ABV_Test1 Flashcards
What is the AC/A ratio formula?
PD(cm) + target distance (m) x (near phoria - distance phoria)
What sign do you use for esophorias?
Plus
What sign do you use for exophorias?
Minus
What is the same value for AC/A ratio when you contain the same measurement for phorias at distance and near?
Distance PD
List the three ways in getting AC/A ratio?
Calculated method
Gradient
Modified Thorington
What is the standard measurement taking when measuring CA/C ratio?
6 prism diopters per 1 meter.
What are two ways to get CA/C ratio?
BCC & placing 6pd in eye
Wessin Fixation disparity card.
What does DOG stand for?
Difference of Gaussian card
What is the norm for CA/C ratio?
0.50D/6 pd
What is the Morgan norm for NRA?
+2.00 to +2.50D
What is the Morgan norm for PRA?
‐2.37 up to ‐4.00
Why does blur occur during NRA testing?
Blur.
- Accommodation can no longer relax
- PRV can no longer be stimulated
How do you test if vergence system or accommodative system is to blame for NRA?
Cover one eye.
If target is clear from the blur, then vergence is to blame.
Which ptx will have trouble with NRA testing?
- Those who cannot relax their accommodation
2. Those who have trouble converging
What does it mean if the endpoint is double for NRA?
Ptx is highly exophoric with low PRV values
What does a low NRA value mean?
- Ptx has difficulty relaxing accommodation
2. Highly exophoric with low PFV reserves
What does a high NRA value mean?
Ptx has latent hyperopia with a big lag of accommodation.
What can cause a big lag of accommodation
Over-minusing a ptx
Underplussing a ptx.
Are NRA/PRA an accommodative test or vergence test?
Accommodative test; however u cannot ignore the effects of the vergence system
What happens if vergence is allowed to move with accommodation during NRA or PRA testing?
Diplopia!
What is the cause of blur during PRA testing?
- Accommodation can no longer be stimulated
2. NRV cannot be stimulated any further “independent” of accommodation
What’s the cause if endpoint is diplopia durng PRA testing?
Ptx is higly esophoric at near with low NRV values
What test are you doing if ptx is suppressing an eye during PRA test?
Minus to blur amplitude of accommodation
Give me two reasons a ptx may have low PRA values?
- Ptx has problems stimulating accommodation
2. Ptx may have high esophoria at near, thus hard to diverge eyes.
Caleb, refer to examples on pg 12 of Core concepts
Si senor
T/F?
There is no change in accommodation from the uncorrected to corrected sate for a myope.
True
NRV testing is specific for what?
The point just before the blur.
Why may blur result for NRV testing?
- Low divergence reserves like in esophoria
2. Accommodation not being stimulated
Why do the eyes shift when prism is introduced?
To maintain normal retinal correspondence.
Vergence movements are made.
Why may blur result for PRV testing?
- Low convergence ability like in high exophoria
2. Difficulty relaxing accommodation.
What is total positive vergence?
From the start of the test to the diplopia finding?
Would an esophoric ptx or exophoric ptx have trouble converging?
Exophoric
Give me the two clinical applications for a high PRV value relative to NRV value?
- Near esophoria
2. Difficulty stimulating accommodative system.
What are the three things used to describe ocular motor dysfunction?
Fixation
Pursuit
Saccades
Which skill develops first in a human; accommodation or eye movement skills?
Accommodation.
Throw BV skills n the same category as well.
There is a high prevalence of OMD in children with learning disabilities and emotional disorders, as
well as in children without learning disorders and emotional disabilities
Cierto
Name the three researches for OMD dysfunction part 1
Sherman
Hoffman
Lieberman
Between SCCO and NSUCO, which test is more standardized?
NSUCO
Not Sitting
What test monocularly tests for fixation?
UCT
Does a higher ratio result in a lower percentile rank?
Claro que si!
Define Type 1 outcome on DEM test?
Patient performs within the normal range, greater than 35th percentile, for both the vertical and the horizontal sections as well as makes an acceptable amount of errors for their age.
Define Type II outcome on DEM test?
Patient has OMD only. Patient passes vertical section.
Patient is below average on horizontal portion.
THe patient also shows a high ratio
Type III?
Patient has an automaticity problem only.
Patient shows below avg performance on both the vertical and horizontal portion of the test.
Ratio is normal
T
Type IV?
Paient has automaticity and OMD problem.
Horizontal time performance is worse than that of the vertical performance giving an abnormally high ratio.
Can you test automaticity with the King-Devick test?
NOPE
What are the name of the researchers that did a study on DEM?
Tassinari and DeLand
Which saccadic test would you use to monitor ptx in vision therapy?
Visigraph
Name the researcher that did their research in Visigraph?
Colby
T/F
Pierce test evaluates gross saccadic movements?
True
These gross movements are bigger than that of King Devick test
List the criteria that the ptx is graded on for NSUCO testing
Ability
Accuracy
Body/Head Movement
Why is head movement so horrible?
- It expends more energy than is needed
2. Disorientation in space
At what age should pursuits in children be smooth?
8 years of age.
What two things can a pt with large pursuits mean?
- Inability to sustain attention
2. Distracted by objects in the periphery
Define motor overflow
Fidgeting or unrelated verbalization during ocular motor testing
If you find the patient struggling with the pursuit task, what should you tell the ptx to do next?
Point to the target.
This adds kinesthetic support
What does it mean if a ptx scores improves with kinesthetic support?
An organic cause to a pursuit problem
What does better monocular performance than binocular performance suggest?
A binocular problem
What does a better binocular performance suggest?
That adequate monocular performance has not been achieved
That there is a fragile pursuit system
Define Visual therapy
Involves the use of therapeutic procedures to modify visual function
Define developmental vision training
Used to help the development of proper visual function in children
Define preventative vision training?
Prevents visual problems that would otherwise occur
Define Rehabilitative vision training?
Used to help with vision conditions that have already been identified
Define Enhancement visual training?
Used to enhance visual skills for sports, work, or academic demands
What is the name of the author who identified four areas of vision therapy?
Peachy
Define BI-ocular technique?
Simultaneous Perception.
Done with both eyes open but ptx is not fused.
In what context is afterimage used in OMD treatment?
As a form of feedback.
You are tagging the pt’s fovea by giving visual feedback to help him with the accuracy of the pursuits
Define phoria?
Latent deviation from the eye
What system is responsible for making the deviation latent?
Vergence system!
Central fusion and alignment is possible as a result
Define tropia?
Manifest deviation of the eye.
The vergence system cannot compensate for the deviation.
A tropia is not necessarily cosmetically apparent.
What four things does the UCT reveal?
Frequency
Magnitude
Laterality (which eye)
Direction of the deviation
Define frequency?
Ptx may be fused for some of the time in the UCT test. Ptx may not be fused.
Name some fixation tests?
Dotting O's Stick in Straw A-O Star Thumb fixations Stationary Pegboard
