bluuebunny/crossref_metadata_2025 huggingface dataset:
Mutual workers’insurance: A historical outline
Authors: van der Linden Marcel
Published: December 2007

This article focuses on the historical development of small workers’mutual insurance societies whose members manage the fund themselves. The article begins by describing the remarkable similarities in terms of characteristics and development of these societies in different places and periods. It then discusses various non‐directly democratic competitors in the field of social insurance and forms of State intervention. Finally, the article attempts to explain why competition from the private sector and State interventions forced directly democratic societies to choose between bureaucratization, marginalization and disbandment.
The labour movement and mutual benefit societies: Towards an international approach
Authors: Dreyfus Michel
Published: December 2007

The comparative history of the mutualist and workers’movements shows up several notable points of convergence, from their beginnings up until the Second World War. They were branches of a common tree: tradesmen's and workers’guilds were more often than not at the origin of union and pre‐union organizations and mutual aid societies. The two movements also developed in parallel over the course of the two industrial revolutions of 1780‐1840 and 1880‐1890. Despite this, their paths began increasingly to diverge. Setting out from the same essentially craft‐based social milieu as the unions, the mutualist movement gradually took root among the lower‐middle and middle classes, the civil service and the military. The mutualist ideology of a common good shared among the social classes was the antithesis of the prevailing ethos in the union movement, of which class struggle was the defining attribute. Finally, the aims of the two movements also diverged: on one hand the trade unionists, engaging in mass and sometimes violent action in support of immediate demands; on the other, the mutualists, working away at their necessarily long‐term administrative tasks. From the last quarter of the nineteenth century on, therefore, the mutualist and workers’movements entered into a process of increasing diversification.
Using work, health and sick leave to predict work disability
Authors: de Winter Cornells R.
Published: December 2007

In the Netherlands, a situation has developed in which there is one permanently disabled person for every seven to eight people active in the workforce. This is an economic emergency, for which countermeasures have been taken. The employer is made in large part financially responsible for employees' sickness absence and work disability and, at the same time, is obliged to use the professional support of a Health and Safety Service (HSS). It stands to reason that in this situation, making use of the HSS, the employer is motivated to prevent sickness absence and disablement of employees as effectively as possible. Preventing work disability critically depends on being able to predict disability through early identification of the future disabled. In order to develop a prediction procedure at the individual level, the present prospective study was conducted. Some 3,500 employees were followed for up to five years. Predictors of disability were sought among employees’opinions on their health, work, and working conditions as measured by the Questionnaire on Work and Health (QWH), and sick leave data. The QWH items are concerned with health, work and job circumstances. As expected, most (two thirds) cases of disability occur in male employees aged 50 and over. Disability in this group is strongly predicted by complaints about work strain, health, and illness behaviour, with the odds being in the 4 to 6 range. The odds can be raised to over 10 by including sick leave data. These predictions warrant individual preventive interventions. The results, taken together, speak for the predictive validity of the questionnaire and its usefulness to occupational health services in combating disability.
The financing of retirement schemes, savings and growth
Authors: Artus Patrick
Published: December 2007

This article discusses the various elements affecting the choice between pay‐as‐you‐go systems (with optional capital accumulation) and compulsory capital accumulation systems to finance retirement schemes. The choice of system depends not only on their performance, but also on other elements covered less frequently by analyses, such as the effect on real wages and the real equilibrium interest rate, and various possible imperfections (myopia, limits on debt levels). Attention is also given to the possible explanations for the chronic lack of savings and to how the choice of retirement system may be affected by the weight given to short‐term considerations (the ways in which different systems react to economic or demographic fluctuations, for example).
Social security support for informal caring in the Republic of Ireland
Authors: Cousins Mel
Published: December 2007

This article looks at the policies of social security support for informal carers in the Republic of Ireland. The demographic context and the overall policy context are first outlined, with a brief summary of the available institutional and community care services. The development of social security policies is subsequently examined, tracing the development of specific social security support for informal caring since the late 1960s and looking, in particular, at the recent establishment of a means‐tested carer's allowance in 1990. Some of the issues surrounding social security and informal carers are then discussed, including the different strategies which can be adopted in providing support for informal caring and the factors which influenced the development of support in Ireland.
Benefits and incentives for lone parents: A comparative analysis
Authors: Whiteford Peter , Bradshaw Jonathan
Published: December 2007

One of the most striking trends over the past 20 years is the growth in the number of lone parent families in developed countries. This article provides an analysis of the structure of incentives in benefit systems for lone parents in a cross‐national perspective, using data from a recent comparative study of the systems of support for families with children in 17 countries (the members of the European Union, Australia, Japan, Norway, Sweden and the United States). The article compares the level of benefits for lone parents and takes into account the impact of housing costs, health costs, and education and preschool provision. It assesses the possible incentive effects of different systems through a comparison of the financial positions of lone parents not in paid employment, lone parents in the labour market and other family types.
Reversing “the inadvertent nationalization of fatherhood”: The British Child Support Act 1991 and its consequences for men, women and children
Authors: Land Hilary
Published: December 2007

During the 1980s, with the growth in divorce, remarriage and births outside marriage, men's responsibilities for children and their mothers have been reviewed. In Great Britain, the Child Support Act 1991, following a decade in which the number of lone parents increased by 50 per cent and the proportion claiming state benefit increased from one‐half to two‐thirds, is attempting to shift lone mothers from dependence on the State to dependence on the biological father of their children. This has raised controversial issues concerning women's and children's claims on the State as citizens in their own rights; the balance between a man's private duty to maintain and provide care for children (by maintaining their mother) and his public duty to reimburse the State for doing so; and the legitimacy of trade‐offs between claims on family “property” and claims to maintenance previously exercised in the courts. The individualistic system of English family law, in contrast to the law in Scotland and continental Europe, is part of the context within which these changes are taking place. So, too, is the fall in economic activity rates of lone mothers, which are among the lowest in the European Union.
Principles and practice of social security payments for care
Authors: McLaughlin Eithne , Glendinning Caroline
Published: December 2007

This article examines the dimensions which determine whether national social security systems make payments towards the costs of long‐term care needs and whether they do so where these needs are met within the family; what kinds of payments are made and to whom; and what levels these payments are set at. The article is based on empirical material from five European Union countries (the United Kingdom, Ireland, France, Italy and Germany). We argue that differences between countries along three dimensions account for most of the diversity between national systems in this field. These dimensions are the allocation of responsibilities and powers to local versus central levels of government; assumptions of to whom long‐term care represents a “risk”; national principles of subsidiarity and the relationship between the family and the State. This is, however, a field undergoing change (albeit mostly incrementalist and ad hoc) in the face of the demands placed on social welfare systems by growing levels of disability (related to the growth of elderly populations) and demands from women's movements and disability movements for recognition of their needs within social welfare systems.
The evolution of the welfare state: Shifting rights and responsibilities for the old
Authors: Hudson Robert B.
Published: December 2007

This paper juxtaposes discussion of pressures impinging on the contemporary welfare state with material highlighting remarkable changes taking place in the condition of aged populations in industrial nations. Toward acknowledging both the pressures and the new exigencies facing many who are now old, I suggest a means for reassessing how we weigh and address different risks facing the old. Universalism and adequacy are taken as bedrock concerns, but how and where those principles are applied is opened to new exploration.
The pension system in Slovenia: Past developments and future prospects
Authors: Stanovnik Tine , Kukar Stanka
Published: December 2007

Most public pension systems in Europe are faced with unfavourable demographic tendencies and stagnating economies. The Slovene public pension system is no exception to this rule and we provide a description of relevant demographic and economic developments since the early 1980s. It has been shown that the large increase in pensioners was very much due to the increase in early retirement. This social policy measure — while alleviating tensions on the labour market — is also directly responsible for the sharp increase in the pension contribution rate, currently amounting to some 48 per cent of net wages. The large contribution rate is also due to the fact that various pension rights, which actually represent concessions to diverse special‐interest groups, are funded through contributions and not by the State budget. We argue that certain reform measures—primarily aimed at reinforcing the contribution‐benefit linkage—are warranted. While the pay‐as‐you‐go system can hardly negate the principle of vertical equity, a more strict observance of the principle of horizontal equity would be beneficial for the social cohesion and stability of the pension system.
The advantages and disadvantages of different social welfare strategies
Authors: Thompson Lawrence H.
Published: December 2007

This paper presents a framework for consideration of change in or reform of social welfare systems. The author describes characteristics of the approaches to providing social welfare most commonly used in North America and western Europe. These include social insurance, employer mandates, individual mandates, voluntary arrangements (tax expenditures), means‐tested programmes, and universal programmes (demogrants). He then evaluates each of the approaches in terms of its ability to achieve a set of social and economic objectives. The social protection objectives include treating people with dignity and respect, assuring complete coverage, equitably distributing costs and benefits, and operating efficiently to lower overhead. The objectives important to promoting a healthy economic environment include encouraging individual saving and work effort, fostering government fiscal responsibility, and facilitating smooth market functioning. The author concludes that there is no one correct way to organize social welfare systems, that each approach has strengths and weaknesses, and that different societies will attach different priorities to different objectives. Thus, as social goals change, we may expect that the particular mix of approaches used will also evolve and change over time.
ITALY
Authors: Salafia Antonio
Published: December 2007

A radical overhaul of the pension system is under way in Italy. A number of partial reforms had already taken place; but the draft Bill dated 17 May 1995 proposes a new structure, compatible with the financial and demographic situation of the country. After analysing the critical weaknesses in the present system, the author goes on to describe the general lines of the reform provided for in the draft Bill, explaining succinctly the principal innovations. In particular, he describes the new system of calculating pensions and illustrates the proposed changes to the systems of invalidity allowances, disability pensions and adjustment upwards to the established minimum. This is followed by a description of the new rules governing contribution‐based old‐age and long‐service pensions and the proposed changes in the automatic adjustment system. The author approaches the problem of adjusting contributions to the new system and describes the principal changes introduced in line with the general principles underlying the conditions for entitlement to pensions under that system. This description and assessment of the main outlines of the new reforms of the pension system ends with a discussion of complementary pension insurance and an initial estimate of the savings to which the new system will give rise.
Pension reform, the stock market, capital formation and economic growth: A critical commentary on the World Bank's proposals
Authors: Singh Ajit
Published: December 2007

Proposing far‐reaching reforms to pension systems, the World Bank has recently suggested that the existing pay‐as‐you‐go systems in many rich as well as poor countries should be replaced by fully funded, mandatory, preferably private pensions, as the main pillars of the new system. It argues that these reforms will not only benefit pensioners but also enhance savings, and promote capital formation and economic development. This paper provides a critical examination of the Bank's theses and concludes that it has adopted a one‐sided view of the relationships between the key critical variables. The proposed reform may therefore neither protect the old nor achieve faster economic growth.
The institutional design of the Australian Welfare State
Authors: Castles Francis G.
Published: December 2007

This paper seeks to compare and contrast the character of social policy in Australia with that in other OECD countries by focusing on the distinctive design features of the institutions constituting the wider context of Australian social policy provision. The three substantive sections of the paper successively summarize the distinguishing features of the institutional design of Welfare State provision in continental western Europe, Scandinavia and Australia; outline the wider institutional context of social policy in Australia; and examine the extent to which the distinctiveness of the institutional design of the Australian Welfare State has led to different patterns of policy outcomes from those in other nations.
Structure and legitimation of statutory accident insurance: A comparative legal view
Authors: Fuchs Maximilian
Published: December 2007

Accident insurance schemes are among the most widespread systems of social security. However, the need for separate such schemes is occasionally questioned in international statements and scholarly contributions. In the context of these kinds of criticism, this article sets out the standard bases for accident insurance. The unity of prevention, rehabilitation and compensation as the common characteristic structure of individual schemes is presented from a comparative legal viewpoint. The central significance of the principle of self‐management is also emphasized. With regard to their economic efficiency, which is supported by statistics, the criticism levelled at accident insurance schemes is shown to be unconvincing. Views calling separate schemes into question on the grounds of equity are also reected.
The social protection of the unemployed
Authors: Van Langendonck Jef
Published: December 2007

Unemployment is the most basic risk covered by social security. Sickness, accident, maternity, incapacity, old age or even death can be considered as special cases of interruption of earnings. Unemployment is the standard case, where a worker loses earnings simply because he or she is unable to find gainful employment, without reference to any particular causality. Nevertheless, the unemployment branch is very often treated rather poorly, in comparison with other branches of social security. In most countries – except the United Kingdom – it was created much later than other branches, and it involves a larger part of assistance, as opposed to insurance. Usually, fewer people are covered against the risk, the conditions for entitlement are stricter, the benefits tend to be lower and shorter in duration, and controls and sanctions are more severe.1 People are generally worse off when their loss of earnings is the result of a dismissal rather than disease or accident. In this contribution we try to analyse the reasons why unemployment has such a relatively poor status in social security. And we examine the extent to which this difference of treatment can be considered a form of discrimination and, in some cases, contrary to the basic principles of international social law.
THE SIGNIFICANCE OF INADEQUATE CONVERGENCE
Authors: Pickwell L. D. , Hampshire R.
Published: December 2007

Abstract Two methods for clinical assessment of convergence difficulties were considered in relation 10 the symptoms reported in a sample of 455 patients; 110 of these patients showed poor convergence by one or both methods. Poor convergence movements were found to be associated with dccompensated exophoria for near vision. No evidence was found to associate a near‐point of convergence greater than 10 cm with a high incidence of symptoms, and this appears to be a less appropriate clinical norm than the observation of a normal convergence movement from a distant to a near target (jump convergence). Abnormal convergence movements (poor jump convergence) occurred more frequently than a receding near‐point of convergence and were also more frequently associated with symptoms. It is concluded that observation of jump convergence is a simple, quick and valuable clinical procedure for the assessment of the adequacy of convergence in relation to the normal near working distance.
A COMPARISON OF THE BRITISH NUMBER PLATE AND SNELLEN VISION TESTS FOR CAR DRIVERS
Authors: Drasdo N. , Haggerty C. M.
Published: December 2007

Abstract The British number plate lest and the Snellen lest of visual acuity are compared. The observations of 60 subjects. 30 of whom have failed (he official number plate test, are analysed statistically. It is found possible to csiiiiunt1 the probability of a subject having a specified Snellen acuity, reading a number plate of the 3 1/2 (80 mm) symbol type, at 67 ft, (‐20.5m). It is considered, however, that the probability of passing the official number plate test is a different value and this is also shown to be estimated from the Snellen visual acuity. The calculations based on the sample of candidates who had failed the number plate test suggest that a driving test candidate with a Snellen decimal acuity of 0.55, or approximately ft/122 in clinical notation, has a 50% chance of passing the number plate test, but the level of visual acuity which would fail the same number of candidates as the number plate test is deduced from an approximate population model, to be 0,6, or 6/9+2. Many other quantitative estimates relating the two tests are given in the text and accompanying tables and figures.
A SUGGESTION FOR THE ORIGIN OF ECCENTRIC FIXATION
Authors: Pickwell L. D.
Published: December 2007

Abstract Several theories on the cause of eccentric fixation in sirabismic amblyopia have been advanced which conflict with the assumptions underlying the traditional explanation. This paper does not discuss these newer theories but recognizes that there is more than one pattern of comitant squint and suggests that there may be more than one mechanism which can produce eccentric fixation. An explanation founded on the theories of fixation disparity of Goersch (1978) is put forward. It is suggested that, where binocular Stresses occur at an early age, these can lead to sequence starting with fixation disparity and deteriorating into micro‐squint, with identity of (he angles of eccentric fixation, abnormal retinal correspondence and deviation.
THE EFFECTS OF CENTRAL AND PERIPHERAL REFRACTION ON CRITICAL FUSION FREQUENCY
Authors: Jennings J. A. M. , Charman W. N.
Published: December 2007

Abstract The critical fusion frequency (CFF) of each eye of one subject is measured for various combinations of focus and retinal position. Large (50 min arc) and small (8 min arc) flickering sources arc used. With the 8 min are source, the axial CFF is very sensitive to defocus and is halved by 2.00 DS of blur. The retinal periphery is less sensitive to defocus, and (he naturally occurring oblique astigmatism of the peripheral media is typically insufficient to substantially affect CFF.
THE EFFECT OF COLOUR OUTPUT OF INTENSIFYING DEVICES ON ACUITY IN PIGMENTARY RETINAL DEGENERATION
Authors: Taylor S. P.
Published: December 2007

Abstract Developments in phosphor technology have resulted in the possibility of producing intensifying devices with a variety of output colours. The present pilot study investigates the effect of phosphor colour on acuity performance in subjects suffering from pigmentary degeneration of the retina. The results of this study combined with previous data on dark adaptation and colour are used to provide recommendations regarding the most suitable intensifier output colour for such subjects.
MOOD JUDGEMENTS IN BLACK AND WHITE PICTURES AS A FUNCTION OF TONALITY AND POLARITY
Authors: French Chris , Taylor Jill , Trimby Steve
Published: December 2007

Abstract The importance of line, shape, texture and colour in the aesthetic response to pictures is well established. This study seeks to study one aspect of colour, the distribution of light and shade, and to see how this affects a picture's mood. It follows the suggestion of Graves in looking specifically at two factors in tonality, contrast and lightness, as well as polarity. Subjects were requested to select which version of a picture best suited a particular mood word. The results confirmed the importance of the stimulus variables investigated and indicated a degree of consistency between different pictures.
THE MARION LECTURE: ULTRASOUND IN OPHTHALMIC OPTICS*
Authors: Storey J. K.
Published: December 2007

ABSTRACT A personal trobute to H. B. Marion is given, together with an outline of some of his achievements. The use itf ultrasound for visualization through optically opaque areas due to various abnormal ocular conditions h described. Measurement of the eye with it relationship to refraction and the calculation of the power of a ICTTS implant is considered. The help that Ultrasonography can offer 10 the ophthalmic optician is illustrated with A‐ and B‐scan traces.
AGE‐DEPENDENCE OF HUMAN REFRACTIVE ERRORS
Authors: Saunders Harold
Published: December 2007

ABSTRACT Applying a method or vectorized summation of refractive corrections, ihis paper sets out to examine the behaviour of the associated parameters, the sphere, the cylinder power and the axis of astigmatism. It introduces novel methods of determining their age‐dependence and establishes their mathematical relationships.
AUTOMATED REFRACTION IN APHAKIA– I. ITS ACCURACY AND REPEATABILITY COMPARED TO A SINGLE‐PRACTITIONER CONVENTIONAL TECHNIQUE
Authors: Guillon Michel
Published: December 2007

ABSTRACT The accuracy and repeatability of an i.r. electronic objective optometer (the Ophthalmetron)is studied in aphakia. it is shown that the Ophthalmetron is a good alternative to retinoseopy in terms of accuracy and repeatability, but will fail to deliver imerpreiable results in 20% of cases.
SOME THEORETICAL FACTORS GOVERNING THE ACCURACY OF CORNEAL‐THICKNESS MEASUREMENT
Authors: Patel S.
Published: December 2007

ABSTRACT The major methods of determining corneal thickness are briefly reviewed. Theoretical expressions are derived for the relative error in the climate of corneal thickness, in terms of the errors in such parameters as the assumed radius of curvature and refractive index of the cornea. The relevance of these results to practical studies of corneal‐thickness, variation is discussed.
CORNEAL POWER AND VISUAL ERROR
Authors: Saunders Harold
Published: December 2007

Abstract The role played by (he power of the cornea in the composition of the total visual error is investigated. A connexion between them is made by analysing two sample populations. Elimination of corneal power from the total visual error determines the residual error which is due to sources other than the cornea.
COMPUTER SIMULATION OF EXTRAOCULAR MUSCLE CO‐OPERATION: AN EVALUATION
Authors: Clement R. A.
Published: December 2007

Abstract This paper is concerned with specifying how extraocular muscles co‐operate in moving the eye, A set of assumptions is described which enable ibis lo be done with enough precision for: i computer model of the actions of the extraocular muscles to be set up. The behaviour of the model and its validity arc then evaluated.
MEASUREMENT OF ACCOMMODATIVE AMPLITUDE IN AMBLYOPIA
Authors: Hokoda Steven C. , Ciuffreda Kenneth J.
Published: December 2007

Abstract Monocular accommodative amplitudes were measured in amblyopic individuals by the subjective minus lens push‐up techniques and by the objective dynamic retinoscopy. Accommodative amplitudes were always reduced in amblyopic eyes using the minus lens and retinoscopy techniques, but not with the push‐up technique which Inflated this measure, Owing to difficulty in detecting defocused stimuli with the amblyopic eye. it is suggested that the objective retinoscopic technique be used by clinicians for accurate assessment of accommodative amplitude in these patients.
CORNEAL TRANSPARENCY CHANGES RESULTING FROM OSMOTIC STRESS
Authors: Stevenson Ronald , Vaja Nat , Jackson Jonathan
Published: December 2007

Abstract Corneal thickness and transparency changes were measured following exposure of the cornea to various levels of osmotic stress. Bathing the cornea in hypotonic solutions of NaCl caused an increase in corneal thickness and light scatter within the cornea.

Transparency changes with hypotonicity were determined by comparing the relative brightness of haloes around a bright lamp source for the various concentrations of NaCl solutions. Corresponding corneal thickness changes were determined by pachometry.

A nearly linear relationship was found between solution hypotonicity and the degree of corneal swelling, whilst an exponential relationship was found between hypotonicity and relative halo brightness. The rate of corneal recovery from osmotic stress was found to be constant with different degrees of tonicity, although the rate of thickness recovery was much slower than the recovery from haloes.
THE WORKING THRESHOLD APPROACH TO FRIEDMANN VISUAL FIELD ANALYSER SCREENING
Authors: Gutteridge Ian F.
Published: December 2007

Abstract Central visual field screening of 2223 eyes without field defects was conducted with the Friedmann Visual Field Analyser Mark II. There was wide variation in the filter setting at which all stimuli were seen and in the working threshold relative to the recommended age filter. The ability to see all stimuli at settings higher than the age filter was found in 803 eyes (36.1%). The difference between mean working threshold and the age filter ranged from 0.22 to 0.40 log units, being greatest in middle age groups. The performance of the screener in correctly identifying normal eyes was thus improved with the working threshold approach, as the criterion for depression of sensitivity was an individually determined threshold.
OPTICAL THERAPY IN STEELE‐RICHARDSON‐OLSZEWSKI SYNDROME
Authors: Chou B. R. , Strong J. G. , Woo G. C. , Holterman J. A.
Published: December 2007

Abstract A case report on the Steele‐Richardson‐Olszewski syndrome is presented in this paper. The clinical findings are shown to be due to the physiological changes arising from progression of the disease. The low‐vision aspects of this case and its disposition are also discussed.
VALIDATION OF THE HOLMES‐WRIGHT LANTERNS FOR TESTING COLOUR VISION*
Authors: Vingrys A. J. , Cole B. L.
Published: December 2007

Abstract The recently introduced Holmes‐Wright Type A and Type B lanterns and the Farnsworth lantern were administered to 100 observers with normal colour vision and 100 observers with defective colour vision. With the fail criteria adopted, all normals passed the Holmes‐Wright Type A lantern and with one exception all normals passed the Farnsworth lantern. However, 8% of normals failed the more difficult Holmes‐Wright Type B lantern. It is noted that the normals who fail this lantern test appear to do so not because of poor colour discrimination but because the coloured stimuli presented by the lantern have a point brilliance close to the average chromatic threshold. About one‐third of the colour vision defective group passed the Farnsworth lantern and between 14 and 17% passed the Holmes‐Wright Type A lantern depending on the test procedure used. Only two mild deuteranomals in the sample of 100 colour abnormal observers succeeded in passing the Holmes‐Wright Type B lantern. Dichromats and severe anomalous trichromats fail all three lanterns so that those who pass are all mild anomalous trichromats. A significant proportion of protanomals pass the Farnsworth lantern and some protanomals pass the Holmes‐Wright Type A lantern despite their reduced sensitivity to red light and correspondingly reduced signal range for red signals.
MECHANISMS OF ACCOMMODATION AND REFRACTIVE ERROR*
Authors: Garner Leon F.
Published: December 2007

Abstract The classical or Helmholtz theory of accommodation has formed the basis of optometric practice for many years. This theory maintains that the ciliary muscle receives only parasympathetic innervation and that the position of rest in the emmetropic eye lies at optical infinity. The suggestion of a dual sympathetic/parasympathetic innervation to the ciliary muscle also dates from the last century. Recent studies indicate that the “dark focus” or resting point of accommodation lies at some intermediate distance and that the refractive state in the absence of an adequate stimulus represents the tonus position of the ciliary muscle for minimal autonomic innervation. This paper considers the possible role of a sympathetic innervation to the ciliary muscle in the development and correction of refractive errors.
CLINICAL INFERENCES AND DECISIONS—I. DIAGNOSIS AND BAYES‘ THEOREM
Authors: Aspinall P. , Hill A. R.
Published: December 2007

Abstract Clinical decisions are based upon inferences derived from test evidence where data is collected as a means of hypothesis testing. In medicine, the initial expectation of a clinical state is rarely expressed in the classical scientific language of a null hypothesis where alternative outcomes are assumed to be equally probable, because clinical experience reinforces the maxim that common events occur commonly. The collection of test evidence in clinical practice, therefore, is directed towards overturning prior likelihoods for a clinically pathological state which are far from mere chance expectations. The extent to which any test evidence can modify such prior expectations not only depends on its relevance to the clinical state in question (i.e. the hypothesis) but also is largely influenced by the inherent error rates in the test itself. Clinical decision models should reflect these facts. Using examples from the field of ophthalmology, this paper presents a normative model using Bayes' theorem of conditional probabilities which provides a rational framework upon which to base or appraise clinical decisions. Parts II and III of the series will expand this clinical application of decision theory to show how it may be used in the absence of hard test evidence and also where a different emphasis or utility may be placed on false positive or false negative errors.
A SCANNING FOCIMETER TO MEASURE PERIPHERAL LENS POWERS
Authors: Simonet Pierre , Papineau Yves , Gordon Dominique
Published: December 2007

Abstract A special device adapted to a Nikon projection vertexometer permits the power to be measured in the periphery of ophthalmic lenses. The marginal power can be measured with respect to the vertex sphere. Various values of the vertex sphere radius can be obtained with this instrument. The characteristics of this modified focimeter are described in this paper.
THE EFFECT OF REDUCED VIEWING TIME ON COLOUR VISION IN NORMAL SUBJECTS AND THOSE WITH ABNORMAL OCULAR CONDITIONS
Authors: Taylor Steve
Published: December 2007

Abstract The effect of restricting viewing time to 3.75 ms in normal subjects is to produce a tritan‐like colour response on the City University colour vision test. This response pattern is consistent and is repeatable for standard illuminant C at 600 Ix. Supplementary tests suggest that the effect is due to a defect of the blue/yellow opponent system rather than a true tritan defect. The same test when repeated on subjects with amblyopia or retinal pathology provides different results which may aid in the differential diagnosis of some visual disorders.
SCREENING BY OPTOMETRISTS*
Authors: Barnard N. A. Simon
Published: December 2007

Abstract The optometrist is well placed to screen a large proportion of the population for a variety of conditions. Two examples of such screening, for vascular hypertension and learning underachievement, are discussed.
MODELLING THE RESULTS OF THE ORTHOPTIC TREATMENT OF DIVERGENCE EXCESS
Authors: Daum Kent M.
Published: December 2007

Abstract Using data compiled from an earlier study of the results of the orthoptic treatment of divergence excess [Daunt, K. M. Ophthal. Physiol. Opt.4, 15–24 (1984)], a model has been presented regarding the results of the treatment. Provided the calibration sample is representative, the model may be used after an initial examination to predict (he class of success a given subject will eventually be placed in as a result of orthoptic treatment. After treatment with a standard orthoptic regimen, the subjects were classified as being cither totally successful (no abjective or subjective visual difficulties) or partially/not successful. Stepwise discriminate analysis of 15 independent variables for the dependent variable success was used in order to choose the model with the highest coefficient of determination (r) and the best statistical significance. The three variables chosen for the model were the angle of deviation at near and the blur and break values of the negative vergences at near. Using these variable, discriminant analysis was performed on she calibration sample of nine subjects. Each was classified correctly, The use and limitations of the model are briefly discussed.
CLINICAL INFERENCES AND DECISIONS‐II. DECISION TREES, RECEIVER OPERATOR CURVES AND SUBJECTIVE PROBABILITY
Authors: Aspinall P. , Hill A. R.
Published: December 2007

Abstract In patient management, clinical decisions follow a logical sequence which can be formally expressed as a decision tree in which the uncertainties associated with each alternative outcome may be made explicit using Bayes theoreim. Where test data is used in the formulation of a decision, the uncertainey associated with the information it convey may be modified by changing the pass/fail criterion to alter the false negative error rate. Classical procedures based on information theory are described to permit sucha an approach, the clinician must rely on his own past expirence of that of a colleague. Several methods are available for quantifying such experience by estimating subjective probabilities associated with an test result. Two simple methods are described for deriving subjective probabilities for subsequent use within a Bayesian decision model.
THE EFFECT OF RESTRICTED VIEWING TIME ON THE PERFORMANCE OF COLOUR DEFECTIVES USING THE CITY UNIVERSITY COLOUR VISION TEST
Authors: Taylor S. P.
Published: December 2007

Abstract The effect of restricting viewing time to 3.75 ms on the performance of so en red/green colour defectives is studied using the City University Colour Vision Test. One further subject who was screened as colour‐defective but not classified on the City plates was studied in she same way and results for the subject are presented separately. The results arc compared to those for normal observers who exhibit a tritan‐classified defect when viewing time is restricted to 3.75 ms.
TWO SYSTEMS IN THE DETECTION OF VISUAL MOTION *
Authors: Bonnet Claude
Published: December 2007

Abstract Several groups of authors have suggested separate mechanisms for the detection of motion and for the detection of pattern characteristics of the same stimuli (Kulikowski, J. J. and Tolhurst, D. J. (1973) J. Physiol., Lund.232, 149–163; and King‐Smith, P. E. (1978) In Armington, J. C., Krauskopf, J, and Wooten. B. R. (Eds) Visual Psychophysics and Physiology. Academic Press. New York. Their stimuli were generally in the frequency domain. Bonnet (1975) Psychologia18, 35–50; (1977) Perception6, 491–500; and (1982) In Wenheim, A. H., Wagenaar, W. A. and Leibowitz. H. W. (Eds) Tutorials in Motion Perception. Plenum, London I has developed a conceptual model of motion detection in the space–time domain. Two systems are assumed: a movement‐analysing system (MAS) which processes the motion phase of any translation and a displacement‐ analysing system (DAS) which processes the successive stationary components of the Mimultis. These proposed mechanisms are studied in experiments which use three different modes of translation of a single spot: continuous, discrete and stop–go–stop. The first mode should preferentially trigger the MAS, the second mode the DAS, while the stop‐go‐slop mode is a test mode. The results show that for short exposure times (180 ms) the velocity thresholds for the continuous mode are greater than for the other two modes. For these durations, thresholds of the continuous mode are not lowered by the availability of stationary reference points. The effects of luminance on the results with the three modes support the base model.
THE IMPORTANCE OF MOVEMENT TO THE DEVELOPING VISUAL SYSTEM *
Authors: Kennedy Henry , Orban Guy A.
Published: December 2007

Abstract Cais reared under stroboscopic conditions (frequency 2 Hz; duration 0.2 ms), when only a series of “frozen” retinal images is received and the neural channels responsible for movement analysis, are put into competitive disadvantage, show severe deficits in the proportion of direction‐selective cells in areas 17 and 18 and markedly abnormal oplokinetic nystagmus responses.
MACAQUE STRIATE CORTEX: PATTERN, MOVEMENT AND COLOUR PROCESSING *
Authors: Kulikowski J. J. , Vidyasagar T. R.
Published: December 2007

Abstract Simple cells in the primate visual cortex provide a form of generalized, pre‐cognitive mapping of visual scenes. One point in space is represented by several orientation‐specific cells capable of signalling both standing contrast and contrast changes in the scene. The arrangement of simple receptive fields (with a few antagonistic subregions) suggest analysis of scenes both in terms of symmetrical and antisym‐metrical spatial components (i.e. lines and edges) and spatial‐frequency contents. There is no evidence that this analysis is carried out within fixed areas (or patches) since a diversity of receptive field sizes was observed. A chromatic content is probably analysed by a different class of cells with concentric, cone‐opponent receptive fields.
THE PERCEIVED SIZE OF TARGETS IN THE PERIPHERAL AND CENTRAL VISUAL FIELDS
Authors: Bedell Harold E. , Johnson Chris A.
Published: December 2007

Abstract Previously described misperceptions of target size in the peripheral visual field have been conflicting. We found that whether an illuminated peripheral target appears larger or smaller than a foveal target of the same physical size depends upon luminance: in general, dim peripheral targets arc underestimated and bright peripheral targets are overestimated in size. We attribute misestimations of peripheral target size primarily 10 (he optical degradation of peripheral retinal images and propose a qualitative model for how image extent may be determined by the visual system.
A CLINICAL EVALUATION OF THE NIDEK AUTOREFRACTOR
Authors: Wood I. C. J. , Papas E. , Burohardt D. , Hardwick G.
Published: December 2007

Abstract A blind study using the Nidek Autorefractor was carried out on 178 eyes to validate the instrument against conventional refractive techniques. A measure of the NAR's reliability was obtained by repeated measurements of the 178 eyes. The NAR overall performance is compared with current autorefractors.
THE EFFECT OF A YELLOW FILTER ON CONTRAST SENSITIVITY
Authors: Yap Maurice
Published: December 2007

Abstract Most previous studies have found no visual advantage for the use of yellow filters. This study reports the effect of wearing a long‐pass yellow filler on monocular spatial contrast sensitivity under photopic and mesopic conditions. Contrast sensitivity was improved with the yellow filter under photopic conditions but not significantly at most spatial frequencies under mesopic conditions.
FIXATIONAL EYE MOVEMENTS AND AUTOKINESIS IN AMBLYOPES
Authors: Westall Carol A. , Aslin Richard N.
Published: December 2007

Abstract Eye movements were recorded from amblyopic and non‐amblyopic eyes during monocular viewing of a small target on either a patterned or a patternless background. A continuous measure of autokinesis was also obtained. The variance in eye position was greater in amblyopic eyes than in non‐amblyopic eyes. The presence of a patterned background did not reduce the variance in eye position of amblyopic eyes. Autokinesis was greater in amblyopic eyes, but was not correlated with the CM‐movements. A patterned background significantly reduced the magnitude of autokinesis in amblyopic eyes. These results provide support for the hypothesis that a patterned background improves the accuracy of visual direction by reducing spurious extraretinal signals.
VISUAL LOCALIZATION WITH EYE MOVEMENTS: A REVIEW
Authors: Morrison L. C.
Published: December 2007

Abstract This paper reviews and discusses the moil popular theories which have been proposed to account for the stability of the visual environment during eye movements. The subject is discussed chiefly from the stand‐paint of phylogeny rather than its contemporary treatment which attempts to explain neural mechanism by analogy with robotic systems or models. Certain conclusions are formed, and it is postulated that the constancy of egocentric directions following an eye movement is affected by the same mechanism that serves to retain the positional constancy of objects during the operation of the primitive postural reflex.
TWO SPECTACLE LENSES FOR APHAKIA
Authors: Fowler C. W.
Published: December 2007

Abstract Many different designs have been produced for aphakic power spectacle lenses. Two lenses are described which have a common design aim–to produce a lens of large uncut diameter but reasonable cosmetic appearance and weight. These lenses both utilize a continuous aspheric surface on the front surface, which enables them to have a stabilised central power zone and a near piano peripheral flange, but without the disadvantages of the traditional lenticular construction.
CHROMATIC ABERRATION OF THE VERTEBRATE LENS
Authors: Kreuzer R. O. , Sivak J. G.
Published: December 2007

Abstract— A split‐laser technique employing red and blue lasers was used for direct measurement of longitudinal chromatic aberration of excised lenses from a spectrum of vertebrates (fish, amphibians, birds and mammals). The chromatic aberration (442–633 nm) of lenses of most species amounts to a relatively constant 4.6% of equivalent focal length. Dog lenses show somewhat larger amounts (5.7%) while duck and rock bass lenses show less wavelength variation in focal length (3.42–2.70%). In general, chromatic aberration varies little with lens eccentricity, although this point requires further study with more attention to paraxial measurements.
AN ANALYSIS OF VISUAL PERFORMANCE WITH SOFT CONTACT LENS AND SPECTACLE CORRECTION
Authors: Tomlinson Alan , Mann Greg
Published: December 2007

Abstract— This study compares, under controlled conditions and by rigorous statistical analysis, the contrast sensitivity function (CSF) measured with soft‐lens and spectacle correction, attempting to resolve the conflicting reports in the literature. Ten non‐astigmatic ametropic subjects had the CSF measured at eight spatial frequencies with the two types of visual correction. Analysis of variance revealed statistically significant effects for subjects, stimuli and type of visual correction, statistically superior performance being obtained with soft lenses. However, the actual difference in the CSF for the two forms of correction was small (0.14 log units) and not clinically significant. Comparison of the average CSF for the three highest and lowest spatial frequencies tested revealed a significant advantage in using higher spatial frequencies in the determination of statistical differences in the CSF obtained with different types of visual correction.
SOME STATISTICAL CONCEPTS IN THE ANALYSIS OF VISION AND VISUAL ACUITY
Authors: Wild J. M. , Hussey M. K.
Published: December 2007

Abstract— As conventionally recorded, visual acuity data constitute an ordinal scale of measurement. An investigation of four different clinical samples shows that visual acuity is not normally distributed amongst these populations. Furthermore, acuity is often measured on charts which, by the inherent restriction of the stimulus size, have the effect of truncating the upper limit of the scale producing, in statistical terms, an incomplete distribution. The distribution of acuity for each sample is found to be adequately described in terms of the equation: F(x) =Axα(T‐x)β, where F(x) is the cumulative distribution of the statistical population, T is the truncation level (known), x is the Snellen decimal acuity (known) and A, α and β are parameters. Alternative analytical procedures based upon this model, which overcome these limitations, are discussed.
THE INFLUENCE OF ADAPTING VELOCITY AND LUMINANCE ON THE MOVEMENT AFTER‐EFFECT
Authors: Buckingham Terry , Freier Bronwyn
Published: December 2007

Abstract— The response of movement‐sensitive mechanisms to both velocity and luminance may be investigated by means of the movement after‐effect (MAE). A high contrast (98%) drifting grating having a spatial frequency of Ic deg‐1 was used with four adapting velocities of 0.90, 2.87, 4.70 and 7.55 deg see‐1 to confirm their significant effect on initial MAE velocity (F= 29.83, P < 0.01) and duration (F= 12.36, P < 0.01). Four mean luminance levels of 4.5, 12.6, 42.9 and 126 cd m‐2, spanning 1.5 log units of illumination, demonstrate its subtle effect on both initial MAE velocity (F= 4.11, P < 0.01) and duration (F= 3.00, P < 0.05). It is argued that adaptation of movement‐sensitive mechanisms is more accurately reflected by the initial MAE velocity than its duration. The tracking technique which was employed, whilst accurate at low velocities, progressively underestimates the MAE velocity with increasing velocity. With a velocity of 1.2 deg sec‐1 the under‐estimate is 12%, rising to 23% at 2 deg sec‐1. The tracking procedure, however, remains a reliable technique for assessing low velocity MAEs.