Prelim- Chapter 2 Flashcards
The reaction of an individual to his environment is called behavior. Through the researches of Coghill, Carmichael, Gesell, and many others, it has been shown that the individual makes a defined response of his neuro-motor system to a specific situation. This response is the result of maturation and experience, and is the authentic end product of a total developmental process which works with orderly sequence neurological pattern of organization.
Behavior Patter
Psychologists estimate that 80 percent of the information we obtain from our external environment is by means of our visual pattern. It is the most important portion of the behavior pattern. It is understood that the visual pattern is not separate from the behavior pattern, but rather that it is an important integrated section of its activity. The importance of the visual pattern to the survival of the organism is obvious when we compare the behavior of a person with his eyes closed with his behavior when his eyes are open. It is the dominant sense given to man.
Visual Pattern
external receptors for the visual mechanism.
Eye
The photic stimulus in the eye is converted by means of a________ reaction into electrical impulses in the rods and cones. These electrical impulses proceed to the mid-brain where integration of visual, auditory, kinesthetic and auricular impulses occur.
photochemical
Modification of the visual impulses occurs at three levels.
First, the integrative action of the retina. Polyak has declared that the retina is as complex an integrative center as the brain itself.
Second, integrative action between the various types of receptor impulses at the mid-brain level.
Third, modification of the visual pattern by past experience and emotion of the organism at the cortical level.
Patterns
Behavior pattern
Visual pattern
Accommodative pattern
Corvergence-Pattern.
Accommodation-Convergence Pattern.
______is the mechanism of focusing, designated in its postural set-up by the measurable light value brought to a focus congenial to interpretation. Accommodation is a lenticular-retinal-cortical process which is used by the organism to obtain clear vision.
Accommodation
Developmental research reveals that binocular vision’ develops in the following sequence:
(1) fxation;
(2) coordinated vertical move-ments;
(3) convergence;
(4) monocular accommodation;
(5) binocular accommodation.
Phylogenetic and embryologic considerations reveal that accommodation is more ancient and developed prior to con-vergence,
True
The act of accommodation is a complex pattern which is made up of many subpatterns. Some of these subpatterns can be identified. They are:
tonic accommodation
aberrational accommodation
convergence accommodation
psychic accommodation.
is the lenticular poise under the conditions of far-point fixation with maximum inhibition to activity.
Tonic accommodation
is the range of performance in the accommodative pattern due to the modification in the flux conoid because of spherical and chromatic aberration.
Aberrational accommodation
is the effect of convergence upon the accommodative pattern. Its magnitude is equal to that of accommodative convergence.
Convergence accommodation
There is thus an innervational flow between accommodation and convergence which helps to stabilize the accommodative_____ and the convergence poise at any moment.
poise
is the amount of lenticular accommodation in action due to the emotional and psychological reaction of the subject to the surrounding environment.
Psychic accommodation
provides the mechanism with maintaining single vision.
controls the posturing of the eyes in their orbits and the centering of the total organism in its total environ-ment.
Convergence pattern
This nearest point of single vision is called the________
near-point of convergence.
The near-point of convergence is usually expressed in
inches or diopters.
is the position of the visual axes under conditions of dissociation with farpoint fixation. These are the maximum conditions for inhibition to convergence.
Tonic convergence
is the range of performance in the convergence pattern due to Panum’s area. It is a psycho-physiological range in the convergence pattern.
Fusional convergence
is that amount of convergence in action due to the innervation from accommodation.
Accommodative convergence
is that amount of convergence stimulated, because of the emotional and psychological reaction of the subject, to the surrounding environment.
Psychic convergence
The buffer area in the accommodative pattern is called
hyperopia
The buffer area in the convergence pattern is called
exophoria Hyperopia
Hyperopia operates to protect the mechanism of accommodation against changes taking place between the patterns of accommodation and convergence.
True
Hyperopia exists in the central nervous system. It is measured by the change in the accommodative mechanism induced by a plus lens which does not create an undesirable change in the pattern of convergence.
True
Exophoria éxists in the central nervous system. It is measured by the amount of_____ required to align two dissociated images.
prism base-in
Exophoria is a developmental or maturational relationship within the visual behavior pattern to protect_____
convergence performance.
Any increased dominance in the voluntary (skeletal) or autonomic nervous system will cause increased_____ proceeding to the accommodative and convergence patterns.
stimulation
If increased stimulation is maintained despite the complete absorption of the existing buffer areas (exophoria and hyperopia), the organism must actively inhibit this stimulation.
This is an emergency condition to cope with this problem since clear and single binocular vision must be maintained for organismic survival.
This active state of inhibition in the convergence pattern is called _____.
esophoria
The organism utilizes these areas of tolerance (____) to preserve the status quo of the visual pattern.
exophoria and hyper-
opia
Muscles and glands respond only when they have received efferent impulses from the central nervous system.
Contraction or shortening of a muscle group can occur only when the proper innervational command has been forwarded from the central nervous system.
Therefore, the overt movement of the eyeglobes which we objectively observe when the patient has been dissociated must be due to the innervational pattern issuing from the central nervous system. It can, therefore, be said that exophoria and hyperopia exist in the central nervous system.
True
a. Exophoria is measured by the amount of prism base-in required to align the dissociated images.
b. Exophoria exists in the central nervous. system.
c. Exophoria operates to protect the integrity of the mechanism of convergence against changes taking place between the components of the visual pattern.
a. Hyperopia is measured by the change in accommodation produced by means of plus lenses without producing an undesirable change in the pattern of convergence.
b. Hyperopia exists in the central nervous system.
c. Hyperopia operates to protect the mechanism of accommodation against changes. taking place between the components of the visual pattern.
As long as single and clear binocular vision is being maintained by the organism, the buffer areas in the brain of exophoria and hyperopia will function solely as a means for compensating for the shifts in dominance between the skeletal and visceral nervous systems.
Whenever we interfere with the existence of single binocular or clear vision with our probe bodies (lenses and prisms), these innervational patterns are no longer locked up within the central nervous system and these impulses will proceed to the exteroceptors and cause the overt action which we measure as exophoria (with base-in prism) or hyperopia (with plus lenses).
True
If the organism is forced to maintain concentration for prolonged periods within a restricted area at near, the size of these buffer areas will gradually decrease.
When these buffer areas have been completely utilized, we will have the condition of emmetropia and orthophoria.
True
is not merely the lack of exophoria; it is also a condition of equilibrium.
Orthophoria
is a dynamic condition which can be reached by a visual problem because of the absorption of the original maturational developed exophoria, or the organism has just managed to eliminate an existing condition of esophoria.
Orthophoria
Emmetropia is not merely a passive stage, but rather a _____ condition. It can represent the inefficient downward progression from hyperopia, or it can represent the recovery from a condition of minus projection. Since there is no latitude of performance available, these equilibrium states of orthophoria and emmetropia, are undesirable conditions. Optometrically, we desire to shift the trend toward adequate development of hyperopia and exophoria.
dynamic pivot
What is it (process)
identification (covert pattern)
accommodation (overt pattern)
The greater the demand for precise identification of the target, ie., smaller the print, the more difficult the vocabulary and/or the subjects unfamiliarity with the material, the greater the amount of accommodation that will be stimulated. This is easily observed by means of book retino-scopy, wherein we observe the retinoscopic reflex as the patient reads material at various grade levels. If we give a child with a reading level of the third grade second grade reading material, we will observe a
“with” motion by means of the retinoscope.
