The environment can explain differences in adolescents' daily physical activity levels living in a deprived urban area: cross-sectional study using accelerometry, GPS, and focus groups.

Background: Evidence suggests that many contemporary urban environments do not support healthy lifestyle choices and are implicated in the obesity pandemic. Middlesbrough, in the northeast of England is one such environment and a prime target for investigation.

Methods: To measure physical activity (PA) levels in a sample of 28 adolescents (aged 11 to 14 years) and describe the environmental context of their activity and explore where they are most and least active over a 7-day period, accelerometry and Global Positioning System (GPS) technology were used.

Effect of reducing total fat intake on body weight: systematic review and meta-analysis of randomised controlled trials and cohort studies.

Objective: To investigate the relation between total fat intake and body weight in adults and children.

Design: Systematic review and meta-analysis of randomised controlled trials and cohort studies.

Data Sources: Medline, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials to June 2010.

Evidence-based recommendations for the development of obesity prevention programs targeted at preschool children.

The ToyBox intervention was developed using an evidence-based approach, using the findings of four reviews. These reviews included three critical and narrative reviews of educational strategies and psychological approaches explaining young children's acquisition and formation of energy-balance related behaviours, and the management of these behaviours, and also a systematic review of behavioural models underpinning school-based interventions in preschool and school settings for the prevention of obesity in children aged 4-6 years. This paper summarises and translates the findings from these reviews into practical evidence based recommendations for researchers and policy-makers to consider when developing and implementing interventions for the prevention of overweight and obesity in young (aged 4-6 years) children.

Critical narrative review to identify educational strategies promoting physical activity in preschool.

The aim of this narrative review is critically to evaluate educational strategies promoting physical activity that are used in the preschool setting in the context of obesity prevention programmes. Literature search was conducted between April and August 2010 in English and German databases (PubMED, PsychINFO, PSYNDEX, ERIC, FIS Bildung). Outcomes considered were time and intensity of physical activity, motor skills or measures of body composition.

Identifying effective behavioural models and behaviour change strategies underpinning preschool- and school-based obesity prevention interventions aimed at 4-6-year-olds: a systematic review.

The aim of this comprehensive systematic review was to identify the most effective behavioural models and behaviour change strategies, underpinning preschool- and school-based interventions aimed at preventing obesity in 4-6-year-olds. Searching was conducted from April 1995 to April 2010 using MEDLINE, EMBASE, CINAHL, PsycINFO and The Cochrane Library. Epidemiological studies relevant to the research question with controlled assignment of participants were included in the review, if they had follow-up periods of 6 months or longer.

A narrative review of psychological and educational strategies applied to young children's eating behaviours aimed at reducing obesity risk.

Strategies to reduce risk of obesity by influencing preschool children's eating behaviour are reviewed. The studies are placed in the context of relevant psychological processes, including inherited and acquired preferences, and behavioural traits, such as food neophobia, 'enjoyment of food' and 'satiety responsiveness'. These are important influences on how children respond to feeding practices, as well as predictors of obesity risk.

Clinician versus potential acuity test predictions of visual outcome after cataract surgery.

Background: The aim of this study was to compare the ability of potential vision tests and clinical judgement to predict postoperative visual acuity after uneventful cataract surgery.

Methods: Sixty-two subjects (median, 74.5 years) were included in the study.

Precision of orbscan II assessment of anterior corneal curvature and asphericity.

Purpose: To determine the number of measurements required to produce a representative mean result for corneal apical radius and asphericity and to examine the repeatability of this mean result.

Methods: The Bausch & Lomb Orbscan II corneal topographer was used to take 10 measurements of right eyes of 20 normal individuals. These were used to determine the number of measurements required to obtain a representative result.

Cornea measurement comparison with Orbscan II and EyeSys videokeratoscope.

Purpose: To compare the performance of the Orbscan II topographer with a videokeratoscope for a set of tilted test buttons with known aspheric surface profile characteristics, and for a series of measurements made on normal human corneas.

Methods: Measurements of apical radius and p-value were obtained from 12 aspheric test surfaces using the Orbscan II, the EyeSys videokeratoscope, and Form Talysurf analysis. Measurements from the corneas of 18 human subjects were assessed by comparison with data from the EyeSys videokeratoscope.

Predictions of postoperative visual outcome in subjects with cataract: a preoperative and postoperative study.

Aim: To assess the ability of critical flicker frequency (CFF) and optimal reading speed (ORS) to predict the potential vision in patients with cataract with and without ocular comorbidity.

Methods: The two novel tests were compared with two well established potential vision tests (PVTs), the potential acuity meter (PAM) and the laser interferometer (LI). Measurements were made preoperatively in 1 eye of 88 subjects using the battery of 4 PVTs.

Capabilities of potential vision test measurements: clinical evaluation in the presence of cataract or macular disease.

Purpose: To determine the usefulness of a battery of potential vision tests (PVTs) including potential acuity meter (PAM), laser interferometer (LI), critical flicker/fusion frequency (CFF), superilluminated pinhole at distance (SPH(d)) and near (SPH(n)), and optimal reading speed (ORS) by their independence of the effects of cataracts and sensitivity to macular disease (MD).

Setting: Department of Optometry, University of Bradford, Bradford and Leeds General Infirmary, Leeds, United Kingdom.

Methods: Potential vision test measurements were determined in 76 patients with age-related cataract and no other eye disease, 52 patients with MD and clear ocular media, and 28 patients with normal, healthy eyes.

Clinical performance of polynomial lenses versus tri-curve lenses. II: ocular responses.

This study, which was a continuation of the previous one, aimed to determine the subjective and objective responses after wearing polynomial and tri-curve rigid gas permeable (RGP) lenses over a period of 6 months. Subjects were divided into two groups, each of which wore either one of these lens designs and 17 of 22 subjects completed the 6-month study. Subjective responses were assessed by a questionnaire while the objective responses including vision, contrast sensitivity, lens fitting and the corneal integrity, corneal thickness and endothelial cell morphology were assessed by the examiner.

Clinical performance of polynomial lenses versus tri-curve lenses. I: initial comfort.

Twenty-two subjects were asked to wear custom-made polynomial back surface design rigid gas permeable (RGP) lenses and conventional tri-curve RGP lenses to compare the initial comfort provided by the two lens designs monocularly and binocularly. Polynomial lenses, based on tri-curve lens fittings, did not provide better initial comfort than tri-curve lenses. The results seem to indicate that an aspheric back surface alone may not play a very important role in the initial comfort of RGP lens wear.

Contact lens back surface specification derived from the EyeSys videokeratoscope.

Rigid corneal lenses were designed for 36 subjects using the software available with the EyeSys Corneal Analysis System 2000 (software version 2.00W) and a program from the textbook 'Contact lens Optics and Lens Design' Both alignment and apical clearance designs were investigated. It was found that the EyeSys lenses produced tear layer thickness and axial edge clearance values that were excessive in some cases, especially for flatter corneas.

Critical flicker frequency as a potential vision technique in the presence of cataracts.

Purpose: Potential vision testing attempts to predict the visual outcome that might be expected as a result of a cataract operation. This report details the clinical utility of critical flicker frequency (CFF) as a potential vision test (PVT).

Methods: CFF thresholds were determined in 31 subjects with age-related idiopathic cataract and no other eye disease, 19 subjects with macular disease (MD) and clear ocular media, and 24 age-matched control subjects.

Development of a critical flicker/fusion frequency test for potential vision testing in media opacities.

Purpose: To determine whether critical flicker/fusion (CFF) thresholds fulfill the criteria for a potential vision test (PVT) by being unaffected by media opacity yet affected by retinal disease.

Methods: CFF thresholds for three different stimulus sizes (0.5, 1.

Verification of aspheric contact lens back surfaces.

Purpose: To suggest a tolerance level for the degree of asphericity of aspheric rigid gas-permeable contact lenses and to find a simple method for its verification.

Methods: Using existing tolerances for the vertex radius, tolerance limits for eccentricity and p values and were calculated. A keratometer-based method and a method based on sag measurements were used to measure the vertex radius and eccentricity of eight concave progressively aspheric surfaces and six concave ellipsoidal surfaces.

The asphericity, curvature and tilt of the human cornea measured using a videokeratoscope.

The EyeSys videokeratoscope (VK) measurements of the principal corneal meridians of 98 subjects already analysed by Douthwaite et al. [Ophthal. Physiol.

Acuity predictions from visually evoked potential to checkerboard pattern reversal stimuli: the effect of reversal rate.

INTRODUCTION: A pattern reversal stimulus (check size 5.5 minutes of arc) was used to elicit the visually evoked potential (VEP). METHODS: The peak to trough amplitude of the VEP wave was measured and compared to subjective visual acuity (Landolt C).

Initial selection of soft contact lenses based on corneal characteristics.

Purpose: To determine apical radius, surface asphericity, and horizontal visible iris diameters (HVID) in normal subjects and to find out which has the greatest influence on the corneal sagittal depth.

Methods: Videokeratoscopic data were analyzed to determine the apical radius and the p-value of the near horizontal principal meridian for 73 right and 77 left eyes. The HVID also were measured.

Application of linear regression to videokeratoscope data for tilted surfaces.

Purpose: To investigate the use of linear regression analysis performed on the tabular data display of the EyeSys videokeratoscope (VK). When a radius squared vs distance squared scatterplot is produced from aspheric surface data the equivalent conic section can be deduced from the intercept and slope of the linear regression line. Non-linear plots are often produced.

Corneal topography by keratometry.

Aims: To investigate the ability of a telecentric keratometer to describe the asphericity and curvature of convex ellipsoidal surfaces and human corneas.

Methods: 22 conicoidal convex surfaces and 30 human corneas were examined by conventional keratometry. Additional keratometric measurements were made when the surface was tilted in the horizontal plane relative to the instrument optical axis.

Corneal shape of Hong Kong-Chinese.

Corneal asphericity (the p-value, p) and apical corneal radius (r0) were calculated for 63 Hong Kong-Chinese (39 male and 24 female), using the Topographic Modeling System (TMS-1). The values of p and r0 in, and between, the two principal meridians were compared, and the effects of refractive error and gender were also investigated. The mean +/- SD r0 and p along the flattest meridian of the right eye were 7.

The EyeSys videokeratoscopic assessment of apical radius and p-value in the normal human cornea.

The EyeSys videokeratoscope was used to assess the corneal topography in 98 subjects. Scatterplots of distance squared versus radius squared were plotted for the near horizontal and near vertical principal meridians of the two eyes. The regression lines allowed calculation of the surface apical radius and the p-value.