Lec#13: Vergence Treatment Part 2

what is the goal of training septums and apertures?

- increase amplitude and facility of both N and P fusional vergence response

- decrease latency of fusional vergence response

- increase speed of fusional vergence response

aperture rule is used to train what level of fusional vergence?

step vergence

equipment for training with aperature?

- aperture and cards

- flip lenses

- flip prisms

- pointer

if training convergence on the aperature rule adding what lenses will make this harder for the pt?

BIMBOP

Easy way to remember is that when you are training a CI patient, you are training BO because you are forcing their eyes to converge since the image moves from the base inward. Because of this BO is harder. And so BOP plus is harder

which is used to train divergence on the aperture rule?

double aperture used for divergence training

single aperture/ window used for convergence

aperture cards consists of 12 cards which a varying disparities of...?

2.5 to 30pd

cards have either second degree or third degree fusion

how do you train convergence using the aperture rule?

- pt places nose at end of aperture rule

- use kinesthetic awareness of looking close to help pt fuse

- once fusion is achieved, ask pt about clarity, anti-suppression, and depth (inner circle comes closer)

- hold for 10 seconds

- look away and look back to regain fusion as quickly as possible

for divergence you would use double aperture

you are training pt with the aperture rule if they state they see the inner circle coming closer, then you are training

a. convergence

b. divergence

a. convergence

you are training pt with the aperture rule if they state they see the outer circle moving closer, then you are training

divergence

formula for calculating the demand for aperture rule?

card number* 2.5

each card number is the distance in cm between the center of the targets

ex pt fuses card #1

what is the target demand if pt is at 40cm?

1cm/ 0.4m= 2.5pd

which is more difficult

a. tranaglyph and vectogram

b. aperture

aperture is harder b/c there is always a divergence or convergence demand

what is the correct endpoint for aperture rule training?

pt is able to achieve clear single binocular vision with all 12 cards (30pd base out) for convergence and up to card 7 ( 17.5 base in) for divergence

if pt is struggling to fuse with the single aperture rule, how can you help them fuse?

BIM BOP

minus lenses or base in prism

the base in prism will allow the pt to converge less

if pt is struggling to fuse with the double aperture rule, how can you help them fuse?

can help by adding plus lenses as this will relax the eyes and diverge the eyes for the pt

or by adding base out prism will allow the eyes to diverge less as the prism will move the image in for the pt

is aperture rule easier or more difficult than the variable vectograms and tranaglyphs?

more difficult b/c theres always a divergence or convergence demand

eccentric circles/ free space fusion cards A trains

a. step vergence

b. smooth vergence

a. step vergence

goals of eccentric circles?

- increase amplitude and facility

- decrease latency of the fusional vergence response

- increase the speed of the fusional vergence response

equipment for eccentric circles?

opaque or transparent eccentric circles card

flip lenses or prisms

pointer

for eccentric circles/ free space fusion cards A

the pt fuses by _________ in front of the place of accommodation (chiastopic fusion) or ____________ diverging (orthopic fusion) beyond the plane of accommodation

converging

diverging

the eccentric card presents a ______ degree fusion stereopsis target.

a. first

b. 2nd

c. 3rd

3rd degree

what is chiastopic fusion

fusion obtained by voluntarily converging to fixate directly two fusible targets, laterally separated in space, such that the right eye directly fixates the left target and the left eye the right target

how is level 1 of eccentric circles trained?

- pt holds opaque cards 40cm away with A's side by side

- ask pt to "cross their eyes"

- if pt is struggling use localization to show the pt where they have to fixate in space to achieve fusion

- hold fusion for 10 seconds

- as the pt to describe the middle set of the circles

how can you load eccentric circles?

have the pt trombone and maintain fusion

have the pt look away and look back to regain fusion. repeat ten times

separate the cards apart 1cm at a time and repeat

_______ fusion occurs when the vergence plane is in front of the cards.

chiastopic

each eye perceives two targets

when pt converges to the appropriate plane the two middle images over lap and become a fused image in the center

- b/c the eccentricity of the inner circles on the cards retinal disparity will be created and the pt should perceive stereopsis

if converging the A's are together the inner circle appears to float ______ due to uncrossed retinal disparity

away

temporal target displacement--> nasal retinal displacement--> uncrossed retinal disparity

if diverging

and the A's are together, the inner circle appears to float closer due to the crossed disparity (nasal target displacement--> temporal retinal displacement---> crossed retinal disparity

Crossed retinal disparity makes inner circle move __________ pt

a. towards

b. away

towards

Uncrossed makes inner circle move _______ from the pt

a. towards

b. away

away

you are training convergence with eccentric circles. pt states they see the inner circle floating towards them what does they say about the pts eyes? (set up is with A's together)

this is crossed disparity = pt is diverging

the right eye is looking at the right target

the left eye is looking at the left target

if you split the right target in the middle the right eye see's the inner circle mostly to the left side

and thus this is crossed disparity and we know crossed disparity makes things seem closer thus why pt sees the inner circle floating towards them.

you have to instruct pt to try and cross their eyes more to see the inner circle floating away from them aka converging (uncrossed dispairty)

you are training convergence with eccentric circles and set up the cards with the A next to each other. The pt states that they see the inner circle floating away from them, what does this tell us about the pts eye posture?

pt see's inner circles floating away from them we know this is due to uncrossed retinal disparity.

The only way for the pt to see uncrossed disparity is if the right eye is looking at the left target and the left eye is looking at the right target= convergence

if you split the left target down the middle the inner circle is towards the right which is being see by the right eye= uncrossed disparity= inner circle will appear floating away from the pt

convergence --> uncrossed disparity---> circles floating away from the pt

you are training convergence with the B's on the cards set up as next to each other

pt sees the inner circle is floating towards them what does this mean?

floating towards them = crossed retinal disparity and the only way for pt to see the inner circle leaning towards the left with their right eye would be if the right eye was looking at the left target= thus pt is converging

uncrossed is inner circle is floating away from pt = divergence

you are training convergence with the B's on the cards set up as next to each other

pt sees the inner circle is floating away from them what does this mean?

floating away= uncrossed retinal

in order for the pt to be seeing uncrossed retinal disparity the right eye would be seeing the inner circle leaning towards the right

and the left eye is seeing the inner circle leaning towards the left

and the only way for them to see that is if the right is looking at the right target and the left eye is looking at the left target.

Crossed vs. UnCrossed Disparity.

Objects which produce crossed disparity are in front of the object of focus. Objects which produce uncrossed disparity are behind the object of focus.

when the cards are held with the B's together what changes?

the perception of stereopsis of float will be the opposite

true or false

eccentric circles can used for convergence and divergence depending on what the pt does with their eyes.

TRUE

to have the pt train divergence what do you instruct the pt to do with their eyes?

use clear cards

and the pt is asked to relax or diverge their eyes to achieve fusion

if pt is having trouble wit divergence eccentric circles training then how can you help make it easier?

have the pt fixate a target on the wall through the clear eccentric circles

- the pt should start off standing close to the wall and slowly walk backwards until fusion is achieved

what does level 2 of eccentric circles train?

train vergence facility

how is level 2 eccentric circles performed?

switch between chiastopic fusion (hold of ten seconds) and orthoptic fusion (hold for 10 seconds), alternating back and forth several times

continue to separate cards to increase difficulty

how do you calculate the demand for eccentric circles?

target separation in cm/ training distance in meter

what is endpoint for eccentric circles chiastopic fusion?

what is endpoint for eccentric circles orthopic fusion?

fuse cards up to 12cm (30pd PO at 40cm) apart

fuse cards up to 6 to 8cm (15-20BI apart)

switch between chiasoptic and orthopic fusion with cards held 6cm part for 20cpm

eccentric circles can also be used to train what two oculomotor movements?

- saccades: use two or more sets of cards placed at different gazes

- pursuit integration have the pt move the cards laterally or in a circular motion whole maintaining fusion

what is goal for training with lifesaver cards/ free space fusion cards b

increase positive and negative fusion vergence amplitude and facility

decrease latency

increase speed

you are have your pt converge the life saver card and they see the letters popping towards them what does this mean about their eyes?

they are converging

what is the endpoint for lifesaver circles?

pt is able to achieve chiastopic/ orthopic fusion with all of the targets on the card

- pt is able to switch between chiatopic and orthopic fusion with all targets (facility)

exos you want them to first get better at chiastopic fusion

eso you want them to first get better at orthopic fusion

the brewster stereoscope is used to train what fusional vergence level?

step vergence

brewster stereoscope is aka

bioptic and is used for vergence training at distance

brewster is best for training what?

vergence training at distance specifically divergence

what is the brewster stereoscope?

instrument divides physical space into 2 separate areas of visual space, each being visible in one eye

the lenses set the image at optical infinity

same goals

at what distance from the pt does the brewster stereoscope have no accommodative demand?

at 20cm

if you bring the bioptic closer then you can test convergence since you would have a, accommodative demand now

as the target moves closer divergence demand is ________.

is increased and convergence demand decreases

know this; opposite than what you think it would be

how can you make brewster harder for divergerence training?

pt slides card closer and trys to maintain single clear binocular vision

what is the endpoint of brewster stereoscope?

pt achieves single binocular vision with the selected cards at the selected distance

How can you

- supplement fusional vergence technqiue either increasing or decreasing the level of difficulty?

add prisms or lenses during the fusional vergence tests we discussed

can add prism

flippers plus and minus

red/ green or polarized bar reader and corresponding glasses

any binocular target with suppression controls