ABSTRACT
The use of presently available clinical oculomotor tests of a visual-verbal format are limited because they do not evaluate automaticity of number naming. There is a significant relationship between automaticity of number naming and reading performance. Presented is a new oculomotor test that has a specific method to factor out the consequences of automaticity on oculomotor performance. Normative data for children age 6-13 years is provided, in addition to reliability and validity information. Clinical utilization of this test for diagnosis and management in visually related learning problems is offered.
Subject(s)
Eye Movements/physiology , Saccades/physiology , Vision Tests/methods , Adolescent , Aging/physiology , Analysis of Variance , Child , Educational Status , Humans , Photic Stimulation , Reading , Reference Values , SpeechABSTRACT
This paper summarizes the experimental evidence for a transient system deficit in specific reading disability. Differences have been found between controlled readers and specifically disabled readers in measurements of visible persistence, pattern contrast sensitivity and temporal or flicker contrast sensitivity. This transient system deficit was found in approximately 75% of the specifically reading disabled subjects tested. A further series of experiments failed to demonstrate differences in sustained system function between the two groups. Evidence is also presented which suggests that the visual system deficit precedes the reading disability. Possible mechanisms of the impact of a transient system deficit on reading are discussed.
Subject(s)
Dyslexia/physiopathology , Vision Disorders/physiopathology , Afterimage , Contrast Sensitivity , Flicker Fusion , Humans , Visual PerceptionABSTRACT
Recent research has identified a low-level transient visual system deficit in patients with reading disability. This deficit has been shown to have consequences on higher level perceptual and cognitive functions, including reading. This new information provides optometrists with a theoretical framework to expand the understanding of the relationship between vision and reading. In this paper, traditional concepts are described and an extensive literature review is provided. The impact of these processing deficits on reading performance is discussed based on metacontrast masking and foveal-parafoveal sequential attention models of reading. Clinical implications of transient system function in other clinical entities are also provided.
Subject(s)
Dyslexia/physiopathology , Vision, Ocular , Attention , Dyslexia/therapy , Forecasting , Humans , Vision Screening , Visual PerceptionABSTRACT
To date, there have been few studies to evaluate directly the relationship between binocular visual stress and reading performance. This study employed the cloze procedure to demonstrate the effects of nearpoint stress on performance and efficiency in reading comprehension. Using 19 third year optometry students as subjects, binocular stress was simulated by -2.00 D lenses. Performance, as determined by the time to complete the task, was significantly reduced (p less than .03), but no significant differences in accuracy scores were measured.
Subject(s)
Attention , Concept Formation , Reading , Refraction, Ocular , Adult , Humans , Phonetics , Psycholinguistics , SemanticsABSTRACT
Previous studies indicate that a number of individuals display significant differences between astigmatism measured at farpoint and nearpoint. Adventitious effects, purposeful lenticular changes and adaptations in response to environmental forces are reviewed as possible sources of this astigmatic variability.
Subject(s)
Astigmatism/physiopathology , Environment , Accommodation, Ocular , Astigmatism/pathology , Cornea/pathology , Cornea/physiopathology , Eyeglasses , Humans , Lens, Crystalline/pathology , Lens, Crystalline/physiopathology , VolitionABSTRACT
Four case reports are presented with apparent accommodative influences on the nature of astigmatism. The clinical implications of this phenomenon are discussed.
Subject(s)
Accommodation, Ocular , Astigmatism/physiopathology , Adolescent , Child , Female , Humans , MaleABSTRACT
An anomalous horizontal forced-vergence fixation disparity curve in the shape of the letters V or U is presented. This phenomenon is associated with an increase in eso fixation disparity with base-out prism. This response is shown to be related to instructional set. Intrusion of voluntary vergence is suggested as the most likely basis for this effect.
