3. Assessment of Nonstrabismic Binocular Vision - Clinical Binocular Vision Fall 2026

Where to perform version at (distance from patient)?

Penlight/transillum at 30cm

What are versions testing?

-Each diagnostic action field or field of action

-Corneal reflex

What should we do during version testing in down gaze?

hold lids

Overactions are documented as a (+/-) on version testing

+

Underactions are documented as a (+/-) on version testing

-

Should you grade over/under actions on version testing?

Yes -- grade 1 to 4 (smaller to larger)

What is retraction?

Narrowing or widening of the palpebral aperture

What is an A/V Pattern on Version testing?

Change of 10-15pd between up and down gaze

If an over or under action is observed on version testing, what should be done next?

Assess ductions

Diagnostic Action Fields (Pic)

Diagnostic Action Fields (Pic)

What is the diagnostic action field?

position of gaze where a muscle is primary mover of the eye

Diagnostic Action Fields -- Words (Pic)

Diagnostic Action Fields -- Words (Pic)

What is the muscle action?

effect of muscle contraction on rotation of the eye when the eye starts in primary position

Muscle Actions

What is the primary action of the MR?

Adduction

Muscle Actions

What is the primary action of the LR?

Abduction

Muscle Actions

What is the primary action of the IR?

Depression

Muscle Actions

What is the secondary action of the IR?

Extorsion

Muscle Actions

What is the tertiary action of the IR?

Adduction

Muscle Actions

What is the primary action of the SR?

Elevation

Muscle Actions

What is the secondary action of the SR?

intorsion

Muscle Actions

What is the tertiary action of the SR?

adduction

Muscle Actions

What is the primary action of the SO?

Intorsion

Muscle Actions

What is the secondary action of the SO?

Depression

Muscle Actions

What is the tertiary action of the SO?

Abduction

Muscle Actions

What is the primary action of the IO?

Extorsion

Muscle Actions

What is the secondary action of the IO?

Elevation

Muscle Actions

What is the tertiary action of the IO?

Abduction

What is the phoria measurement?

magnitude AND direction of a phoria

At what distances do we test phoria measurements?

Distance and near

True or False:

Sensorimotor exam requires phoria testing in more than one gaze

true

What is comitant deviation?

<5pd with change in gaze or fixating eye.

What is incomitant deviation?

>5pd with change in gaze or fixating eye

What are the techniques that measure phoria?

-CT

-Modified Thorington

-von Graefe phoria test

-Maddox rod

How to do a cover test for phoria measurement?

With best correction

If a patient is underaccommodating, what will be the result on cover test?

-increased exo

-decreased eso

How to keep children engaged while doing cover test?

-Have patient read

-Change the target

-Move the target

-Interesting target & child looks at the details of the target

-Stickers on the nose

What is the target for CT in adults and school aged children?

20/30 letter

What do you need to confirm when doing cover test?

stability of fixation

What do you determine on unilateral cover test?

Is a manifest deviation (strabismus) present?

What should be the duration of the cover test on unilateral cover test?

2-3 sec

If a manifest deviation is present on unilateral cover test, what should you record?

-how often?

-magnitude?

If a manifest deviation is present on unilateral cover test, what test should be done test to neutralize the phoria?

Simultaneous prism cover test (SPCT)

What should be the duration of the cover on ALTERNATE cover test?

1-2 sec

What is the function of the alternate cover test?

estimate the magnitude of the phoria/tropia

What is the goal of alternate cover test?

prism neutralize to consistent reversal

The phoria will reach a stable position after ____ sec

20

You should record the ___ neutral value

High

**8BI moves in, 10 BI neutral, 12BI neutral, 14 BI neutral, 16 BI reversal

Will record 14BI

True or False:

You should repeat unilateral cover test after alternate cover test in cases of a large phoria

true -- may uncover a intermittent tropia or intermittent stabismus

What is the downside to Modified Thorington?

cannot watch eyes as well as with cover test

What should patient be wearing during MT?

best correction

What is the procedure of MT?

-Maddox rod over OD

-Striations will be horizontal

-Penlight centered through the hole in the back of the card

-Measure the phoria with distance and near cards

What is the downside to von Graefe technique to measure a phoria?

cannot watch eyes as well as with cover test

What test is used to measure a cyclodeviation?

Double maddox rod test

How to perform Double maddox rod test?

-Vertically oriented maddox rod placed in front of each eye

-Same color or different colored maddox rods before each eye

-Trial frame should be straight on the patient

-Light present

-Patient will report whether or not images (lines) are parallel

-Patient rotates one or both maddox rods to make the images (lines) horizontal and parallel to each other & parallel to the horizon

-Measure the deviation in degrees

Inward rotation of top of the maddox rod indicated a (incyclo/excylo) deviation

incyclo

Outward rotation of top of the maddox rod indicated a (incyclo/excylo) deviation

excyclo

The double maddox rod test is a _____ test

subjective torsion

Double maddox rod test is good to measure torsion occurring (before/after) visual maturity

after

What is paradoxical torsion?

Occurs when VA paretic eye > nonparetic eye and with fixation preference for paretic eye when dissociated

What are the methods to measure objective torsion (prior to visual maturity)?

BIO, fundus photography

What are the expected distance phoria values in children and young adults?

1 Exophoria

What are the expected near phoria values in children and young adults?

3 exophoria

What are the expected distance phoria values in presbyopes?

1 exophoria

What are the expected near phoria values in presbyopes?

8 exophoria

What is fixation disparity?

images of a binocularly fixed object are not imaged precisely on corresponding retinal points, but are still within Panum's fusional area

Fixation disparity is usually <___’

usually < 6’ (< .25 pd)

How to perform testing for fixation disparity?

-Binocular

-Binocular fusion lock

-Target seen by OD

-Target seen by OS

-Measured in minutes of arc

How will a fixation disparity appear on Wesson Card/Borish Card?

Lines are centered, but appear deviated because of the fixation disparity

How will exo fixation disparity appear on Wesson Card/Borish Card?

Line seen by OD will be to the left and line seen by OS will be to the right (crossed)

How will eso fixation disparity appear on Wesson Card/Borish Card?

Line seen by OD will be to the right and line seen by OS will be to the left (uncrossed)

How to perform Borish near card testing at near?

-Mount on the phoropter

-Polarized glasses worn

-Horizontal scale of vertical lines

-Ten minutes of arc increments (3,2,1,0,A,B,C)

-Scales, numbers, and letters are seen by both eyes

-Upper triangle seen by OD

-Lower triangle seen by OS

-Perceived position of the triangles relative to scale is a measure of the magnitude of the horizontal fixation disparity

How to perform Wesson near card testing at near?

-Polaroid glasses worn

-Not mounted on the phoropter

-Stand lamp used

-25cm for pre-presbyopes

-40cm for presbyopes

-Back arrow (seen by OS) and colored lines (seen by OD)

-Ask patient to tell you where the arrow is relative to the colored lines?

Wesson Near Card (Pic)

Wesson Near Card (Pic)

How to perform Saladin Near Point Balance Card testing?

-Polarized gls worn

-Penlight or backlight used

-18' eso to 18' exo

What is an associated phoria?

amount of prism that reduces fixation disparity to 0

Why would you measure the associated phoria?

-vertical deviation

-prescribing prism

How to measure associated phoria with Borish near card?

-Circles and central x are seen by both eyes (binocular fusion stimulus)

-Lower and left bars seen by OS

-Upper and right bars seen by OD

What is the vertical associated phoria on Borish near card?

amount of vertical prism necessary for Vernier alignment of horizontal lines

What is the horizontal associated phoria on Borish near card?

amount of horizontal prism necessary for Vernier alignment of vertical lines

Can you measure associated phoria with Wesson near card and Saladin Near Point Balance card?

Yes

How to measure associated phoria at distance?

-Vectograph slide (can be used at distance or near)

-Canela visual acuity system

What is forced vergence fixation disparity testing?

Measure fixation disparity while changing the vergence demand

When you increase BO prism on forced vergence fixation disparity testing, what do you expect?

increase exo fixation disparity

When you increase BI prism on forced vergence fixation disparity testing, what do you expect?

increase eso fixation disparity

How to measure forced vergence fixation disparity?

-disparometer

-borish near card

-wesson card

-saladin card

Forced vergence fixation disparity is used to measure the (horizontal/vertical) deviation

horizontal

What is Forced vergence fixation disparity testing useful for?

-unclear etiology of symptoms

-steep slope, large associated phoria and/or significant fixation disparity associated with symptoms

Type 1 Fixation Disparity Curve (Pic)

Type 1 Fixation Disparity Curve (Pic)

Type 2 Fixation disparity

Patient will adapt to BO

Type 3 Fixation disparity

Patient will adapt to BI

Type 4 Fixation disparity

Patient will adapt to BO & BI

What is AC/A?

Change in accommodative convergence that is associated with a given amount of accommodative increase or relaxation

What is AC/A useful for?

-diagnosis

-management

What is important about AC/A testing?

Must control accommodation during tests

What is expected AC/A values?

4/1

What are the forms of AC/A that can be calculated/found?

-Calculated

-Gradient

-Response

To find gradient AC/A, what is the test distance?

40cm with best correction

A patient who is 3pd esophoria is ORTHO when +1.00 flippers are placed in front of the eyes. Assuming 1D of accommodation, what is the AC/A?

3pd/D

To find response AC/A, what is the test distance?

40cm with best correction

How to measure response AC/A?

Simultaneously measure deviation and accommodative response (MEM, Nott, autorefractor)