Ophthalmology: Non-Comitant Deviations Part 2

Questions and Answers

What percentage of Divergence Excess cases are actually classified as Pseudo-Divergence Excess?

30-50%

60-90% (correct)

90-100%

10-30%

What characterizes consecutive strabismus?

It is a permanent state of deviation from normal alignment.

It can only occur in adults following surgery.

It is always associated with accommodative ET.

It arises when the deviation differs in direction from pre-existing strabismus. (correct)

Which test demonstrates an increase in near deviation for Pseudo-Divergence Excess?

+3.00D lens test (correct)

Random dot stereopsis

Unilateral occlusion test

Cover test

What is the prevalence range of consecutive strabismus?

4-20% Signup and view all the answers

In Divergence Excess, which factor is NOT commonly a trigger for the condition?

High visual acuity Signup and view all the answers

Which group of patients is most likely to develop consecutive XT after surgical correction?

Patients with high AC/A ratios. Signup and view all the answers

Which of the following statements is true regarding the Occlusion Test results for Pseudo-Divergence Excess?

Increase in near deviation Signup and view all the answers

What is a common sign indicating Divergence Excess?

Winking an eye shut in sunlight Signup and view all the answers

Which statement about dissociated vertical deviation (DVD) is correct?

It occurs spontaneously when the patient is fatigued or inattentive. Signup and view all the answers

Which condition is likely to show a HIGH AC/A ratio?

True Divergence Excess Signup and view all the answers

What is a key characteristic of patients with consecutive XT after hyperopic correction?

They often have moderate to high hyperopia. Signup and view all the answers

How does dissociated vertical deviation manifest during a cover test?

The eyes will drop slowly when first uncovered. Signup and view all the answers

Which deviation is most frequently associated with covariation?

Divergence Excess Signup and view all the answers

Which characteristic is NOT associated with Amblyopia in the context of Divergence Excess?

Absence of Amblyopia Signup and view all the answers

Which condition does NOT contribute to the development of consecutive XT?

Totally accommodative ET with normal binocular vision. Signup and view all the answers

What is expected if true Divergence Excess is present during a +3.00D lens test?

Increase in the near deviation Signup and view all the answers

What are the risk factors associated with the appearance of consecutive XT?

Presence of high hyperopia in ET patients. Signup and view all the answers

Which of the following is least likely to be a factor influencing Divergence Excess?

Significant physical exercise Signup and view all the answers

What condition is also known as an alternating hyperphoria?

Dissociated Vertical Deviation Signup and view all the answers

What is the typical range of refractive error for Refractive Accommodative ET?

+2.00 to +7.00 Signup and view all the answers

What distinguishes Non-Refractive Accommodative ET from Refractive Accommodative ET?

Higher AC/A ratio Signup and view all the answers

Which clinical feature is NOT typically associated with Infantile ET?

Constant strabismus at distance Signup and view all the answers

Which condition is unlikely to occur in Refractive Accommodative ET?

Myopia Signup and view all the answers

What is likely to happen if a deviation is entirely accommodative in nature?

Glasses will completely correct the issue Signup and view all the answers

What characterizes the visual acuity associated with Accommodative ET?

Seldom amblyopia, dependent on aniso frequency Signup and view all the answers

In a case where the right eye refuses to elevate upon adduction but elevates normally upon abduction, what is the most likely condition?

Brown’s Syndrome Signup and view all the answers

A patient experiences double vision primarily while exercising on a treadmill. What condition is most likely indicated by this symptom?

Myasthenia Gravis Signup and view all the answers

Which type of exotropia is characterized by a constant deviation and an associated normal AC/A ratio?

Basic Exo Deviation (BXT) Signup and view all the answers

What is commonly associated with infantile exotropia, especially in patients under one year of age?

Suppression Signup and view all the answers

In which condition does a patient present with unilateral exotropia following significant vision loss in one eye?

Secondary Exotropia - Sensory Signup and view all the answers

Which of the following deviations in convergence insufficiency results in exodeviation being larger at near than at far by greater than 5Δ?

Convergence Insufficiency (CIXT) Signup and view all the answers

What is the potential for obtaining normal, single binocular vision after the treatment of infantile exotropia?

Poor Signup and view all the answers

How does the deviation in secondary sensory exotropia typically present?

Large and constant Signup and view all the answers

What type of nystagmus is commonly found in infantile exotropia?

Latent nystagmus is uncommon Signup and view all the answers

What criterion defines a basic exo deviation?

Normal AC/A Ratio Signup and view all the answers

What characterizes a patient with intermittent exotropia (IXT) and a control scale of 1?

No exotropia unless dissociated, recovers in < 1 second Signup and view all the answers

Which of the following statements about infantile esotropia (ET) is true?

Infantile ET is considered non-accommodative with stable deviation. Signup and view all the answers

What is a common characteristic of convergence excess esotropia?

Larger esodeviation at near than far by > 5∆. Signup and view all the answers

The PEDIG studies indicated what key finding about the variations in infantile ET?

Around 50% are ≥ 40 ∆, emphasizing deviation variability. Signup and view all the answers

What defines the refractive status in patients with infantile ET?

Considered non-accommodative with low-moderate hyperopia. Signup and view all the answers

Which of the following is a potential diagnosis when observing the Cross Fixation Pattern in infants with ET?

Nystagmus Blockage Syndrome Signup and view all the answers

What aspect of infantile ET affects visual acuity?

19% of patients with infantile ET may develop amblyopia. Signup and view all the answers

How does the esodeviation in divergence insufficiency differ from other forms of strabismus?

Esodeviation is greater at far distances than near by > 5∆. Signup and view all the answers

What role does the AC/A ratio play in differentiating types of esotropia?

A high AC/A ratio is found in non-refractive accommodative ET. Signup and view all the answers

Study Notes

Consecutive Strabismus

Defined as a deviation that differs in direction from a pre-existing strabismus; typically seen post-surgery.
Prevalence ranges from 4% to 20%.
Often results from poor sensory fusion or anomalous correspondence before surgery.
Types include:
- Consecutive Esotropia (ET): following surgical correction of Exotropia (XT).
- Consecutive XT: may occur spontaneously or from surgery correcting ET; prevalent in 4-20% of ET cases.

Risk Factors for Consecutive XT

Linked to high hyperopia; Groves study shows patients with hyperopic correction over +7D have increased risk for XT.
Occurs in about 10-20% of ET patients using hyperopic glasses.
Average interval for XT emergence is approximately 20.5 months.
Not seen in those with fully accommodative ET and normal binocular vision potential.

Dissociated Vertical Deviation (DVD)

Characterized by spontaneous upward movement of one or both eyes when fatigued or inattentive.
Cover test will show a slow drop of the eyes when uncovered.
Commonly associated with infantile ET, presenting around 2-3 years of age.
Prism cannot neutralize this condition; it's not an effective treatment.

Differentiating DVD from Vertical Deviation

Normal vergence and accommodation ranges.
Right eye elevation defects in adduction are a key indicator.

Exotropia Classifications

Constant XT: Includes infantile, secondary, basic, and divergence excess XT.
Basic Exo Deviation (BXD): Maintains normal AC/A ratio.
Convergence Insufficiency (CIXT): Exhibits low AC/A ratio with more deviation at near than far.

Infantile XT

Onset typically before 1 year, often associated with neurological syndromes.
Deviation ranges from 30-80∆, typically constant.
Often exhibits DVD and has common occurrences of anomalous correspondence.
The potential for normal binocular vision post-treatment is generally low.

Secondary Exotropia

Sensory XT: Constant XT arising after visual loss in one eye, usually caused by pathology.
Indicative of a large deviation (30-60∆) and occurs with similar frequency as sensory ET.
Prolonged sensory deprivation can disrupt central fusion and lead to diplopia.

Divergence Excess vs. Pseudo-Divergence Excess

60-90% of DE cases are actually pseudo-DE with low AC/A ratios.
Occlusion test results differ significantly between true DE and pseudo-DE.

Tests for DE

Occlusion Test: Unilateral occlusion (30-45 mins) shows increased near deviation for pseudo-DE, no effect in true DE.
+3.00D Lens Test: True DE shows increased near deviation; pseudo-DE does not.

Infantile Esotropia Classifications

Involves normal AC/A ratios and high familial tendency.
Deviation is relatively stable, usually large, and occurs around 3-4 months of age.
Low refractive errors, often non-accommodative; correction has minimal impact on deviation size.

Accommodative Esotropia

Commonly seen from birth to age 7, with the most frequent onset between 2-3 years.
Subcategories include refractive and non-refractive accommodative ET, each with different mechanisms and refractive errors.

Key Differences in Accommodative ET Types

Refractive Accommodative: Normal AC/A with mean refractive error of +4.50D.
Non-Refractive Accommodative: High AC/A with mean refractive error of +2.25D, more significant deviation at near.

Treatment Considerations

If strabismus is fully accommodative, glasses may resolve the issue; leftover deviation implies a non-accommodative component.

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Description

Test your knowledge on non-comitant deviations in strabismus, specifically focusing on consecutive strabismus. This quiz covers the characteristics, prevalence, and factors influencing deviations following surgical interventions. Gain insights into the complexities of post-surgical outcomes in eye alignment.