Distance Phorometry

position the eyes take at rest when looking at a target & all other fusional items have been removed

what does the distance dissociated phoria measure?

break

we must ________ fusion to find a phoria

cover test (gets rid of an image in one eye), Von Graefe (makes it double), Maddox rod/modified Thorington (distorts it), Maddox wing test/stereoscope phoria test (show 2 different objects)

how do you eliminate/break fusion?

fusional vergence

a patient must use their __________ to compensate for their phoria p

positive

if a patient is an exophore, they must use ______ (+ or -) fusional vergence

negative

if a patient is an esophore, they must use _______ (+ or -) fusional vergence

when the pt’s fusional vergence cannot make up for their phoria

when must treatment be implemented for a phoria?

BI

for an exophoria, _____ (BO/BI) prism is used to reduce the stress on positive fusional vergence

BO

for an esophoria, ____ (BO/BI) prism is used to reduce stress on negative fusional vergence

prism, vision therapy

what are the 2 basics of treatment for phorias?

0-2^BI (exophoria)

what is the expected norm value for distance lateral phoria?

ortho (0^)

what is the expected normal value for distance vertical phoria?

vertical

when recording _______ (lateral/vertical) phorias, the eye must be written

fusional vergence

stimulated when there is retinal disparity & it is used to maintain single vision

BI

when testing lateral fusional vergence, you must do _____ (BI/BO) testing FIRST

spillover of convergence stimulation/tonic vergence

why must we do BI testing before BO testing when checking lateral fusional vergence ranges?

diverge, negative

BI prism testing causes the eyes to ________ (diverge/converge) due to _______ (+ or -) fusional vergence

accommodative divergence

when negative fusional vergence runs out, ___________ kicks in, resulting in blur

break

when accommodative divergence runs out, the result is a ______

no

is blur expected on distance BI vergence ranges?

accommodation was not fully relaxed, pt might be over-minused

if pt experiences a blur on distance BI vergence testing, what might this indicate?

converge, positive

BO prism testing causes the eyes to ________ (diverge/converge) due to _______ (+ or -) fusional vergence

accommodative convergence

when positive fusional vergence runs out, ___________ kicks in, resulting in blur

break, phoria

when accommodative convergence runs out, there will be a _____ and the eyes will take up their ______ position

phoria

demand on fusional vergence (D)

BO blur (or break if no blur)

fusional vergence reserve (R) in exophoria

BI blur (or break if no blur)

fusional vergence reserve (R) in esophoria

2x

for comfortable vision, the reserve should be _____ the demand

BO blur (or break)

for exophoria, the ____________ should be 2x the amount of phoria

BI blur (or break)

for esophoria, the __________ should be 2x the amount of phoria

Sheard’s criterion

P= (2/3)D - (1/3)R

equation for prescribing prism for lateral phorias, prism relieves stress on the system

X/5-9/3-5

what are the expected norm values for BI fusional vergence testing?

7-11/15-23/8-12

what are the expected normal vales for BO fusional vergence testing?

less

vertical fusional vergences are expected to be _____ (more/less) than their lateral counterpart

midpoint of vertical fusional ranges

the vertical dissociated phorias are expected to be where?

(base down to break - base up to break)/2 = expected vertical phoria

vertical fusional vergence ranges can be used to check consistency with the vertical phoria with the following equation:

base down

if you get a positive vertical phoria from the expected vertical phoria equation, it is expected to be _____ (BU/BD)

base up

if you get a negative vertical phoria from the expected vertical phoria equation, it is expected to be _____ (BU/BD)

no

do we expect a blur on vertical fusional vergence testing?

BD

measuring supravergence of an eye requires adding _____ (BU/BD) prism

BU

measuring infravergence of an eye requires adding _____ (BU/BD) prism

negative

if a patient recovers past 0 on vertical fusional vergence testing, this should be recorded as a _______ number

3-4^

expected norm value for break on vertical fusional vergence ranges

1-2^

expected norm value for recovery on vertical fusional vergence ranges