9. Case Analysis and Diagnosis (Management of NonStrabismic BV Disorders) - Clinical Binocular Vision Fall 2026

Describe the Deviation of Convergence Insufficiency

≥4∆ greater XP at near than at distance

Describe the NPC of Convergence Insufficiency

≥ 6cm break

Describe the PFV of Convergence Insufficiency

≤ 15∆ BO break or Sheard’s not met

Describe the vergence facility of Convergence Insufficiency

≤ 10cpm with difficulty fusing BO prism

Describe the NPC of Convergence Deficit

≥ 6cm break

Describe the PFV of Convergence Deficit

≤ 15∆ BO break or Sheard’s not met

Describe the vergence facility of convergence deficit

≤ 10cpm with difficulty fusing BO prism

Describe the Deviation of Divergence Insufficiency

Eseo greater at distance than at near

Descsribe the NFV of Divergence Insufficiency

Sheard's for distance vergence not met

To meet Convergence Insufficiency criteria, what must be met?

≥4∆ greater XP at near than at distance

AND

1 other criteria (PFV, NPC, Vergence facility)

To meet Convergence Deficit criteria, what must be met?

≥ 6cm break

-1 other criteria (PFV, vergence facility)

To meet Divergence Insufficiency criteria, what must be met?

-Eso at distance

-NFV deficit

Describe the Deviation of Basic Exophoria

At least 4pd exophoria at distance and near with a difference of no greater than 3pd

Describe the NPC of Basic Exophoria

≥ 6cm break

Describe the PFV of Basic Exophoria

≤ 15∆ BO break or Sheard’s for near vergence not met & Sheard’s for distance vergence not met

Basic exophoria will have difficulty with what lens on binocular facility testing?

Will have trouble with plus lens

To meet Basic Exophoria criteria, what must be met?

-At least 4pd exophoria at distance and near with a difference of no greater than 3pd

-NPC reduced

-PFV reduced

Describe the Deviation of Basic Esophoria

At least 3pd esophoria at distance and near with a difference of no greater than 2pd

Describe the NFV of Basic Esophoria

< 8pd BI or Sheards not met for distance and near vergence

Basic esophoria will have difficulty with what lens on binocular facility testing?

minus lens

To meet Basic Esophoria criteria, what must be met?

-Eso at distance and near

-NFV reduced or Difficulty with minus lens flippers

To diagnose fusional vergence dysfunction, what must be present?

Vergence amplitudes: ≤ 15∆ BO break or Sheard’s not met

& BI < 8∆ break or Sheard’s not met

OR

Vergence facility: ≤ 10cpm with difficulty fusing BO

AND BI prism

Fusional vergence dysfunction patients will have difficulty with what lens on binocular facility testing?

Both plus and minus lenses

What are the common symptoms of convergence excess?

-Significantly higher scores on CISS vs those with normal BV

-CISS score = 16+ in young adults

-Symptoms w/ near work

-Asthenopia, HAs, ocular burning/tearing

-Intermittent blurred vision and diplopia

-Inability to sustain and concentrate, words move on the page, sleepiness when reading, decreased comprehension over time, slow reading

-Symptoms get worse throughout the day

-Often longstanding and chronic

What are the common signs of convergence excess?

-Greater esophoria at near than at distance

-Decrease NFV at near

-High Lag of accommodation

-Generally good stereo

-May have a vertical deviation (40%)

-Intermittent suppression

-Low PRA

-Reduced binocular accommodative facility and difficulty with minus lenses

-Eso fixation disparity at near

If convergence excess is left untreated or inadequately treated, what may happen?

May decompensate to strabismus (accommodative esotropia)

What are the DDx of convergence excess?

-Functional disorders

-Hyperopia

-Underlying pathology (spasm of accommodation/convergence)

Patients with convergence excess have a ____ prognosis

excellent

Do you want to correct any uncorrected refractive error in a patient with convergence excess?

Yes -- with full cycloplegic refraction

What is the management of convergence excess?

-Add lens power for near

-Measure gradient AC/A

-Bifocal vs reading Rx

-Vision therapy (12-24 sessions)

For patients with significant Eso at distance and near (greater at near), they may also need (BO/BI) prism

BO

Describe the deviation with convergence excess

≥ 3pd

Describe the divergence amplitude at near (NFV) with convergence excess

< 8pd divergence (BI) break or Sheard's not met

Describe the vergence facility with convergence excess

≤ 10cpm with difficulty fusing BI prism

Individuals with convergence excess will have trouble with the (plus/minus) lenses on binocular facility testing

minus

What is the average deviation for divergence excess?

29pd at distance; 13pd at near

divergence excess is frequently an ______ at distance

intermittent strabismus

What are triggers for divergence excess being an intermittent strabismus at distance?

-inattention

-fatigue

-illness

-daydreaming

**eye turns out during these activities

What are the 2 forms of divergence excess?

-true DE

-simulated DE

What are the common symptoms of divergence excess?

-Parents report that one eye will turn out at times

-Asthenopia or photophobia

-Possible diplopia

-Child closes one eye in bright light

-Occasional near point asthenopia (often none are present)

What are the common signs of divergence excess?

-Greater exo at distance than near

-Greater frequency of exo deviation at distance comitant

-Suppression and/or HAC at distance (if strabismus is present)

-Normal NPC

-Inadequate compensating (positive) vergence for deviation

-Inadequate NFV

-Eso fixation disparity at near

-Inferior oblique overaction may be present

-No primary vertical deviation

-Normal stereo at near

-High AC/A

What are the DDx for divergence excess?

Functional disorders (Basic Exo, Simulated DE, CI)

Can therapy be successful in treatment of divergence excess?

Yes -- 24-36 sessions are needed and 82% of patients were successful in eliminating intermittent strabismus and asthenopia

What are the negative prognostic factors for treatment of divergence excess with therapy?

Large deviation

Large vertical

Noncomitancy

What is the typical management of a divergence excess patient?

-Added minus for full time wear in young patient

-Sx

Describe the deviation in divergence excess

Exo greater at distance than at near

Describe the fusional vergence ranges for divergence excess

Sheards for distance PFV not met

What are the common symptoms of a vertical phoria?

-HAs and asthenopia

-Blurred vision

-Diplopia

-Frequent loss of place when reading (skipping or repeating lines)

-Motion sickness

-Difficulty attending/concentrating during sustained visual tasks

-atigue/sleepiness during sustained visual tasks

What are the common signs of a vertical phoria?

-Head tilt

-Decreased horizontal fusional ranges (positive and negative)

-Depending on the duration of the vertical deviation, vertical fusion ranges may be decreased or exceptionally large

What are the conditions that can be associated with a vertical deviation?

-dyslexia

-learning disability

Diplopia presents secondary to a vertical phoria when?

-Vertical rectus abnormalities

-Oblique dysfunction

-Skew deviation

-CN III px

-CN IV px

-Ocular myasthenia

-IO and SO overaction

What is the proper management of vertical phoria?

-Vertical prism of 0.75pd or more

-Vertical fusion therapy