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Biomedical subjects

E Borsting

Publications and source records attributed to E Borsting.

9 recordsLinked to original sources
PubMed2001

All developmental dyslexic subtypes display an elevated motion coherence threshold.

PURPOSE: Psychophysical studies indicate that many dyslexics have a motion-processing deficit. The purpose of this study was to determine whether elevated motion coherence thresholds correlate with the specific dyslexic subtypes as defined by the Boder classification scheme. METHODS: Twenty-one dyslexics (seven dyseidetics, six dysphonetics, and eight dysphoneidetics) and 19 age- and gender-matched controls participated in the study. The dyslexics were identified by an exclusionary approach and then subtyped with the Adult Dyslexia Test or the Dyslexia Determination Test. Motion coherence thresholds were determined with random dot kinematograms composed of signal dots and noise dots. Signal dots moved either left or right on each trial, whereas noise dots moved in random directions. The percentage of dots that comprised the signal was varied randomly on each trial (0 to 21% in 3% increments). Subjects guessed the direction of signal dot motion on each trial (two-alternative forced-choice task). A 75% correct threshold was determined with a Weibull equation fit to the psychometric function. RESULTS: All three dyslexic subtypes had elevated motion coherence thresholds (t-test; dyseidetics p = 0.01, dysphonetics p = 0.039, dysphoneidetics p = 0.048). CONCLUSION: Motion-coherence deficits are not correlated with a specific dyslexic subtype, but, rather, are common to all subtypes. However, some individuals in each of the dyslexic subtypes were found to have normal motion coherence thresholds, suggesting that other factors must be considered to predict the motion sensitivity deficits found in dyslexia.

Adolescent↗
PubMed2001

Management of the Pulfrich phenomenon secondary to pigmentary glaucoma.

BACKGROUND: The Pulfrich phenomenon can cause annoying symptoms for a patient due to a difference in interocular optic nerve conduction. There are very few reports that describe the successful use of tinted lenses as a treatment modality, while the majority of cases in the literature describe the condition without any reference to treatment. Although there are two previous reported cases of the Pulfrich phenomenon secondary to glaucoma, this article relates the first case of a patient with this phenomenon with glaucoma treated by tinted lenses. CASE REPORT: A 42-year-old woman, who was previously diagnosed with asymmetric pigmentary glaucoma, reported dramatic changes in visual perception-especially with driving and motion-related tasks. The evaluation showed asymmetric optic nerve function and a spontaneous Pulfrich phenomenon. The effects of different grades of neutral-density filters over the better eye were quantified by means of the Pulfrich phenomenon, subjective brightness comparison, and the visual-evoked potential. Relief of some of the symptoms from the Pulfrich phenomenon was achieved using an ophthalmic tint. CONCLUSION: The majority of patients (89%) reported in the literature who are symptomatic of the Pulfrich phenomenon received no treatment. This report illustrates that the traditional optometric tool of tinted lenses can be dramatically effective in relief of the motion-related symptoms secondary to the Pulfrich phenomenon in a patient with pigmentary glaucoma.

Adult↗
PubMed1999

Prospective comparison of convergence insufficiency and normal binocular children on CIRS symptom surveys. Convergence Insufficiency and Reading Study (CIRS) group.

PURPOSE: To test the validity-related evidence of a child and a parent symptom survey developed by the Convergence Insufficiency and Reading Study (CIRS) group. METHODS: A case comparison method was used to measure differences in symptoms between 14 school-aged children (ages 8 to 13 years) with Convergence Insufficiency (CI) and 14 children with normal binocular vision (NBV). RESULTS: A pooled t-test indicated that CI children and their parents scored higher than the NBV children and their parents on the child's survey (p<0.001) and parent's survey (p<0.001), respectively. CI children also scored significantly higher (p<0.03) on the Conners' Rating Scale for Parents. CONCLUSIONS: The results suggest that the CIRS symptom survey is a valid instrument for differentiating CI children from those with normal binocular vision. Additionally, children in this age group were able to respond to a broad range of symptom questions associated with CI.

Adolescent↗
PubMed1999

Frequency of convergence insufficiency among fifth and sixth graders. The Convergence Insufficiency and Reading Study (CIRS) group.

PURPOSE: To estimate the frequency of convergence insufficiency (CI) and its related clinical characteristics among 9- to 13-year-old children. METHODS: Fifth and sixth graders were screened in school settings at three different study sites. Eligible children with 20/30 or better visual acuity, minimal refractive error, no strabismus, and exophoria at near were evaluated according to a standardized protocol to determine the presence and severity of CI. These children were classified according to the presence and number of the following clinical signs: (1) exophoria at near > or =4delta than far, (2) insufficient fusional convergence, and (3) receded nearpoint of convergence. Also, children were classified as accommodative insufficient (AI) if they failed Hofstetter's minimum amplitude formula or had greater than a + 1.00 D lag on Monocular Estimate Method retinoscopy. RESULTS: Of 684 children screened, 468 (68%) were eligible for further evaluation. Of these, 453 had complete data on CI measurements and were classified as: no CI (nonexophoric at near or exophoric at near and < 4delta difference between near and far) (78.6%); low suspect CI (exophoric at near and one clinical sign: exophoria at near > or =4delta than far) (8.4%); high suspect CI (exophoric at near and two clinical signs) (8.8%); and definite CI (exophoric at near and three clinical signs) (4.2%). CI status varied according to ethnicity and study site (p < 0.0005), but not gender. The frequency of AI increased with the number of CI-related signs. For CI children with three signs, 78.9% were classified as also having AI. CONCLUSIONS: These findings suggest that CI (defined as high suspect and definite) is frequent (13%) among fifth and sixth grade children. In addition, there is a high percentage of CI children with an associated AI.

Accommodation, Ocular↗
PubMed1997

Not all dyslexics are created equal.

BACKGROUND: Dyslexia is a common disorder that has traditionally been treated as a homogeneous condition. However, recent evidence indicates that it is a heterogenous condition with several subtypes. For example, studies of the visual system indicate that not all dyslexics have a normal visual pathway. Approximately 75% have a processing deficit in the magnocellular pathway. Our previous study indicated that dysphoneidetic but not dyseidetic dyslexics exhibit a magnocellular pathway defect. PURPOSE: The purpose of this study was to expand our previous work by also examining dysphonetic dyslexics. Additionally, the stimulus was altered to enhance detection of a magnocellular pathway defect in any dyslexic subtype. METHODS: Temporal contrast sensitivity functions were determined with a flickering stimulus (5, 10, 15, 20, and 25 Hz) by using a temporal, two-alternative, forced-choice technique. RESULTS: The results indicate that the dyseidetic dyslexics do not have a magnocellular pathway defect, whereas the dysphoneidetics do. Furthermore, examination of the individual dysphonetics indicated that the more severely affected subjects also exhibited a magnocellular pathway defect. CONCLUSION: These results suggest that treatment strategies for dyslexics may need to be modified to take into account their specific subtype.

Adolescent↗
PubMed1996

The presence of a magnocellular defect depends on the type of dyslexia.

Previous studies have identified a magnocellular pathway defect in approximately 75% of dyslexics. Since these experiments have not classified dyslexia into subtypes, the purpose of this experiment was to determine if adult dyseidetic dyslexics or dysphoneidetic dyslexics suffer from a defect in the magnocellular pathway. Nine dyseidetic dyslexics, eight dysphoneidetic dyslexics, and nine normal readers participated in the experiment. Contrast sensitivity functions (CSF) were determined with vertically oriented sine wave gratings (0.5, 1.0, 2.0, 4.0, 8.0, 12.0 c/deg drifting at 1 and 10 Hz) by employing a two-alternative, forced-choice technique. The results of the experiment indicated that dysphoneidetic dyslexics had reduced sensitivity to low spatial frequencies at 10 Hz, whereas dyseidetic dyslexics did not have reduced sensitivity at either 1 or 10 Hz. These results suggest that the type of dyslexia influences whether losses in perception are found which are consistent with a magnocellular deficit.

Adult↗
PubMed1994

Detecting learning-related visual problems in the primary care setting.

BACKGROUND: School-aged children with learning problems are frequently encountered by optometrists. Current research indicates a link between learning problems and certain visual factors that are referred to as learning-related visual problems. As a result, the primary care vision doctor should identify children with learning-related visual problems within the context of a primary care examination. We will present a diagnostic strategy for identifying children with learning-related visual problems. The use of appropriate case history questions and a few additional tests will allow the primary care vision doctor to detect or diagnose the majority of learning-related visual problems within the context of a primary care examination.

Accommodation, Ocular↗
PubMed1988

The role of monocular regions in stereoscopic displays.

Random-dot stereograms of an object standing out from a background always contain a monocular region at the side of the foreground object. This is equivalent to the monocularly occluded part of the background in the real-life viewing of one object in front of another. The role of these monocular regions in the stereoscopic process has not been investigated previously, although it is generally assumed that they are a source of difficulty in stereoscopic resolution because of the unmatchable texture within them. The basis of the present study was a prediction that the presence of texture within these regions would facilitate rather than retard stereoscopic processing. This prediction follows from a hypothesis that stereoscopic processing is initially located at disparity discontinuities. Unmatched regions are only found at such discontinuities, and could serve to locate them.

Attention↗