Vigabatrin (VGB) is an antiepileptic drug approved for pediatric patients with infantile spasms. VGB is associated with visual field reductions in 30-50% of adults taking the drug. The amplitude of the 30-Hz flicker electroretinogram (ERG) is recommended for screening young children on VGB treatment. To determine if standard ERG tests for VGB toxicity are correlated with visual field reductions, 22 individuals who were previously on VGB underwent visual assessment. This study also validated the use of high-resolution OCT for detecting structural changes associated with VGB toxicity. This study demonstrates that the ERG was associated with visual field loss, as measured along the temporal meridian. The retinal nerve fibre layer (RNFL) was attenuated in all children who showed a reduction in the visual fields indicating that RNFL attenuation may be a sensitive marker for VGB toxicity. We recommend using serial OCTs to monitor VGB toxicity since it is fast and non-invasive.

Vigabatrin (VGB) is an antiepileptic drug approved for pediatric patients with infantile spasms. VGB is associated with visual field reductions in 30-50% of adults taking the drug. The amplitude of the 30-Hz flicker electroretinogram (ERG) is recommended for screening young children on VGB treatment. To determine if standard ERG tests for VGB toxicity are correlated with visual field reductions, 22 individuals who were previously on VGB underwent visual assessment. This study also validated the use of high-resolution OCT for detecting structural changes associated with VGB toxicity. This study demonstrates that the ERG was associated with visual field loss, as measured along the temporal meridian. The retinal nerve fibre layer (RNFL) was attenuated in all children who showed a reduction in the visual fields indicating that RNFL attenuation may be a sensitive marker for VGB toxicity. We recommend using serial OCTs to monitor VGB toxicity since it is fast and non-invasive.

Thesis (Ph. D.)--York University, 2001. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 178-190). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ66349.

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Theses (M.S.)--Ohio University, December, 1980. / Title from PDF t.p.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 172-179).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 106-108). Also available via the Internet.

Perimetry is essential to identify visual field defects in disorders of the visual pathways. In compliant adults, automated static perimetry (ASP) is the preferred method of visual field assessment. However, children under 10 years have difficulty with the visuo-motor task and constant fixation required. Manual kinetic perimetry is often used for children as it can be adapted to a child’s age. However, it suffers from many of the problems inherent to ASP. In infants perimetry is limited to the “confrontation” technique which can be imprecise and does not generate quantitative data. The lack of reliable ASP in children and quantitative perimetry in infants is a longstanding clinical problem. The aims of this research were to (i) develop, and (ii) clinically evaluate, a technique for ASP in children which utilises “eye tracking”. The first part of this research was concerned with the development of the technique, termed “Saccadic Vector Optokinetic Perimetry” (SVOP). The system comprises a personal computer, display screen, and an X50 eye tracker (Tobii Technology, Sweden). The eye tracker is noncontact and provides data on (i) eye position in 3D space, and (ii) the point of gaze. This allows the screen position of “test stimuli” to be calculated, and eye gaze responses to the “test stimuli” to be assessed in “real time”. A software algorithm was developed to determine if “test stimuli” have been perceived based on the direction, amplitude and latency of a subject’s gaze response. A feasibility study was conducted with 29 subjects comprising 4 groups: (i) healthy adults, (ii) healthy children, (iii) adult patients with visual field defects, and (iv) child patients with visual field defects. Subjects performed SVOP tests which replicated the Humphrey Field Analyser (HFA) C-40 screening test with a stimulus size of Goldmann III and intensity of 14dB. Subjects able to do so also performed equivalent HFA C-40 tests for comparison. In healthy subjects 99.1% of SVOP test points were in agreement with a healthy visual field. In patients with visual field defects, 89.8% of test points were in agreement with HFA equivalent tests. The visual field defects identified using SVOP in the child patients were consistent with their clinical findings. A clinical evaluation of SVOP was undertaken in the second stage of this research with 122 subjects comprising the same four subject groups as in the feasibility trial. An “ideal” test protocol resulted in 8 uniocular visual field tests for each subject comprising 4 SVOP tests and 4 HFA tests. In children where uniocular testing was not tolerable, two binocular SVOP tests were performed. The sensitivity and specificity of the SVOP tests were computed using a direct comparison with reliable HFA tests, and repeatability of SVOP and HFA tests were assessed using Cohen’s kappa coefficient. In child patients unable to provide a reliable HFA test, their clinical history, other clinical findings and the repeatability of their SVOP tests were used to assess the SVOP results. The overall sensitivity and specificity of the SVOP testing was 72.7% and 96.8% respectively. The sensitivity had a greater variation than the specificity amongst the different subject groups. The repeatability of SVOP tests was slightly reduced as compared to the HFA tests across all groups with kappa coefficient’s of 0.65 and 0.74 for SVOP and HFA respectively. In child patients without reliable HFA equivalent tests the SVOP results could commonly be associated with other clinical findings and repeatable testing added to the confidence in the reliability of these cases. The developed SVOP technique performs well with accurate eye tracking data and an attentive child. It has proved extremely useful in identifying and monitoring visual field defects in several child patients who required regular visual field assessment.

Previous research into everyday conception of personal relationships has been sparse and fragmented, and the various specialisms fail to deal with the broader issue of interpersonal understanding. Following review of the research and theoretical background, with particular reference to changing paradigms, a holistic approach is proposed for an exploration linking the content of explanation and reflection about relationships with the incidence of conceptualising. The methodology, employing content analysis, illustrative studies and a musical analogue, is outlined. Initially focusing on verbalised conception in the form of accounts, a procedure of 'simulated correspondence with a confidant' was employed to facilitate unrestricted disclosures in general descriptions of relationships. Three coding schemes were devised for content analysis of accounts (and for independent use in subsequent research). These pertained to: (1) specific concepts and themes; (2) explanation of interpersonal effect and significance; and (3) intersubjectivity in accounts. Overall indications from the content analyses are that accounts are characterised by superficiality of detail and insight, and concentrate more on basic viability, and on social and visible aspects of personal relationships than on intimate and psychological aspects. The limitations of content analysis, and the deficiencies disclosed, suggest attention should be given to omission in content as much as inclusion, and also to the prior issues of motivation and the extent of relationship "mindfulness". A musical analogy (with particular reference to representation, knowledge and appreciation) is employed to advance the exploration beyond the linguistic aspects of conception to a more general model of relationship awareness. A second set of studies turn to (1) the frequency and occasioning of reflection on relationships; (2) reappraisal over time; (3) interest in relationships compared with other subjects of general interest; and (4) factors which disincline conscious relationship deliberation and analysis. There are indications throughout of a sex difference, with men as less reflective, less inclined to participate in providing accounts, and less interested in personal relationships. Disincentives are suggested, and a theory of 'relationship mindlessness' is discussed, connecting impoverishment of content and incidence with the late emergence of 'personal relationships' as a subject of formal scholarly enquiry in psychology. It is proposed that such mindlessness, and associated disincentives, are implicated in relationship problems, and that extension of relationship education, knowledge and interest are indicated. The practicalities and possible form of learning about relationships and consciousness-raising were explored in a trial relationship understanding course. Counter-indicat ions for such consciousness-raising were evaluated by analogy with music appreciation.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [81]-115).