10. General Clinical Management Guidelines for NonStrabismic and BV Disorders - Clinical Binocular Vision Fall 2026

When there is a Non-Strabismic BV Disorder present, what do we want to do?

Find a functional cure

What is a "functional cure" for a NonStrabismic BV Disorder?

-Equal acuity in each eye

-Comfortable, single BV at all distances

-Stereo

-Normal ranges of motor fusion

-Corrective lenses & up to 5pd of prism may be worn

What are the management options for non-strabismic BV disorders?

-Correction of RE

-Added lens power (plus or minus)

-Prism (vertical or horizontal)

-Vision therapy

What is the benefit of correcting RE for non-strabismic BV disorders?

-Clarity of vision

-Help under or over accommodation

-May decrease the phoria and decrease fusion demand

What are the risks of anisometropia?

-Can decrease stereo

-Significant risk factor for development of accommodative esotropia

->0.50D increases risk of amblyopia

-Increases risk that an accommodative esotorpia will not be aligned with glasses

-Aniseikonia

How to manage refractive error being present in a patient with a non-strabismic BV disorder?

-Prescribe from the cycloplegic refraction

-Reevaluate in 4-6 weeks to see the effect of correction in patients with BV/accommodation dysfunction

Is it possible to cut plus for a patient with a non-strabismic BV disorder?

Yes -- except if the patient has an Eso deviation

When should you prescribe added plus?

-Accommodative dysfunction with Low AA, High Lag, or Difficulty with Minus Lens Test

-Accommodative insufficiency

-Accommodative Lag

-Convergence excess

-Basic esophoria

When deciding whether to prescribe added plus, what should you consider?

Consider patient's ability to wear the lens based on their plus lens findings and BO findings

What is the largest amount of plus that should be prescribed for non-presbyopes?

+2.50 to +3.00

**depending on their working distance

When prescribing plus to a non-presbyope, you want to try to ____ the accommodative response

normalize

If a patient has a +1.00 lag, what is the proper ADD that should be given to this non-presbyopic patient?

You should give patient +0.50D lens in order to normalize accommodative response. If they respond, this is a good fit.

If a patient has a 5pd/D AC/A with a 10eso, what ADD power should we prescribe this non-presbyope?

+2.00. Reassess near phoria after trialing this lens for near work

If a patient has a +2.50 NRA and -1.50 PRA, how would we normalize this by prescribing an ADD power?

+0.50 would normalize this NRA/PRA range

When would we consider prescribing added minus power for a patient with non-strabismic BV disorder?

-High exophoria

-Divergence excess

-Basic Exo

-Normal to High AC/A present

What do you need to consider when prescribing an added minus lens for a patient with non-strabismic BV disorder?

-patients ability to wear the lens

-Accommodative ability (AA, minus lens findings)

-NFV

-Age (young patients only)

-Small amount OK for support during therapy

If you want to prescribe added minus for a non-strabismic BV disorder, how much power should you consider?

1.00-2.00D

What is the effect of adding 1-2D of minus in a patient with a non-strabismic BV disorder?

to increase the stimulus to convergence

When prescribing added minus, what is the goal?

Only prescribe the amount necessary to fuse

Do we want to fully neutralize the deviation that is present by adding minus power in a patient with a non-strabismic BV disorder?

No

How to determine how much minus to rx for a patient with non-strabismic BV disorder?

-CT with minus power in place

-Muscle light and R/G or other test of fusion (Worth Dot)

When you over minus a patient with a non-strabismic BV disorder, should you trial the increased minus power?

Yes

What were the results of the overminus for IXT study?

-Mean distance control improved when wearing overminus at 12m

-Benefit not maintained after tapering, removing the overminus

-Myopic shift from baseline to 12m greater in overminus than the non-overminus group

Effect of Overminus on Refractive Error (Pic)

Effect of Overminus on Refractive Error (Pic)

When would you consider rxing horizontal prism?

-Low to normal AC/A

-Divergence insufficiency

-Basic esophoria

Can angle of prism needed be different at distance and near?

Yes

Can prism be effective for a patient with a vertical deviation in primary gaze?

yes

When is it helpful to rx prism for a patient?

-As a support to begin therapy

-As an alternative to therapy

-At the end of therapy

Should you wean a patient out of prism?

Yes -- gradually decrease prism over time

What are the advantages of rxing prism in patients with non-strabismic BV disorders?

-reduce vergence demand

-relieve symptoms in some binocular anomalies

What are the disadvantages of rxing prism in patients with non-strabismic BV disorders?

-Cannot address accommodation or oculomotor dysfunction or vergence infacility

-Effect on suppression?

-Cosmesis of prism

-Image distortions

-Weight of rx increases

-Limit to how much prism can be put in Rx

-Patient may become dependent on the prism

-Prism adaptation can become a problem

What is prism adaptation?

Angle of deviation will increase after wearing the prism

Who is likely to prism adapt?

-Patients with good sensory & motor fusion

-Some patients with strabismus and suppression/AC

-High phoria

-Reduced vergences

Should you trial prism in patients who you expect to rx prism for?

Yes -- check how long is takes for prism adaptation to occur (30min)

What are some methods used to prescribe horizontal prism?

-Associated phoria

-Saladin's 1:1 rule for esophores

-Sheard's criterion

-Percival's criterion

-Fixation disparity analysis w/ Disparometer, Borish Near Card, or Wesson Card

What are some methods used to prescribe horizontal prism for strabismics?

Muscle balance light and R/G cover test

What is the associated phoria?

Amount of prism that reduced the fixation disparity to 0

How to measure associated phoria at near?

Borish, Saladin card

How to measure associated phoria in distance?

-Computer projection system

-Vectograph slide

-Bernell lantern

What is important to remember when rxing horizontal prism?

You do not want the magnitude of the prism to exceed the dissociated deviation

When you have prism in place, what should you confirm?

Have patient close eyes for 1-2 seconds and then open to see if lines are aligned

What is Saladin's 1:1 Rule for Esophores?

Prescribe BO prism to make esophoria = BI recovery

What is the equation for Saladin's 1:1 Rule for Esophores?

BO (pd) = (Esophoria - BI recovery) / 2

When is it indicated to use Saladin's 1:1 Rule for Esophores?

Indicated for Basic Eso and Divergence Insufficiency

True or False:

The prism of Saladin's 1:1 Rule for Esophores will be split between the 2 eyes

true

What is Sheard's criterion equation?

Sheard's criterion = 2x phoria of compensating vergence

What are the general guidelines for Percival's criterion?

Demand should be in middle 1/3 of fusion range

What are the methods to prescribe vertical prism?

-Associated phoria

-Equate vergence ranges

True or False:

Prescribing for a vertical phoria can help control a horizontal phoria as well

true

What are the non-strabismic BV disorders that can be effectively managed by vision therapy?

-CI

-Vergence infacility

-Accommodative excess

-Accommodative Infacility

-Accommodative insufficiency

-DE

-CE

-Basic Exo

-Basic Eso

-DIvergence Insufficiency

-Vertical phorias