bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dimensional characteristics of the optic nerve head and peripapillary crescents in myopia
Authors: Rudnicka Alicja R. 
Published: July 2002

Purpose: To establish typical normal values for the optic disc area (DA), neuroretinal rim area (NRA), cup area (CA) and peripapillary crescent area (PCA) over a wide range of ametropia, and to investigate whether any of these optic disc parameters are related to axial length and/or ocular refraction.Method: The sample comprised 122 normal subjects, aged 18.5 to 35.4 years, free from any ocular or systemic disease, with refractive errors ranging from +4.00 D to −25.75 D. Subjects were divided into four groups; (1) non‐myopic controls; (2) myopes without peripapillary crescents; (3) myopes with small peripapillary crescents; and (4) myopes with larger crescents, having a CA at least 40% of the DA. All subjects underwent the following: corneal front surface keratometry, A‐scan ultrasonography, cycloplegic refraction and fundus photography with the Carl Zeiss Jena camera using Kodak Ektachrome colour‐slide film.A CCD camera linked to a computer was used to digitise the fundus slides. Optic disc features were delineated by computer‐assisted techniques. Using a ray‐tracing method (Bennett et al., 1994) and knowledge of the fundus camera magnification (Rudnicka et al., 1992), the true dimensions of the optic disc parameters could be determined.Results: In group 1, DA ranged from 1.36 to 2.88 mm2; in group 2, from 1.30 to 2.79 mm2; in group 3, from 1.50 to 5.04 mm2, and in group 4, from 1.21 to 9.22 mm2. Groups 1, 2 and 3 did not differ significantly from each other for any optic disc parameter (values for the other optic disc parameters will be presented). DA and NRA are significantly larger in group 4 than in the other three groups. Cup area did not differ significantly between the groups. DA, NRA and PCA increase with axial length elongation and increasing myopia in groups 3 and 4 only.Conclusions: Knowledge of the dimensions of the optic nerve head and peripapillary crescents may aid in the diagnosis of pathologically disturbed optic discs.
The evolving interface between ophthalmology and optometry
Authors: McLeod David 
Published: July 2002

Ophthalmologists and optometrists have a similar mission: the provision of high‐quality, cost‐effective ophthalmic healthcare to the population whom they serve. Each profession's respective focus of special expertise provides the basis for traditional pathways of patient referral, e.g. from optometrist to ophthalmologist (where surgery, such as that for cataract, will bestow most benefit) or from opthalmologist to optometrist (where low vision aids are the patient's only respite from degenerative macular disease). This interface (or common boundary) between these two ophthalmic specialties at the point of patient referral thus represents ‘an opportunity for positive interaction’. In the past, there was also evidence of that interface representing ‘a state of mutual interdependence’, whereby optometry undertook opportunistic population screening (or case finding) and provided a primary source of help for general practitioners (given the gross inadequacies of the HES), while ophthalmology constituted a major provider (after providence's bounty of myopia and presbyopia) of much good business by way of correction of aphakia. But waiting list initiatives, lens implants and refractive surgery threaten to change all that.Furthermore, the vacuum in eye care left by patients' primary healthcare providers, through their general practitioners' lack of confidence and competence in all matters ophthalmological, has created a basis for potential conflict between the professions‐‐a ‘negative interface’ of antagonism, if not hostility‐‐when considering community ophthalmology. Thus, as the NHS (and with it the HES) becomes progressively more commercialised and fragmented (‘much like the GOS’, some would say), will patients' best interests be served by interprofessional rivalry (with the potential to bring out the worst in College rhetoric and obfuscation) and by naked commercial competition instigated by healthcare commissioners? Is ‘shared care between HES and GOS’ a non‐starter, or do other areas of mutual interdependence‐‐especially research and teaching‐‐provide opportunities to bypass undesirable obstructions to sensible debate and the realisation of each profession's reasonable aspirations?
Clinical and specular micrographic findings in corneal guttata and Fuchs' corneal endothelial dystrophy
Authors: Jackson A. J. , Frazer D. G. , Robinson F. O. , Barnett S. 
Published: July 2002

Focal excrescenses of altered basement membrane material, known as corneal guttata, are a common occurrence in the elderly. A small proportion of those who develop this condition exhibit signs of corneal endothelial dysfunction and progress to Fuchs' corneal endothelial dystrophy. The relationship between the distribution and relative density of guttata and the morphological appearance of the corneal endothelium is as yet poorly understood.In this study, 40 eyes of 20 caucasian patients (5 male and 15 female) identified as having central corneal endothelial guttata were examined (mean age 76 years). Ten eyes noted as having a previous history of ocular trauma, surgery or anterior segment inflammation were excluded from the study. Clinical and specular micrographic findings are compared.Clinical examination confirmed that guttata were most densely distributed in the central cornea. Examination of all four mid‐peripheral quadrants identified the superior cornea as being least severely affected in the majority of cases. In 26 of the 30 eyes examined there was evidence of pigmentary dusting of the corneal endothelium. The severity of guttata did not appear to correlate with the density or distribution of the pigment. In cases of moderate to advanced disease, where guttata had become confluent and thus obscured the view of the corneal endothelium, the clinical differentiation of pigment, guttata and diffuse scarring became difficult. Specular microscopy confirmed the accuracy of the clinical five‐point scale used to quantify the distribution and density of guttata in the study. Quantitative analysis of corneal endothelial cells from the mid‐peripheral cornea indicated that the severity of guttata did not necessarily correlate with a reduced cell count. Central cell counts proved elusive as reflections from the irregular surface created by confluent guttata failed to produce specular images of the underlying endothelium.The authors conclude that the specular microscope is a useful diagnostic tool in the differentiation of guttata from other abnormalities of the endothelium and Descemet's membrane. Specular micrographic imaging also enables the examiner to quantify the distribution and density of guttata. The relationship between the severity of corneal guttata, endothelial cell counts and pigmentation is not well defined and further study of the progression of the disease process is required.
Infant hyperopes: (a) detection by video‐refraction and (b) longitudinal changes
Authors: Ehrlich D. L. , Anker S. , Atkinson J. , Braddick O. J. , Weeks F. , Wade J. 
Published: July 2002

Non‐cycloplegic video‐refraction and cycloplegic retinoscopy refraction results are reported for a Cambridge population of binocular, non‐strabismic infants aged 7–9 months.Method: The Cambridge vision screening programme detected high refractive errors by measuring the accommodative response to a 75 cm distance toy using the VPR‐1 video‐refractor. Of 4452 infants screened, the binocular mean refraction was −0.7 D, i.e. +0.62 D accommodative ‘lag’ or focus error (SD = ± 0.92 D). Seven percent had + 1.5 D refraction, i.e. + 2.8 D focus error or accommodative ‘lag’ in any one meridian. Of those followed up, refraction was also measured by cycloplegic retinoscopy (cycloRet) and VPR‐1 (cyclo VPR) after 1 drop 1% cyclopentolate.Results: Of the 223 infants who had large lags of accommodation + 2.8 D: (a) High hyperopia of + 3.5 D in any one meridian, by cyclo‐Ret, was found in 173/223 (78%) of these infants. The mean cyclo‐Ret spherical equivalent was + 3.8 ± 1.8 DS and unsigned astigmatism 0.8 ± 0.7 DC. The magnitude of the largest accommodative lag was significantly related to the cyclo‐Ret most‐positive‐meridional power (r = 0.4, P < 0.0001, n = 223). The majority orientation of the largest (non‐cyclo‐VPR) lag power was horizontal (WTR astigmatism). (b) The latest longitudinal refractive changes in this highly hyperopic group and also a control group will be described in terms of mean spherical equivalent, astigmatism and anisometropia.Conclusion: The large lags of accommodation can reveal infants with highly hyperopic meridians. These infants may require early partial spectacle correction.Acknowledgement: Supported by the Medical Research Council (Grant G7908507).
Vision training for children with specific learning difficulties (dyslexia)
Authors: Grounds Annette 
Published: July 2002

Research has shown that up to 70% of dyslexic individuals have a defect of the transient visual system (a magnocellular defect) (Lovegrove et al., 1986). Clinically, the results presented have confirmed this but suggest an even higher percentage. Fortunately, these magnocellular defects can be improved or essentially eliminated with appropriate treatment and this results in a significant improvement in school work.A combination of vision therapy and specific lenses and/or prisms are used in the clinic, plus the use of coloured overlays or tinted spectacles. Clinical results have shown that vision training is the major cause of improving or eliminating the transient defect (see below). Also, specific near vision spectacles with lenses and/or prisms which stabilize print are at least as successful, if not more so, at giving immediate relief from visual discomfort while reading, as coloured overlays or tinted spectacles. Further, it is postulated that the colour chosen may be related to the severity of the magnocellular defect (the most severe choosing an overlay in the short wavelength). The possible reasons for this will be presented. It has also been found that the favoured colour changes during the vision therapy and indeed with or without specific near spectacles.Following improvement with treatment of the magnocellular defect up to 73% reported significant improvement with school work and over 54% of these showed marked improvement.The results of the vision therapy treatment of some 200 youngsters are presented along with detailed analysis of an extensive questionnaire, completed prior to the first attendance. These indicate the main factors which are linked with dyslexia and the major problems complained of.Following successful treatment, apart from habitually worn spectacles, nothing further should subsequently be required.
Study into the efficacy of a refractive multifocal intraocular lens implant
Authors: Kotecha A. 
Published: July 2002

In the last decade there has been a significant advance in the types and materials of intraocular lens implants available. Recently, there has been a trend towards developing a multifocal intraocular lens (IOL) implant and, with advances in surgical techniques, there is the possibility of abolishing the need for postoperative spectacle correction completely. For the last seven years at the Croydon Eye Unit we have been involved in four multicentre clinical trials into the efficacy of the bizonal refractive form of multifocal IOL design. The results presented focus on the IOLAB 8191M multifocal implant, with a near central zone of 1.5 mm diameter, and a +4.00 D addition. When implanted, this is equivalent to a spectacle addition of +2.80 D.The surgical technique used was phacoemulsification with capsularrhexis, but incision size had to be increased to 6.0 mm in order to insert the IOL. However, postoperative corneal astigmatism was still well controlled, and this returned to preoperative values in 82% patients within 5 weeks. From previous studies we found that patients with a preoperative corneal astigmatism of <1.00 D performed significantly better postoperatively (study inclusion criteria specific <2.00 D of corneal astigmatism for patient qualification). To data, 245 8191M multifocals have been implanted in Europe, 228 of which have had a minimum of 3 months follow‐up. At our centre, 47 eyes have been implanted with the 8191M, 85% of whom have had at least a 12 month postoperative follow‐up.Our results have shown 64% patients achieving unaided visions of 6/12 or better for distance, and 84% J3 or better for near. In 45 eyes, acuity measurements with the distance correction in place indicates that 100% of eyes achieved 6/12 or better for distance, and 96% J3 or better for near. The effects of glare, tested with the Brightness Acuity Tester (BAT), showed no significant detrimental effect on visual acuity, and this was also shown to be independent of pupil size.In summary, the refractive design of multifocal IOL has been shown to give successful visual results. However, in order to achieve excellent results from multifocal designs of IOL, it is essential to have an astigmatically neutral form of surgery and accurate biometry.
A view of visual adaptation from a different position
Authors: Whitaker D. , McGraw P. V. , Levi D. M. 
Published: July 2002

Purpose: To examine the effect of adaptation upon perceived visual location of luminance‐defined and texture‐defined stimuli.Methods: We describe an illusion in which 5 sec of adaptation to an antisymmetric Gaussian stimulus results in a marked perceived misalignment in a subsequently‐viewed 3‐Gaussian blob stimulus. The magnitude of perceived misalignment was established for various levels of adapting and test contrast.Results: The effect of varying the contrast of the adapting and test stimuli depends only upon the ratio of adapting/test contrast. Adaptation effects for luminance‐ and texture‐defined stimuli differ in terms of inter‐ocular transfer and rate of decay. Whilst adapting and testing to the same type of stimulus (luminance‐ or texture‐defined) produces large shifts in perceived position, little or no crossover was found. The data are accounted for by a model in which the centroid of the linear combination of after‐image and test stimulus is extracted.Conclusion: The perceived location of both luminance‐ and texture‐defined stimuli can be strongly influenced by appropriate adapting stimuli. However, the adaptation processes for both types of stimuli remain independent and demonstrate different characteristics.
Predicting successful outcomes in the low vision management of elderly people
Authors: Hill A. R. , Cotton L. J. 
Published: July 2002

Structured interviews were conducted with 195 visually impaired people, aged 65 or over.A factor analysis was employed to organise the data and nine factors emerged. These were: satisfaction with the service, vision, general health, psycho‐social measures, hearing impairment, hardiness, finance, religious beliefs and reported time since vision loss.Subsequent analysis, including discriminate analysis, showed that four measures could be used for assessing low vision service outcome. These were:1. A measure of patient satisfaction.2. A function measure which assesses improvement in various daily activities.3. Measures of the impact of the service on personal well being.4. A measure assessing a patient's understanding of their eye condition.These findings will be discussed.
Impact of Pediatric Epilepsy on the Family: A New Scale for Clinical and Research Use
Authors: Camfield Carol , Breau Lynn , Camfield Peter 
Published: July 2002

Summary:  Purpose: There is no brief, global instrument available that specifically measures the psychosocial impact of pediatric epilepsy on the family. An 11‐item scale was created for parents' use to evaluate the influence of epilepsy on the major aspects of their family and child's life. This will be a helpful tool both in the clinical setting and as an outcome measure for research studies.Methods: Mothers rated their child's quality of life on a visual analogue scale (1–6) and completed the Impact of Pediatric Epilepsy Scale (IPES), which assesses the impact on academic achievement, participation in activities, health, relationships with family and with peers and siblings, social activities, self‐esteem, and the caregiver's hopes for their child's future adapted from the scale developed by Jacoby. External validation was determined by comparison of the IPES with physicians' reports of the characteristics of the child's epilepsy and neurological limitations and parents' ratings on the Family Environment Scale or Parenting Stress Index. In addition, each school‐aged child completed the Piers‐Harris Children's Self‐Concept Scale, Brother‐Sister Questionnaire, and Loneliness Scale. Teachers of children completed the Academic Performance Rating Scale. Seven days later, retest reliability of the IPES was evaluated.Results: Ninety‐seven mothers of children aged 2–16 years completed the IPES and the appropriate family and age‐related questionnaires. Internal validation on the IPES yielded a Cronbach's a for the scale of 0.92. A significant Pearson's correlation indicated that total scores were consistent over time (r = 0.81). Spearman's correlations for the individual items were also significant, ranging from 0.48 to 0.78. Significant Spearman's correlations also indicated that quality of life was negatively related to impact on each of the 11 items of psychosocial function. Children with IPES scores above the median differed in some psychosocial aspects from those who scored below. Their parents were more stressed, their siblings were more respectful, they had lower self‐esteem, and they experienced more emotional problems. Total impact was also significantly related to seizure frequency, total number of medications taken, number of visits to a physician in the previous year, and number of nights spent in hospital for neurological reasons.Conclusions: The IPES is an accurate, acceptable, and quick measurement tool that reflects the way in which childhood epilepsy has an impact on the child and on family life. It may be helpful in routine clinical care and may be useful in the research setting to find ways to improve the lives of children with epilepsy.
Ecology of the Pteridophytes on the Southern Slopes of Mt. Kilimanjaro. Part II: Habitat Selection
Authors: Hemp A. 
Published: July 2002

Abstract: Based on the evalutation of 957 vegetation plots on the southern slope of Mt. Kilimanjaro, habitat preferences for 140 species of pteridophytes were evaluated. Using the average percentage cover value, and taking into account the pteridophyte flora's composition, life form spectra and its spectra of seasonal growth pattern, eight vegetation formations were recognized. Ferns contributed less than 1 % of the vegetation cover of salt marshes, ruderal vegetation, grasslands and (sub‐)alpine heathlands. In contrast, pteridophytes constituted the most important vascular plant group on rocks, where 64 species were found, forming about two‐thirds of the vegetation cover. With respect to alpha and beta diversity and fern biomass, luxuriant montane forest was the main habitat for pteridophytes on Mt. Kilimanjaro. Here 130 pteridophyte species (93 % of the whole pteridophyte flora of the study area), on average, contributed 16 % of the total vegetation cover. Epiphytic ferns, tree ferns and filmy ferns had their main distribution between 1900 and 2400 m, in a zone coinciding with the maximum rainfall on Mt. Kilimanjaro's southern slope.Poikilohydrous species were typical of dry habitats, such as on rocks, in meadows or along roadsides, but they also occurred in the often sun‐exposed epiphyte layer in moist montane forests. Deciduous species, which were in many cases fire resistant, had a similar distribution; however, inside the forest belt they were restricted to the lower and upper parts, where fires are a common phenomenon. Evergreen species were the dominant group in swamps, forests and forest clearings.Compared to other volcanoes in East Africa, Mt. Kilimanjaro is distinctly richer in fern species in general and in filmy ferns, tree ferns and epiphytic ferns in particular, suggesting that the forest belt of the southern slope of Mt. Kilimanjaro is wetter than those of other high mountains in East Africa.
Plastic Josephson junctions
Authors: Schön Jan Hendrik 
Published: July 2002

The electrical properties of polythiophene thin films can be varied from insulating to superconducting using the field effect. A spatial modulation of the properties can be achieved by patterning of the gate electrode leading to the preparation of Josephson junctions based on solution cast polymer films. These junctions can be used to build a polymer superconducting quantum interference device or to study the superconducting properties of the material itself. The observations are in accordance with the idea of electron–phonon-mediated superconductivity in this organic polymer.
At the request of the authors and editor, this article is being retracted effective 24 February 2003.
Nanoscale organic transistors based on self-assembled monolayers
Authors: Schön J. H. , Bao Z. 
Published: July 2002

A device structure is reported for the fabrication of nanoscale organic transistors. In this structure, a self-assembled monolayer is used to define the channel length, as well as acting as the semiconducting material. High current modulation and high current output are demonstrated with 4,4′-dithiolbiphenylene. Various dielectric materials, such as SiO2,Al2O3, and a self-assembled silane monolayer, have been shown to result in high-performance transistors. Finally, nanopatterning can also be achieved by using an insulating alkanethiol to define the channel length of a conventional organic field-effect transistor.
At the request of the authors, this article is being retracted effective 24 February 2003.
Comparison of ensemble and single molecule approaches to probing polymer relaxation dynamics near Tg
Authors: Deschenes Laura A. , Vanden Bout David A. 
Published: July 2002

Single molecule spectroscopy and polarization holeburning (PHB) are used to measure the dynamics of rotation for rhodamine 6G in poly(methylacrylate). It is found that the ensemble average correlation time obtained from the single molecule experiments is the same as that obtained from bulk fluorescence anisotropy decay. Both reflect the same underlying dynamics as the mechanically measured α relaxation. Fitting α relaxation and PHB data to the Vogel–Tammann–Fulcher (VTF) equation, it is found that the two measurements follow the same temperature dependence, but with absolute times that differ by nearly four orders of magnitude. This difference is discussed in two contexts. In the first the relative ratio of the correlation and α-relaxation times depend on probe size, in which case the large difference is not unexpected given the size of the probe. In the second, the difference is attributed to specific probe/polymer interactions. In this case, a modified VTF equation that includes an activation energy term can be used to explain this phenomenon; when all parameters but the activation energy are fixed to the α-relaxation values, it is found that an activation energy of 21 KJ/mol could cause the observed slowing of the rhodamine 6G rotational correlation times.
At the request of the authors and editor, this article is being retracted 27 April 2006.