bluuebunny/crossref_metadata_2025 huggingface dataset:
PERAN KEPALA SEKOLAH DALAM MENOLONG GURU MEMILIKI SIKAP DISIPLIN WAKTU DI SEKOLAH KRISTEN DI LUBUKLINGGAU
Authors: Kanaf Katrin Agustina
Published: October 2022

Disiplin waktu merupakan salah satu ketertiban yang perlu diterapkan di sekolah. Sebagai pemimpin di sekolah, Kepala sekolah menjalankan perannya dalam menolong guru memiliki sikap disiplin waktu di sekolah. Penelitian ini bertujuan untuk mendeskripsikan peran kepala sekolah dalam menolong guru memiliki sikap disiplin waktu pada sebuah sekolah di Sumatera Selatan. Metode kualitatif deskriptif dengan observasi dan wawancara sebagai teknik pengumpulan data diterapkan dalam studi ini. Data yang terkumpul kemudian dianalisis menggunakan tahap reduksi data, penyajian data dan penarikan kesimpulan. Hasil penelitian menunjukkan kepala sekolah sangat berperan penting di sekolah. Kepala sekolah menjalankan perannya sebagai educator, supervisor dan leader dalam menolong guru memiliki disiplin waktu dengan cara membuat strategi yang dapat melatih gurunya untuk disiplin waktu. Kepala sekolah memberikan teladan disiplin waktu terlebih dahulu sebelum menolong gurunya. Kepala Sekolah Kristen di Sumatera Selatan telah menjalankan peran ini dalam menolong gurunya memiliki sikap disiplin waktu. Peran kepala sekolah sangat penting dalam menolong guru memiliki sikap disiplin waktu.
PERAN GURU KRISTEN DALAM MENERAPKAN DISIPLIN ASERTIF UNTUK MENOLONG MURID KELAS IV YANG KECANDUAN GAWAI
Authors: Mindarintia Leny , Yoedo Yuli Christiana
Published: October 2022

Guru Kristen memiliki peran dalam menolong murid kelas IV yang kecanduan gawai. Penelitian ini bertujuan untuk menjelaskan peran guru tersebut dalam menggunakan metode disiplin asertif. Peran guru yang digunakan adalah sebagai pendidik karakter, pelayan, gembala, dan pemegang otoritas di dalam kelas. Penelitian ini menggunakan metode kualitatif dengan wali kelas sebagai subyek penelitian dan keempat murid berserta orang tuanya sebagai informan. Observasi dalam penelitian ini dilakukan selama kurang lebih tiga bulan, kemudian peneliti melakukan wawancara dengan subyek penelitian dan mengonfirmasi data dengan informan. Peneliti menggunakan teori disiplin asertif, prinsip guru Kristen dalam mendisiplin murid, dan kecanduan gawai yang diintegrasikan dengan Iman Kristen untuk mengolah data yang ditemukan. Berdasarkan hasil analisis, peneliti menemukan bahwa peran guru Kristen dalam menggunakan metode disiplin asertif tidak dapat menolong murid yang kecanduan gawai. Guru Kristen dapat menggunakan metode lainnya seperti konseling keluarga. Guru Kristen juga dapat mempertimbangkan tingkat kecanduan dan latar belakang pendidikan keluarga murid untuk memilih metode yang tepat. Dengan demikian, guru Kristen dapat menolong murid yang kecanduan gawai dengan lebih efektif.
Voltage‐gated K+ currents of mouse dendritic cells
Authors: Fischer Hans-Georg , Eder Claudia
Published: July 2002

Dendritic cells (DC) were enriched from murine spleen by exploiting their intermediate density and transient weak adherence. The isolated population contained excellent antigen presenting cells with high surface expression of major histocompatibility complex (MHC) class II determinants thus exhibiting crucial immunofunctional characteristics of DC. Cells of typical dendritic shape were electrophysiologically analysed using the whole cell configuration of the patch clamp technique. All 26 cells expressed only outward K+ currents comparable to those detected in cytokine‐activated microglia. Co‐purified splenic macrophages, in contrast, displayed an inward rectifying K+ current.
Establishment of the apical‐basal axis in multicellular plant embryos
Authors: Berger Frédéric , Brownlee Colin
Published: July 2002

Summry— Apical‐basal polarity of multicellular plant embryos is defined originally in the zygote before the first cell division and the apical and basal daughter cells follow distinct developmental programs. Mechanisms controlling these initial embryonic steps are still poorly understood but advances both in the flowering plant Arabidopsis and the alga Fucus have lead to various models and hypotheses. These point to the positional information as a major source for patterning the early embryo. Hypotheses concerning the possible location of this positional information are reviewed and discussed.
Substrate recognition and fidelity of strand joining by an archaeal DNA ligase
Authors: Nakatani Masaru , Ezaki Satoshi , Atomi Haruyuki , Imanaka Tadayuki
Published: July 2002

We have previously identified a DNA ligase (LigTk) from a hyperthermophilic archaeon, Thermococcus kodakaraensis KOD1. The enzyme is the only characterized␣ATP‐dependent DNA ligase from a hyperthermophile, and allows the analysis of enzymatic DNA ligation reactions at temperatures above the melting point of the substrates. Here we have focused on the interactions of LigTk with various DNA substrates, and its specificities toward metal cations. LigTk could utilize Mg2+, Mn2+, Sr2+ and Ca2+ as a metal cation, but not Co2+, Zn2+, Ni2+, or Cu2+. The enzyme displayed typical Michaelis–Menten steady‐state kinetics with an apparent Km of 1.4 µm for nicked DNA. The kcat value of the enzyme was 0.11·s−1. Using various 3′ hydroxyl group donors (L‐DNA) and 5′ phosphate group donors (R‐DNA), we could detect ligation products as short as 16 nucleotides, the products of 7 + 9 nucleotide or 8 + 8 nucleotide combinations at 40 °C. An elevation in temperature led to a decrease in reaction efficiency when short oligonucleotides were used, suggesting that the formation of a nicked, double‐stranded DNA substrate preceded enzyme‐substrate recognition. LigTk was not inhibited by the addition of excess duplex DNA, implying that the enzyme did not bind strongly to the double‐stranded ligation product after nick‐sealing. In terms of reaction fidelity, LigTk was found to ligate various substrates with mismatched base‐pairing at the 5′ end of the nick, but did not show activity towards the 3′ mismatched substrates. LigTk could not seal substrates with a 1‐nucleotide or 2‐nucleotide gap. Small amounts of ligation products were detected with DNA substrates containing a single nucleotide insertion, relatively more with the 5′ insertions. The results revealed the importance of proper base‐pairing at the 3′ hydroxyl side of the nick for the ligation reaction by LigTk.
Preceding chemotherapy, tumour load and age influence engraftment in multiple myeloma patients mobilized with granulocyte colony‐stimulating factor alone
Authors: Desikan K. R. , Tricot G. , Munshi N. C. , Anaissie E. , Spoon D. , Fassas A. , Toor A. , Zangari M. , Badros A. , Morris C. , Vesole D. H. , Siegel D. , Jagannath S. , Barlogie B.
Published: July 2002

Haematopoietic growth factors, especially granulocyte colony‐stimulating factor (G‐CSF), are frequently utilized alone for peripheral blood stem cell (PBSC) procurement to avoid the morbidity associated with high‐dose chemotherapy (HDT). Moreover, the cytotoxic agents used may not be the most optimal therapy for the malignancy. It also makes scheduling of apheresis easier. Factors having an impact on PBSC procurement and engraftment after HDT were analysed in 117 multiple myeloma patients mobilized with G‐CSF (10–16 µg/kg, median 12 µg/kg) alone using Cox regression analysis. A median of 6·2 × 106 CD34 cells/kg (range 0·6–34·1) were procured during leukapheresis and a median of 2·5 × 106 CD34 cells was infused after the first HDT (range 0·3–23·9). The only factor significantly affecting optimal PBSC procurement was duration of preceding conventional chemotherapy (P = 0·002). Granulocyte recovery was prompt in almost all patients, 75% of whom attained a granulocyte count of 0·5 × 109/l by day 13 (median 11, range 7–19). However, platelet recovery to both 20 × 109/l (median 12 d, range 8–50+) and 50 × 109/l (median 20 d, range 7–205+) varied widely. On univariate analysis, factors influencing platelet recovery were the number of CD34 cells/kg infused, age, β2‐microglobulin levels, response to preceding therapy, bone marrow plasmacytosis and duration of prior therapy. Factors attaining significance on multivariate analysis included number of CD34 cells/kg infused (P = 0·007), β2‐microglobulin levels (P = 0·0001), most probably representing disease load, and age (P = 0·002). Patients with high tumour burden, i.e. β2‐microglobulin levels > 2·5 mg/l, probably benefit from chemotherapy for mobilization both in terms of cytoreduction and adequate stem cell mobilization resulting in accelerated engraftment.
Diffuse large B‐cell non‐Hodgkin's lymphoma in a patient with autoimmune lymphoproliferative syndrome
Authors: Boulanger Emmanuelle , Rieux‐Laucat Frédéric , Picard Capucine , Legall Marie , Sigaux François , Clauvel Jean‐Pierre , Oksenhendler Eric , Le Deist Françoise , Meignin Véronique
Published: July 2002

Mutations of Fas or Fas ligand genes result in the autoimmune lymphoproliferative syndrome (ALPS) in humans. We report here a diffuse large B‐cell non‐Hodgkin's lymphoma occurring in a man with ALPS. Fas‐mediated lymphocyte apoptosis was defective in vitro, owing to a mutation within the death domain of the Fas molecule. High‐dose methotrexate and doxorubicin–based chemotherapy led to complete remission of lymphoma.
Ovicidal and larvicidal effectiveness of several insect growth inhibitors and regulators on the codling moth Cydia pomonella L. (Lep., Tortricidae)
Authors: Charmillot  , Gourmelon  , Fabre  , Pasquier
Published: July 2002

Several insect growth inhibitors (IGIs) and regulators (IGRs) were tested in the laboratory for their ovicidal and larvicidal properties on the codling moth C. pomonella, by dipping apples in solutions of them. The IGIs which block chitin synthesis – diflubenzuron, hexaflumuron and teflubenzuron – were noticeably more effective against eggs than on newborn larvae with preventive ovicidal 50% lethality concentrations (LC50) values of approximately 0.6, 1.3 and 15 p.p.m., respectively, and larvicidal LC50 values of 104, 1208 and 204 p.p.m. Flufenoxuron, on the other hand, is almost as effective on larvae (LC50 : 9.9 p.p.m.) as on eggs (LC50 : 5.4 p.p.m.). Fenoxycarb, an IGR juvenile hormone analogue, acts as an excellent ovicidal product with an LC50 value of 0.05 p.p.m. Tebufenozide, an IGR ecdyson (moulting hormone) agonist, is exclusively larvicidal with an LC50 at 0.4 p.p.m. Methoxyfenozide, an IGR of the same family and currently being developed, acts as effectively on eggs as on larvae with ovicidal and larvicidal LC50 values of about 0.6 and 0.8 p.p.m., respectively. When ovicidal products are applied as a curative treatment on eggs less than 24 h old, their effectiveness is much lower than that obtained from preventive application.
n‐3 polyunsaturated fatty acid supplementation, monocyte adhesion molecule expression and pro‐inflammatory mediators in Type 2 diabetes mellitus
Authors: Sampson M. J. , Davies I. R. , Brown J. C. , Morgan V. , Richardson T. , James A. J. , Sampson A. P. , Hughes D. A.
Published: July 2002

SUMMARY

Aims  To examine the effect of n‐3 polyunsaturated fatty acid supplements on the monocyte surface expression of adhesion molecules involved in pro‐atherogenic monocyte–endothelial interactions, and on pro‐inflammatory mediators in Type 2 diabetes mellitus.

Methods  Twenty‐nine subjects with Type 2 diabetes and 21 controls without diabetes were studied. Monocyte expression of leucocyte function‐associated antigens 1 and 3, intercellular adhesion molecule‐1, and the major histocompatibility complex class II molecule HLA‐DR were measured using a laser flow cytometric method. Supplementation with 2.08 g n‐3 fatty acids for 21 days was undertaken and measurements repeated. Plasma soluble adhesion molecule concentrations, plasminogen activator inhibitor‐1 activity and antigen and pro‐inflammatory mediators (cysteinyl leukotriene and monocyte leukotriene B4) were also measured.

Results  Groups did not differ in monocyte expression of adhesion molecules or HLA‐DR, or in leukotriene production although plasma soluble adhesion molecule concentrations were higher in the diabetes groups (P < 0.05). n‐3 fatty acid supplementation influenced neither the expression of these molecules nor plasma soluble adhesion molecule concentrations or leukotriene production.

Conclusions  This study does not support increased monocyte adhesion molecule expression or abnormal monocyte production of pro‐inflammatory mediators as mechanisms for increased atherogenic risk in Type 2 diabetes. Cardioprotective actions of n‐3 fatty acids may not be mediated through these mechanisms.
Blur due to pupil area when using progressive addition spectacles
Authors: Burns David
Published: July 2002

The progression zone of a progressive addition spectacle lens cannot provide a sharp retinal image as it presents the pupil with a range of powers through which to view an object. The resulting blur is explored mathematically. The nature of this blur is extraordinary but its visual significance is very slight and is less than previously believed. Peripheral astigmatism, found in all such lenses, may lower their visual performance.
Estimation of back vertex power and magnification of variable focus telescopes
Authors: Woo George C. , Cheng‐wan Lu , Wessel John A.
Published: July 2002

Formulae and methods have been developed to estimate the back vertex power and the effective magnification of the variable focus telescopes according to the change of the telescope length.
A novel approach to measuring the wettability of rigid contact lenses. Mass measurement of the adherent liquid on the rigid lens surface (1)
Authors: Shirafkan Abbas , Woodward E. Geoffrey , Hull Christopher C.
Published: July 2002

A novel approach and the equilibrium sessile drop (laser assisted) method were used to determine the wettability of hydrated and unhydrated PMMA, Polycon II, Boston IV, Equalens and Boston RXD rigid contact lens materials. In the new method the ability of the contact lens surface to attract the liquid is evaluated by measuring the adhered mass of liquid on the front lens surface. The mass has a direct relationship to contact lens wettability, so the greater the lens surface hydrophilicity the more liquid adheres to the contact lens surface. In the hydrated state, Equalens and Boston IV showed the greatest hydrophilicity of all five materials, although there was no significant difference between them (P > 0.9). Boston RXD had a lower ability to attract liquid and there was a significant difference between it and the next higher material which was Boston IV (P < 0.005) and also the next lowest Polycon II (P < 0.00001). PMMA had the lowest capability to adhere liquid and there was a significant difference between PMMA and Polycon II (P < 0.00001). The new method is simple and quick to use and gives greater discrimination and repeatability than other current methods.
A new protocol for the optometric management of patients with reading difficulties
Authors: Lightstone A. , Evans B. J. W.
Published: July 2002

Research by Evans et al. (Ophthal. Physiol. Opt.15, 481–487, 19956) has demonstrated a correlation between visual processing and ocular motor factors in people with specific reading difficulties (dyslexia). In addition, research by Wilkins et al. (Ophthal. Physiol. Opt.14, 365–370, 1994) has shown that some people with dyslexia will benefit from a reduction of perceptual symptoms of discomfort and distortion if they use individually prescribed coloured filters. Three examples of the dyslexic patients who attend at the Institute of Optometry clearly demonstrate the importance of full investigation of ocular function, including the assessment of the effect of colour on visual perception. All three patients presented with similar symptoms of asthenopia when reading. Symptoms were alleviated for the first patient by use of orthoptic treatment of an exotropia with intermittent suppression. With the second patient, ocular motor functions were found to be within acceptable limits and relief of symptoms was obtained by the prescribing of lenses of a specific chromaticity. For the third patient, both orthoptic intervention and the use of specifically tinted lenses were necessary to relieve the visual difficulties that were being experienced. By taking advantage of recent research and developments in optometric instrumentation, it is possible for some of those with dyslexia to receive considerable benefit from optometric intervention.
Visual training programme applied to precision shooting
Authors: Junyent Lluïsa Quevedo i , Fortó Joan Solé i
Published: July 2002

A three month visual training programme was conducted at the CAR of Sant Cugat (Olympic Training Center). Eleven members of ‘The Catalan Government Special Intervention Squad’ were used in a clinical trial. Pre‐test and post‐test results were obtained for pistol shooting, visual function, and psychological and physical states. Statistical analysis indicated significant gains in visual function and pistol shooting scores after the programme, while psychological (anxiety) and physical condition remained the same. Some conclusive statements can be made with regard to the relation of visual function improvement and shooting performance increment, after analysing the data. This improvement is evident in statistically significant post‐test gains in the following variables: 'phoria at distance, recovery points in fusional reserves at distance, analytical amplitude, negative relative accommodation, saccadic fixations, and accommodative facility at distance and at near. The rest of the controlled visual variables also showed clinical improvement.
Pirenzepine prevents form deprivation myopia in a dose dependent manner
Authors: Leech E. M. , Cottriall C. L. , McBrien N. A.
Published: July 2002

Previous studies have demonstrated that muscarinic antagonists, such as atropine and pirenzepine, block form deprivation myopia in avian and mammalian models. The aim of the present investigation was to establish dose–response curves for intravitreal and subconjunctivally injected pirenzepine and to determine receptor specificity. Chicks were monocularly deprived of form vision for five days and received daily injections of either pirenzepine or saline. Keratometry, retinoscopy and A‐scan ultrasonography of axial ocular dimensions were then taken. Intravitreally injected pirenzepine was effective at preventing form deprivation myopia in a dose dependent manner with an ED50 of 175 μg. A 500 μg dose totally prevented induced myopia (+0.9 D versus −13.7 D) and axial enlargement (−0.14 mm versus +0.32 mm). Daily subconjunctival injection of pirenzepine was significantly less effective in preventing form deprivation myopia. Form deprivation myopia could still be induced in animals which had undergone pirenzepine treatment. Pirenzepine was effective in preventing the axial elongation associated with experimental myopia in a dose dependent manner and via a functional not toxic mechanism.
Reversal of tropicamide mydriasis with single instillations of pilocarpine can induce substantial pseudo‐myopia in young adults
Authors: Gilmartin Bernard , Amer Adam C. , Ingleby Stuart
Published: July 2002

Pupillary dilation for diagnostic purposes has become an increasingly common procedure in UK optometry in recent years and the consensus seems currently to militate against the routine use of miotics; an eye that is judged safe to dilate is thought to be at minimal risk during the natural recovery phase to normal pupil size. Nevertheless, the optometrist does, on occasion, need to consider whether there might be some advantage in minimising the sometimes debilitating effects of cycloplegia and mydriasis produced in young adults by tropicamide. In this context we compare the effects of single instillations of two miotic agents: the α‐adrenoceptor antagonist thymoxamine HCl (0.5%), and the parasympathomimetic pilocarpine HCl (1 and 2%). Tropicamide was used to induce mydriasis in a group of 12 volunteer student subjects aged 20–26 years (7 male, 5 female; mean 21.67 years) selected to provide low (L; n = 4), medium (M; n = 4) and high (H; n = 4) iris pigment levels. Measurements of pupil diameter (Brocca pupillometer), Snellen visual acuity and accommodative amplitude (near point rule) were made every 3 min over a 90 min recording period for 4 trials: (1) a control condition whereby a miotic was not employed; (2) thymoxamine HCl 0.5% was instilled after 30 min; (3) and (4) pilocarpine 1% and 2% was instilled after 30 min, respectively. Tropicamide induced a mean increase in pupil area from 25 to 50 mm2 after 22 min which was generally sustained over the 90 min period and was enhanced for the lower pigment groups. Although a partial reversal was induced by thymoxamine (i.e. a mean decrease from 50 to 35 mm2 35 min after instillation), was not present with pilocarpine, there was clear evidence of a significant pilocarpine‐induced pseudo‐myopia which, when corrected with negative spheres, had mean values (in DS for pigment levels L, M, H) as follows: for 1%, 0.56 (L), 0.66 (M), 0.34 (H); for 2%, 1.17 (L), 0.71 (M), 0.44 (H). The pseudo‐myopic effects were transitory but, if present, became apparent within 30 min after instillation of pilocarpine and lasted for up to 80 min after completion of the drug trials. The results emphasise the need to monitor closely the potential pseudo‐myopic effects of pilocarpine, especially in light coloured irides where an adequate standard of vision for driving might be at risk. Further, reinstatement of an easily accessible formulation of thymoxamine (or dapiprazole HCl) should be encouraged.
Ocular dysfunction associated with mental handicap
Authors: Castañe M. , Peris E. , Sanchez E.
Published: July 2002

The aim of this article is to show the main general and ocular characteristics of a group of 46 mentally handicapped people of different IQ and age who were provided with visual care. Many different syndromes and neurological alterations have been described in the literature. The case types and number of people studied for each condition attending our clinics were: syndromes: Down's (25), Soto (2), West (2), Rubinstein–Taybi (1), triple X (1); neurological conditions: cerebral palsy (8), microcephaly (5), hydrocephaly (2). In our study the ocular findings were high incidence of ametropies: 58.7% hyperopia, 21.7% myopia, 19.5% astigmatism and 28% strabismus.
The aetiology of presbyopia: a summary of the role of lenticular and extralenticular structures
Authors: Gilmartin Bernard
Published: July 2002

Presbyopia is a condition of age rather than ageing and, as such, is devolved from the lamentable situation where the normal age‐related reduction in amplitude of accommodation reaches a point when the clarity of vision at near cannot be sustained for long enough to satisfy an individual's requirements. Most of our facility to accommodate has been lost by 55 years‐of‐age and subsequent deterioration in visual performance at near is attributable to characteristics of senescent vision familiar to the optometrist. Our understanding of the cause of presbyopia has then to be derived principally from our understanding of the mechanism of accommodation in young eyes. Hermann von Helmholtz did much to clarify these mechanisms, but despite much research in the 100 years since his death, there is still no consensus on their precise nature. This paper presents a summary of issues, past and present, which have figured in the literature on the physiology of accommodation and presbyopia, and confirms that the pathophysiology of presbyopia is likely to result from deterioration in structure and function of a number of inter‐related tissues. Changes in crystalline lens dimensions with age, the associated change in geometry of zonular attachments, and changes in viscoelastic properties of the lens capsule and lens matrix would, however, appear to be the principal correlates for the onset of presbyopia. Recent models of the biomechanics of accommodation have drawn attention to the feasibility of extralenticular contributions to presbyopia and have examined properties of the elasticity and leverage provided by posterior, anterior and tensile fibre systems. The stimulus for innovation in the correction and remediation of presbyopia is strong as at least 98% of individuals from the industrialised nations will survive until 45 years‐of‐age; it is salutary to note that the survival rate 100 years ago was only 60%.
The lacrimal lens as an assessment factor in hard contact lens fitting
Authors: Gowans M.
Published: July 2002

The fitting of hard contact lenses relies primarily on the evaluation of the findings of ‘K’ readings, the fluorescein pattern of the tear configuration and the interpretation of the lens movement upon blinking and the lens position after blinking. All of these methods have some disadvantages in the evaluation procedure: (a) keratometer readings measure cornical radius in a small and restricted area of the central cornea not in the larger area to eventually be covered by the lens (Bennett and Rabbetts, Clinical Visual Optics. Butterworths, London, UK, pp. 420–421, 19841); (b) the fluorescein pattern is sometimes unreliable especially in the presence of excessive tear flow; (c) lens movement, arguably the most reliable of evaluation methods, nonetheless requires some alternative back‐up technique. This presentation outlines the possibility of utilising the lacrimal lens as a useful additional procedure to the above when prescribing a lens curvature of choice. It should be pointed out that the technique discussed refers to spherical or near spherical corneas.
The risk of microbial keratitis with daily‐wear and extended‐wear use of disposable lenses
Authors: Radford Cherry F. , Minassian Darwin C. , Dart John K.
Published: July 2002

A pilot case‐control study indicated an excess risk of microbial keratitis (MK) with disposable soft contact lenses (DSCL). A larger case‐control study was conducted to separate the risks associated with daily‐wear (DW) and extended‐wear (EW) use of DSCL, and to determine whether there is an excess risk associated with the lenses after controlling for other variables.

Contact lens (CL) wearers presenting as new patients to Moorfields Eye Hospital Casualty over 12 months completed a questionnaire detailing CL use and hygiene practices. Cases were patients with presumed MK, according to established clinical criteria. Controls were patients attending with disorders unrelated to CL wear. Relative risks were calculated using conventional soft lenses (SCL) as the referent, and multivariable analysis was performed. DW and EW patients were analysed separately.

Among SCL wearers there were 89 cases, and 566 controls. Multivariable analysis confirmed a statistically significant increased risk with DSCL among both DW (×3.5) and EW patients (×4.8).

This study shows that, despite the proven reduction in less serious complications with the disposable regimen, there is an increased risk of MK with both DW and EW DSCL, even after controlling for other variables. Although patient and practitioner factors may contribute to these risks, it is likely that properties of some DSCL are partly responsible and require further investigation.
Spectral sensitivity as revealed by isolated step onsets and step offsets
Authors: Schwartz Steven H.
Published: July 2002

Opponent‐colour spectral sensitivity functions are traditionally elicited with increments; the temporal presentation of these increments is usually step onset and step offset. However, there are both physiological and psychophysical data suggesting differences in sensitivity for spectral step onsets and step offsets. The purpose of this study was to elicit opponent‐colour spectral sensitivity functions with isolated step onsets and offsets, and to compare the form and sensitivity of these functions. Spectral sensitivity functions were determined for large, long duration, step onset and step offset stimuli. Four human observers participated in the study. The opponent‐colour functions obtained for onsets and offsets are largely similar in both form and sensitivity. Of particular interest is the finding that there is no reduction in sensitivity for blue offsets. These data are consistent with recently published psychological data and apparently at variance with physiological data that suggest a paucity of S‐cone OFF‐neurones in the primate retina and dorsal lateral geniculate nucleus (dLGN).
Visual field defects due to spectacle frames: their prediction and relationship to UK driving standards
Authors: Steel S. E. , Mackie S. W. , Walsh G.
Published: July 2002

One male and one female subject wore a selection of ten current spectacle frames in random order. Monocular visual fields were assessed using an Aimark perimeter in accordance with UK Driver and Vehicle Licensing Authority (DVLA) guidelines. Of the ten frames, seven plastic frames produced an absolute scotoma intruding into a 120°× 40°‘letterbox’ area acting as a driving visual field template. Three metal frames gave a relative scotoma; however, our apparatus was too insensitive to plot these scotomata. Relevant frame and patient parameters were measured and entered into a computer program which enabled theoretical visual field defects due to a spectacle frame to be calculated. Good agreement is shown to be possible between actual and computed visual field defects. Spectacle frames can and frequently do cause visual field defects which may affect a driver's fitness to drive. Our data also show that a frame which allows an adequate field of vision at night could cause a marked visual field defect during daylight hours. A model and rule‐of‐thumb are given to determine the size of these potential defects and suggestions are given to minimise or eliminate them.
Multi‐meridional keratometry
Authors: Rosenfield Mark , Portello Joan K.
Published: July 2002

During conventional keratometry, the two principal meridia are identified and measurements of the anterior corneal curvature determined along these orientations. However, in cases of corneal irregularity, the principal meridia may be difficult to identify. Accordingly, the present study sought to evaluate two alternative procedures which do not require identification of the principal meridia. Instead, measurements of anterior corneal curvature were determined along either three or four preselected meridia and subsequently converted into the standard format for measurements of anterior corneal curvature. The study was performed on 25 visually normal subjects and the results compared with conventional two meridian keratometry findings. No significant differences were observed between the mean findings for the three and four meridian techniques. Furthermore, both procedures gave comparable results to the conventional two meridian method. Accordingly, multi‐meridional keratometry may be valuable in cases of irregular astigmatism, for example produced by keratoconus or scarred corneas, since measurements can be obtained without the necessity for identification of the principal meridia.
Optical consequences of asymmetries in normal corneas
Authors: Hemenger Richard P. , Tomlinson Alan , Oliver Katherine
Published: July 2002

A survey of videokeratographs of normal corneas shows many with substantial peripheral asymmetries. For sufficiently large pupils (5.5 mm in this study) these asymmetries lead to coma‐like axial aberrations large enough to produce measurable losses in vision in a number of cases. Starting from the output of a videokeratographic instrument, a method of estimating the optical effects of corneal asymmetries using Zernike circle polynomials is outlined. It is further shown that in a first approximation corneal asymmetries can be identified with the primary aberration coma and that this aberration is approximately due to a uniform gradient of refractive power across the cornea. Calculations for a representative case predict that a significant improvement in modulation transfer would follow from correction of this aberration.
Contrast and luminance as parameters defining the output of the VERIS topographical ERG
Authors: Brown Brian , Yap Maurice K. H.
Published: July 2002

The Visual Evoked Response Imaging System (VERIS I) topographical electroretinogram system (EDI Associates, San Francisco, CA) allows measurement of the response of large numbers of retinal areas simultaneously. This paper examines ERG responses derived with the VERIS system to changes in target contrast and to local reductions in luminance. There is a linear reduction of response with reductions of target contrast. Neutral density filters were placed over part of the display, to mimic the localised reductions in response which occur in glaucoma, age‐related maculopathy or diabetic retinopathy. There is a definite reduction in response seen with a 0.4 ND filter, indicating that the system should have similar sensitivity in detection of retinal lesions to the commonly used visual field analysis systems.
Reduced accommodation in children with cerebral palsy
Authors: Leat Susan J.
Published: July 2002

Accommodation in 43 subjects with cerebral palsy was measured objectively using a dynamic retinoscopy technique, which has already been shown to be reliable and repeatable. The subject's ages ranged from 3 to 35 years. Of these, 42% were found to have an accommodative response pattern which was different from the normal control group for his/her age. Nearly 29% had an estimated amplitude of accommodation of 4 D or less. The presence of reduced accommodation was found to be associated with reduced visual acuity, but was not associated with cognitive or communication ability, refractive error or age. The prevalence of other ocular disorders in this group is also high. These findings have developmental and educational implications.
The dynamics of tear flow within a phenol red impregnated thread
Authors: Blades Kenneth J. , Patel Sudi
Published: July 2002

A method for the laboratory production of a phenol red impregnated thread is described. Using the thread, tear flow was measured in the right eye of 2 groups of normal subjects: group I,n = 20, average age 26.2 years (± 5.6); and group II, n = 20, average age 56.4 years (± 13.8). Data were collected by placing a thread over the lower lid margin for a time period of 15 s. A further seven threads were inserted at 5 min intervals for periods increasing by 15 s up to 120 s. A significant difference in mean thread wetting between the two age groups was found for thread insertion times of 30, 60 and 90 s. For each eye, the rate of thread wetting was exponentially related to the period of thread insertion. Thread wetting and the constant of the exponential were not found to be gender dependent. Simulating the tears in the lower fornix, using a bath of saline, it was concluded that the exponential constant was a property of thread material and not tear fluid. For practical purposes, the rate of thread wetting reached equilibrium by 120 s where mean total thread wetting was 19.5 mm (± 6.5). The typical flow of tears (y) in mm/s, along the phenol red thread can be described by: y = 0.16 + 0.47e−0.0283t where t is the period of thread insertion.
Deceptive discs ..!
Authors: Pawson Pete
Published: July 2002

Discrimination between normal and glaucomatous optic discs is notoriously difficult, even for ophthalmologists specialising in glaucoma. This poster will present optic disc photographs, together with their corresponding visual fields, in order to highlight this difficulty. The various possible disc, field and intraocular pressure combinations will be explored, and potential explanations for non‐correlation between these variables will be offered. Emphasis will again be placed upon:

1. The value of visual field examinations when screening for glaucoma (Tuck and Crick, 1993).

2. The relevance of disc size in the interpretation of C : D ratios (Jonas and Dichtl, 1995).

3. The fact that raised intraocular pressure is a risk factor for glaucoma, rather than a diagnostic criterion (Sommer, 1989).
Biographical and clinical characteristics of a low vision population
Authors: Doorduyn Katie , Harper Robert
Published: July 2002

A retrospective survey of the optometry clinics at Manchester Royal Eye Hospital was undertaken in order to define the biographic and clinical characteristics of the population being provided with low vision rehabilitation. For the year quarter July‐September 1994, 288 patients were identified as having attended the low vision clinic. The hospital case notes were available for examination in 273 cases (94.8%). The results presented here relate to this latter sample of patients.

Analysis of the records revealed that the major diagnostic categories were ARMD (55.7%), glaucoma (10.6%), diabetic retinopathy (8%), other macular disorders (5.9%) and myopic degeneration (5.5%). The median age of patients was 78 years (range 7–104) and the male : female ratio was 0.87 (i.e. 53.4% female). Distance visual acuities on entry to the clinic were 6/60 or better in 72.5% of the sample. A total of 141 patients (51.6%) were known to be registered as blind or partially sighted.

A new spectacle prescription was issued to 21.6% of patients. The most frequent low vision aids (LVAs) issued were stand magnifiers (147 illuminated and 46 non‐illuminated), hand‐magnifiers (67 issued) and distance monocular/binoculars (51 issued). With appropriate low vision provision, 84.5% of the sample achieved a near acuity of N8 or better. A total of 371 LVAs were issued, representing an average number of 1.36 LVAs per patient. The total cost of all LVAs issued amounted to £7818.81, giving an average cost of £28.64 per patient.

This survey has provided a useful insight into the characteristics of both the population our service provides and the LVAs prescribed. Studies to measure the outcomes of our low vision provision are presently being carried out.
The effect of an artificially elevated intraocular pressure on the central corneal curvature
Authors: Douthwaite William A. , Lam Andrew K. C.
Published: July 2002

Twenty‐three optometry students with normal corneal condition were recruited. The intraocular pressure and central corneal curvature of the right eye were measured in a sitting and a 30° head‐down posture. The mean (standard deviation) IOPs before and during posture change were 1 5.6 (2.4) mmHg and 22.1 (2.3) mmHg respectively. This 6.5 mmHg mean rise in IOP was found to be statistically significant which is similar to the results from previous studies. The mean changes in radius of corneal curvature and the orientation of the axis of the vertical principal meridian were 0,02 mm (SD 0.025 mm) and 2.4° (SD 10.4°) respectively. No significant variation was demonstrated on these keratometric results due to the 30° head‐down posture. The maximum change in radius of curvature was only 0.055 mm for one subject. Perhaps this amount of pressure rise was not sufficient enough to distort the corneal surface centrally. Another possibility could be an even distribution of the elevated pressure around the cornea, or the distribution of pressure is not even but could not be revealed by a conventional keratometer.
On‐eye power characteristics of soft contact lenses
Authors: Plainis Sotiris , Charman W. N.
Published: July 2002

The power effect of a soft contact lens on the eye is a function of its off‐eye power, the manner in which the lens flexes on the eye, lens hydration changes and the cornea. The innovative aspect of the present study was the employment of a high‐illumination keratometer (Carl Zeiss Jena) which allowed us to obtain front and back surface keratometric readings when single‐vision lenses were in position on the eye. The on‐eye power of the lens could then be calculated from these readings, with the assumption that the centre thickness and refractive index of the lens corresponded to those in vitro . The estimates of the on‐eye powers agreed closely with the results indicated by over‐refraction and showed that all the lenses used closely conformed to the corneal shape and the tear lens formed was of minimal power (≤0.25 D). Moreover, comparison of in‐vitro with on‐eye power estimates indicated that the positive single vision lenses lost power on the eye (mean difference −0.38 D), while the negative ones maintained their power (mean difference −0.02 D). The findings of the present study appeared to be in agreement with the predictions of most of the flexure models developed in the past.
The light scattering characteristics of the eye
Authors: Hennelly M. L. , Barbur J. L. , Edgar D. F. , Woodward E. G.
Published: July 2002

Aim: To validate a new method for the measurement of scattered light in the eye. In addition, normal values and results of subjects with keratoconus, cataract and corneal dystrophy will be demonstrated.

Method: The scatter programme is implemented on the P__Scan 100 system. The system involves the use of high luminances and extended stimuli modulated sinusoidally. It reveals three parameters; n the scatter index which describes the distribution of scattered light from the scattering source; k, which describes the overall light scattered and a new index k′ known as the integrated straylight parameter. k′ provides an alternative to the commonly used straylight parameter, k.

Results: Preliminary results in a small sample of normals showed k′ to be affected by age, diurnally, and by the menstrual cycle. Little variation in k′ was found between the ages of 16 and 42 years, with an increase found after the age of 60. A diurnal variation was found, with increased values of k′ on waking, which may be related to variation in corneal thickness. A variation in k′ with the menstrual cycle was noted. All values, i.e. n,k, k′ were found to be affected by keratoconus, cataract and corneal dystrophy.

Conclusion: k′ is an important parameter in the quantification of scattered light. The results obtained give an insight into the patient's symptoms of glare, essential in the timing of conducting penetrating keratoplasty.

Acknowledgement: M. L. Hennelly was supported by a College of Optometry Studentship.
Reproducibility of topographic measurements of the optic nerve head with the Heidelberg Retina Tomograph using separate and imported contour lines
Authors: Roff E. J. , Hosking S. L. , Barnes D. A. , Gibson J. M.
Published: July 2002

Purpose: To investigate whether topographical measurements of the optic nerve head are more reproducible when the contour line is redrawn for each image as opposed to imported using the Heidelberg Retina Tomograph (HRT).

Introduction: Optic nerve head topography can be measured in vivo using Confocal Scanning Laser Ophthalmoscopes such as the HRT. Image analysis requires that the area of the optic disc is defined by subjectively drawing a contour line around Elschnig's ring. The HRT software can export this contour line between images for a subject, or the contour line can be redrawn.

Method: Ten eyes of ten normal volunteers (40–60 years) were analysed with the HRT. Seven 10° images of the optic disc were taken by one observer for each randomly selected eye. Focus and scan depth settings were kept constant. All available stereometric parameters were analysed using three methods: (1) with a separately drawn contour line for each individual image, (2) with a contour line imported from the first image into subsequent images of the series, (3) by repeatedly redrawing the contour line for a single image from each eye. All contour lines were drawn by one observer. Mean co‐efficients of variation were calculated for each parameter for the three methods.

Results: The mean co‐efficient of variation for the parameters ranged from 1.7–23.4% (method 1), 0–20% (method 2) and 1.6–13.4% (method 3).

Conclusion: These results show that redrawn contour lines increase variability. Topographical measurements of the optic nerve head are more reproducible if the contour line is imported across subsequent images rather than redrawn for each individual image.
Longitudinal studies of visual and cognitive development in young children with Down's syndrome
Authors: Cregg M. , Woodhouse J. M. , Parker M. , Pakeman V. H. , Fraser W. I. , Sastry P. , Lobo S.
Published: July 2002

As part of a long‐term study of visual and cognitive development in children with Down's syndrome, we are monitoring visual functions, including visual acuity, accommodation, refractive error, as well as scores on Bayley Scales of Infant Development in a cohort of 64 children throughout South and West Wales. Cross‐sectional data, presented at a previous meeting, suggest a remarkable similarity between acuity and cognitive scores, in that both progress rapidly in the early months, and undergo a sudden rate change at the age of 2 years.

We now have a sufficient longitudinal data to re‐examine the progress of these two functions. Results for 12 children, each seen four times at similar ages, were analysed. Those children whose visual acuity falls outside the normal range at later ages, also show significantly lower cognitive scores, when compared to the children with normal visual acuity.
Symmetry detection in amblyopia
Authors: Barrett B. T. , Herbert A. M.
Published: July 2002

Purpose: It has been suggested that the term tarachopia, meaning ‘distorted sight’, provides an accurate description of the visual deficit in amblyopia. This follows psychophysical findings of spatial inaccuracy in amblyopia, as well as subjective reports of perceptual distortions by amblyopic observers. Mirror symmetry is a salient feature in normal human vision and its detection is critically dependent upon the spatial relations between the elements of the pattern. This study investigates whether the perceptual distortions in amblyopia extend to mirror symmetry detection.

Methods: Three strabismic and three non‐strabismic amblyopes participated in the experiment (acuity range 6/9 to 6/90). Symmetric and random dot patterns were briefly presented (<250 msecs) at three retinal locations (centred at fixation, and 4° to the left and right of fixation). The patterns were generated and displayed on a Macintosh computer. After each stimulus presentation the subject was required to press one of two keys to indicate whether the pattern was symmetrical or random. The d′ statistic was computed for three symmetry orientations (H, V, and 45°) for each of the three retinal locations.

Results: Amblyopic‐eye performance was equivalent to fellow‐eye performance in 5 of the 6 amblyopes tested. In the remaining amblyope symmetry detection in the amblyopic eye. This is likely to have resulted from reduced visibility of the dot pattern since the acuity in this eye was 6/90.

Conclusions: The ability to detect mirror symmetry in briefly presented dot patterns is not affected by amblyopia.
Efficiency of human pattern recognition as a function of the range of size randomization
Authors: Näsänen Risto , Syväjärvi Antti , Rovamo Jyrki
Published: July 2002

We measured pattern recognition efficiency for numerals in spatial noise. The numerals of Century Gothic typeface were filtered with a two octaves band‐pass filter. Different magnifications (ranging from one to four) of the filtered numerals were used. The contrast energy across magnifications was constant. In the experiment, the different magnifications were selected for presentation in a random order. Using an n‐alternative forced‐choice method, recognition thresholds were measured as a function of the range of magnifications. The results obtained from human observers were compared with those of an ideal (‘template matching’) pattern recognition observer. The thresholds of the ideal observer were obtained by computer simulations. Human results were expressed in recognition efficiency defined as the ratio of the ideal and human energy thresholds. With no size uncertainty the efficiency was about 20%, and when the possible magnifications varied by a factor of four, the efficiency was about 75%. Thus, human recognition efficiency became better with increasing size uncertainty. The result may be interpreted so that human vision automatically assumes that the retinal sizes of objects are not fixed but vary, for example, because of varying viewing distance.