Intro and Background Flashcards
What is vision?
the derivation of meaning and direction of action as triggered by light
Who is considered a founder of modern vision therapy?
Skeffington
What did Skeffington do?
educated practicing ODs on VT
What are Skeffington’s four circles of vision?
Anti-gravity, centering, identification, speech-auditory
T/F Skeffington’s circles have a hierarchy/order?
false
What is anti-gravity?
“where am I?” “where are my body parts in reference to one another?” the physical and physiological actions taken to determine body presence
Where does anti-gravity information come from?
vestibular information and proprioception
What gives vestibular information?
semicircular canals and otoliths
What gives proprioception information?
the body in general (stretch receptors in muscle and CT) and from afferent fibers from cervical ganglion in upper spine
T/F the fibers of the optic nerve give positional info
true, 20% of the fibers do
What is centering?
“Where is it?”
Can we tell where an object is by where its image hits the retina?
yes
Can we tell where an object is in space based on the posture of the binocular system?
yes, adds depth
How is centering info obtained?
monocular cues to depth and binocularity
What are monocular cues to depth?
size constancy, parallax, texture variations, tau
What is tau?
differing spatial flow with movement; brain can calculate tau value for how fast the angular size changes on the retina, gives sense of change in distance
What is identification?
“what is it?” we identify according to our experience
What does identification involve?
the entire storage and retrieval system of both short and long term memory and the classification systems used to organize stored memories
What is speech/auditory (communication)?
the manner in which we inform ourselves; how we are conscious of our experiences real or imaginary; how we use language to communicate experiences; how we use language to understand what others tell us
What emerges from the four Skeffington circles?
vision, we acquire vision through the interactions we have with the environment over time
T/F we create reality with our sensory systems
true
Piaget’s model of vision development involves two choices to conflict which are…
fight or flight
What are the three levels of Piaget’s fight reaction to conflict?
low level learning, high level learning, Ah-ha development
What is low level learning?
an easy conflict resolution
What is high level learning?
more complex problem solving
What is the ah-ha development?
an epiphany allowing resolution
What conflict resolution level of Piaget’s vision development model is vision therapy under?
Ah-ha development
What is VT?
the arranging of conditions to provide a person with the opportunity to have the necessary meaningful experiences to acquire vision through development and learning
What are four ways to evaluate data?
graphical, analytical, normative, and integrative analysis
What is graphical analysis?
plot clinical findings on a grid to determine whether a patient is likely to have clear, comfortable, single, binocular vision
What is analytical analysis?
developed by OEP, uses a 21 point exam, helps identify small dysfunctions
What is normative analysis?
variation of data based on groups of testing, compared to Morgan’s norms
What is integrative analysis?
compare individual tests to norms, group findings that deviate, and determine the diagnosis (what optometry does)
What are the three basic steps of integrative analysis?
1) compare individual tests to table(s) of expected findings 2) group the findings that deviate from expected 3) identify the syndrome diagnosis based on steps 1 and 2
What are some supplemental tests?
AC/A ratio (distance-near or gradient method), fixation disparity fusional vergence amplitudes, vergence facility, accommodative lag
What are three standard methods for evaluating binocular data?
sheard’s, percival’s and morgan’s
What is sheard’s criterion?
for comfortable BV, fusional reserve= 2x demand (phoria), useful for prescribing prism, especially with exo
What is percival’s criterion?
patient’s data should be in the middle third of their vergence range (phoria between BO and BI), useful for prescribing prism, especially eso
What are morgan’s norms?
compare patient’s test results to the expected findings, note there is an average and an expected range of normal
What happens when findings are outside of normal?
there is a possibility for a diagnosis
What is the maximum amp Hofstetter formula?
25 - (2/5 x age)
What is the average amp Hofstetter formula?
18.5 - (1/3 x age)
What is the minimum amp Hofstetter formula?
15 - (1/4 x age)
Which is the most important Hofstetter’s formula?
minimum expected amplitude
What is the AC/A ratio?
tells how much accommodative convergence there is for a given amount of accommodation
T/F AC/A is different than PFV
true
When is the AC/A ratio useful?
when considering refractive correction and especially near adds
What is the CA/C ratio?
tells how much convergence accommodation there is for a given amount of convergence
T/F CA/C is the same as blur-driven accommodation
false
Why is CA/C rarely used clinically?
there is no set accepted testing protocol, may be used with TBI patients
What are the six areas of data where we look for trends?
PFV, NFV, accommodative system, vertical fusional vergence, oculomotor system, motor alignment and interaction
How do we evaluate PFV? (7)
smooth and step vergence, PFV facility, NRA, BAF with plus lenses, NPC, MEM retinoscopy, FCC
How does NRA evaluate PFV?
plus lenses OU relaxes accommodation and therefore vergence relaxes, patient uses PFV to prevent diplopia
How do we evaluate NFV? (6)
smooth and step vergences, NFV facility, PRA, BAF with minus lenses, MEM retinoscopy, FCC
How do we evaluate accommodation? (5)
monocular and binocular accommodative amp, MAF/BAF with +/- lenses, MEM, FCC, NRA/PRA
How do we evaluate vertical fusional vergence?
supravergence, infravergence, fixation disparity
How do we evaluate oculomotor ability?
fixation status, NSUCO saccades and pursuits, DEM, K-D, visagraph/readalyzer
How do we evaluate motor alignment and interaction?
cover test, phorias, fixation disparity, AC/A ratio, CA/C ratio
What are the three classical categories of visual skills conditions?
BV conditions, accommodative conditions, oculomotor conditions
What are BV conditions?
Duane White: CI, CE, DI, DE, + fusional vergence dysfunction, basic exophoria, and basic esophoria
What are accommodative conditions?
accommodative insufficiency/paresis, accommodative excess/spasm and accommodative infacility
What are oculomotor conditions?
saccadic deficiency, pursuit deficiency, and oculomotor dysfunction
What is vergence dysfunction?
involves disjunctive eye movements in which the visual axes convergence or diverge, resulting in ability of the eyes to accurately fixate and stabilize a retinal image
What is accommodative dysfunction?
interferes with ability of the eyes to focus clearly on objects at various distances, resulting in lack of clear retinal images
What are four possible goals of treatment?
to assist the patient in functioning efficiently, to relieve ocular physical and/or psychological symptoms, to rehabilitate the patient following injury, or to enhance athletic performance
What are methods of treatment?
traditional VT, lenses/prism, surgery
What is traditional VT?
accommodative therapy to increase the amplitude, speed, accuracy and ease of accommodative responses; vergence therapy to enhance sensorimotor fusion
What is prism therapy?
horizontal prisms to eliminate symptoms of asthenopia and reduce fusional vergence demand of vergence dysfunction; vertical prisms to eliminate vertical imbalance
What is surgery for?
to decrease the size of a deviation
What is lens therapy?
plus lenses to reduce the motor demand on either accommodative or vergence systems
