light source or cross)
The device allows the examiner to assess eye alignment effectively.
How is the patient positioned during the Maddox Wing Test?
The patient is asked to focus on the target and maintain fixation on the central object
Proper positioning is essential for accurate assessment.
What does exophoria indicate in the Maddox Wing Test?
Outward deviation of the eye
This is detected when the target appears displaced to the right or left.
What does esophoria indicate in the Maddox Wing Test?
Inward deviation of the eye
Esophoria is identified when the target appears displaced to the right.
What is assessed first during the Maddox Wing Test?
Horizontal misalignment using horizontal prisms
This step is crucial before evaluating vertical alignment.
What is hyperphoria?
One eye is positioned higher than the other
This condition is assessed after evaluating horizontal alignment.
What is hypophoria?
One eye is positioned lower than the other
This condition is also assessed after horizontal alignment.
What does trouble aligning images during the Maddox wing test suggest?
An issue with binocular fusion or lack of stereopsis
This can lead to symptoms like diplopia.
How is the amount of deviation measured in the Maddox Wing Test?
In prism diopters based on target displacement
This quantifies the degree of misalignment observed.
Fill in the blank: The Maddox Wing Test helps evaluate _______.
fusion and stereopsis
Proper evaluation is crucial for understanding binocular vision.
What indicates a hyperphoria during the test? Maddox wing
Target displaced upward
This suggests one eye is higher than the other.
What indicates a hypophoria during the test? Maddox wing
Target displaced downward
This suggests one eye is lower than the other.
What is Divergence Weakness?
A condition where the eyes have difficulty moving outward to maintain alignment for far vision.
Symptoms include blurred vision, double vision, and eye fatigue when looking at distant objects.
What causes Divergence Weakness?
Weak lateral rectus muscles or neurological issues.
It can be diagnosed through binocular vision tests.
What are common treatment options for Divergence Weakness?
- Vision therapy to strengthen eye muscles
- Prism glasses
- Eye exercises
These treatments aim to improve the ability to diverge.
What is Divergence Excess?
A condition where the eyes diverge excessively, causing outward misalignment or exotropia, particularly when focusing on distant objects.
This condition leads to noticeable outward eye deviation.
What causes Divergence Excess?
Overactive lateral rectus muscles or neurological dysfunction.
It may result in symptoms such as double vision at distance and eye strain.
What are common symptoms of Divergence Excess?
- Double vision at distance
- Eye strain
- Noticeable outward eye deviation
These symptoms occur especially when focusing on far objects.
How is Divergence Excess diagnosed?
Similar to Divergence Weakness, involving prism testing and binocular vision assessments.
Diagnosis focuses on evaluating eye alignment and function.
What are common treatment options for Divergence Excess?
- Prism glasses
- Vision therapy to improve convergence
- Surgery to adjust muscle function (in severe cases)
Treatment aims to correct excessive outward movement of the eyes.
True or False: Divergence Weakness is characterized by excessive outward movement of the eyes.
False
Divergence Weakness is characterized by difficulty diverging.
Fill in the blank: Divergence Excess is marked by excessive _______ of the eyes.
outward movement
This is in contrast to Divergence Weakness.
What does the AC:A ratio represent?
The relationship between accommodation and convergence
Accommodation refers to the eye’s ability to focus on near objects, while convergence refers to the inward movement of the eyes for maintaining binocular vision.
What is Accommodation (A)?
The eye’s ability to change its focus to view objects at varying distances
Typically involves the ciliary muscles.
What is Convergence (C)?
The inward movement of the eyes necessary for proper alignment and binocular vision
Essential when looking at near objects.
How does the AC:A ratio quantify eye function?
Indicates how many prism diopters of convergence occur for each diopter of accommodation
For example, a ratio of 4:1 means 4 prism diopters of convergence for every 1 diopter of accommodation.
What is a typical normal AC:A ratio?
Around 4:1
This means for every 1 diopter of accommodation, the eyes converge by about 4 prism diopters.
What is the first step in measuring the AC:A ratio?
Accommodation Measurement
The patient focuses on a near target and their accommodation is measured using a retinoscope.
What is the second step in measuring the AC:A ratio?
Convergence Measurement
This involves measuring the amount of convergence as the patient focuses on the near target, typically using prism bars.
What does a normal AC:A ratio indicate?
Healthy eye coordination for near tasks
Typically around 4:1.
What does a high AC:A ratio suggest?
Convergence excess
Indicates over-convergence for near objects, potentially leading to eye strain or double vision.
What does a low AC:A ratio suggest?
Convergence insufficiency
Indicates the eyes do not converge enough for near tasks, leading to difficulty maintaining clear vision.
Why is the AC:A ratio clinically important?
It helps diagnose binocular vision problems related to near tasks
Essential for deciding appropriate treatments like vision therapy or prism correction.
Fill in the blank: The AC:A ratio is expressed as a ratio such as _____.
4:1 or 3:1
True or False: A higher AC:A ratio always indicates a healthy visual system.
False
What does ARC stand for?
Anomalous Retinal Correspondence
How does ARC relate to binocular vision?
It refers to an abnormal relationship between the two eyes’ visual fields when there is strabismus.
What is strabismus?
Misalignment of the eyes.
What adaptation occurs in ARC?
The brain shifts the foveal correspondence between the two eyes.
What does the brain achieve through ARC despite eye misalignment?
Single binocular vision
In a normally aligned eye system, where do both eyes have corresponding points?
On the retina (the fovea)
What happens to corresponding points on the retina in ARC?
They shift to an abnormal area.
What is the result of the brain’s adaptation in ARC?
The brain combines the images into a single fused image.
Fill in the blank: ARC allows a person with strabismus to achieve _______.
single vision
What are the two types of ARC?
- Foveal ARC
- Perifoveal ARC
What characterizes Foveal ARC?
The fovea in the misaligned eye has an abnormal correspondence with a point other than the fovea of the non-deviated eye.
What characterizes Perifoveal ARC?
The abnormal correspondence occurs in the area surrounding the fovea.
In which patients is ARC often developed?
Patients with longstanding strabismus.
What types of strabismus can ARC occur with?
- Horizontal (esotropia or exotropia)
- Vertical misalignments
How is ARC typically diagnosed?
During binocular vision testing.
Name one test that can help identify ARC.
- Hering-Bielschowsky Test
- Worth’s Four-Dot Test
- Prism testing
How can ARC impact treatment?
It complicates treatment due to the brain’s adaptation to misalignment.
What may be necessary for patients with ARC?
Vision therapy
What is a goal of vision therapy for ARC patients?
To retrain the brain to recognize normal retinal correspondence.
What is a potential challenge after strabismus surgery for patients with ARC?
The brain may have difficulty adjusting to the new alignment.
