bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of high‐speed videokeratoscopy and ultrasound distance sensing for measuring the longitudinal corneal apex movements
Authors: Kowalska Malgorzata A. , Kasprzak Henryk T. , Robert Iskander D. 
Published: April 2009

AbstractTwo different methods to measure binocular longitudinal corneal apex movements were synchronously applied. High‐speed videokeratoscopy at a sampling frequency of 15 Hz and a custom‐designed ultrasound distance sensor at 100 Hz were used for the left and the right eye, respectively. Four healthy subjects participated in the study. Simultaneously, cardiac electric cycle (ECG) was registered for each subject at 100 Hz. Each measurement took 20 s. Subjects were asked to suppress blinking during the measurements. A rigid headrest and a bite‐bar were used to minimize undesirable head movements. Time, frequency and time‐frequency representations of the acquired signals were obtained to establish their temporal and spectral contents. Coherence analysis was used to estimate the correlation between the measured signals. The results showed close correlation between both corneal apex movements and the cardiopulmonary system. Unraveling these relationships could lead to better understanding of interactions between ocular biomechanics and vision. The advantages and disadvantages of the two methods in the context of measuring longitudinal movements of the corneal apex are outlined.
Changes of ocular aberrations with gaze
Authors: Prado P. , Arines J. , Bará S. , Manzanera S. , Mira‐Agudelo A. , Artal P. 
Published: April 2009

AbstractThe dependence of the ocular aberrations on gaze has been studied in three eyes using a fast‐acquisition, Hartmann–Shack wavefront sensor. Although there were some trends in the change of some aberration terms with gaze, the changes of most Zernike coefficients were smaller than their variability at each individual gaze position, due to the combined effects of microfluctuations of accommodation, eye movements, tear film dynamics, and measurement noise. For our particular experimental dataset, the confidence level at which the null hypothesis (i.e. that the aberrations do not change significantly with gaze) can be rejected is very low. Further advances in the study of the dependence of eye aberrations with gaze will require a tighter control of the sources of aberration variability at each individual gaze position.
Comparison of the ocular wavefront aberration between pharmacologically‐induced and stimulus‐driven accommodation
Authors: Plainis S. , Plevridi E. , Pallikaris I. G. 
Published: April 2009

AbstractPurpose:  To compare the ocular wavefront aberration between pharmacologically‐ and stimulus‐driven accommodation in phakic eyes of young subjects.Methods:  The aberration structure of the tested eye when accommodating was measured using the Complete Ophthalmic Analysis System (COAS; AMO WaveFront Sciences, Albuquerque, NM, USA). It was used in conjunction with a purposely‐modified Badal optometer to allow blur‐driven accommodation to be stimulated by a high contrast letter E with a vergence range between +0.84 D and −8.00 D. Pharmacological accommodation was induced with one drop of pilocarpine 4%. Data from six subjects (age range: 23–36 years) with dark irides were collected.Results:  No correlation was found between the maximal levels of accommodative response achieved with an 8 D blur‐driven stimulus and pharmacological stimulation. Pharmacological accommodation varied considerably among subjects: maximum accommodation, achieved within 38–85 min following application of pilocarpine, ranged from 2.7 D to 10.0 D. Furthermore, although the changes of spherical aberation and coma as a function of accommodation were indistinguishable between the two methods for low levels of response, a characteristic break in the pattern of aberration occurred at higher levels of pilocarpine‐induced accommodation. This probably resulted from differences in the time course of biometric changes occuring with the two methods.Conclusion:  Measuring the pilocarpine‐induced accommodative response at only one time point after its application may lead to misleading results. The considerable inter‐individual differences in the time course of drug‐induced accommodative response and its magnitude may lead to overestimation or underestimation of the corresponding amplitude of normal, blur‐driven accommodation. Stimulating accommodation by topical application of pilocarpine is inappropriate for evaluating the efficacy of ‘accommodating’ IOLs.
Myopia and visual acuity impairment: a comparative study of Greek and Bulgarian school children
Authors: Plainis Sotiris , Moschandreas Joanna , Nikolitsa Panagoula , Plevridi Eleani , Giannakopoulou Trisevgeni , Vitanova Vania , Tzatzala Paraskevi , Pallikaris Ioannis G. , Tsilimbaris Miltiadis K. 
Published: April 2009

AbstractPurpose: To compare the proportions of school children with myopia and impaired visual acuity in Greece and Bulgaria.Methods: A sample of 898 children, aged 10–15 years, was selected from two primary and two secondary schools in a Greek city (Heraklion), and one primary and secondary school in a Bulgarian city (Stara Zagora). Five hundred and eighty eight children were Greek (65.5%, mean age 12.5 ± 0.08 years) and 310 Bulgarian (34.5%, age 12.4 ± 0.07 years). VA was assessed with the habitual refractive correction. Refractive error was measured in the absence of cycloplegia using an auto‐refractor.Results: The percentage of children, tested with their habitual refractive correction, with decimal VA <0.5 in at least one eye was 11.7% (95% CI 9.1–14.3%) for Greek and 5.2% (95% CI 2.7–7.6%) for Bulgarian pupils. The percentage of myopic children also differed between the two countries with the proportion with myopic refractive error ≤−0.75 D and decimal VA <0.8 at primary school level being 14.1% and 28.9% in Stara Zagora and Heraklion respectively and 13.0% and 46.9% (95% CI 18.2–29.2%,p < 0.0001) at secondary school level. Among the myopic pupils only 35.8% used corrective spectacles in Stara Zagora, compared to 70.7% of the children in Heraklion. Finally, myopia appeared more prevalent in female adolescents with the effect being statistically significant only for Greek children (55% vs 40% of males,p = 0.015).Conclusions: The increased proportion of myopic children in Heraklion, compared to Stara Zagora, may arise from a number of environmental and socio‐economic factors, which need to be further investigated in order to understand the differences observed among European populations.
Contrast sensitivity based orientation changes in refractive surgery patients
Authors: Tahir Humza J. , Parry Neil R. A. , Brahma Arun , Ikram Khalid , Murray Ian J. 
Published: April 2009

AbstractIt is well known that refractive surgery leads to an increase in higher‐order aberrations. These can cause problems such as glare, starburst and halos in vision, particularly in low light levels when the pupil is large. The overall wavefront aberration of the eye is typically non‐circularly symmetric due to the presence of aberrations such as coma and trefoil. These asymmetries have been shown to induce orientation‐selective effects in grating‐based contrast sensitivity tests. Classically, contrast sensitivity is assumed to be independent of orientation and is measured at only one orientation. Examining more orientations may give a better indicator of visual performance when abnormal amounts of aberration are present. To examine this, contrast sensitivity through a dilated pupil was determined for four orientations of a 12 cycles deg−1 sine wave grating in 12 subjects both before and after refractive surgery. Surgery produced orientation‐selective changes in contrast sensitivity in most patients (9 out of 12, p < 0.05). The correlation between contrast sensitivity and higher‐order aberrations was found to improve when several orientations were tested compared with data from only one orientation (combined orientations, r2 = 0.46, p = 0.007; single orientation r2 = 0.55, p < 0 .05 to r2 = 0.09, p > 0.05). These results indicate that grating orientation is an important factor when investigating the link between visual performance and higher order aberrations.
Analysis of the optical properties of crystalline lenses by point‐diffraction interferometry
Authors: Acosta Eva , Vázquez Daniel , Castillo Luis Rodríguez 
Published: April 2009

AbstractPurpose:  To show the feasibility of modified point‐diffraction interferometry for the qualitative analysis and accurate quantification of phase aberrations of eye lenses in vitro.Method:  Optical aberrations of crystalline lenses in vitro were evaluated by means of a point‐diffraction interferometer modified to increase its dynamic range.Results:  Analysis of the Zernike polynomials, , which contribute significantly to the wavefront aberration of two representative crystalline lenses (a mammalian and a fish lens) is presented. In the mammalian case, the in vitro experiments were performed for pig lenses. It is shown that spherical aberration, astigmatism, coma, and trefoil of different radial orders, n, are the only modes contributing significantly to wavefront aberration, i.e., aberrations with azimuthal frequencies, m, greater that three can be regarded as noise. In the case of fish lenses (sea bream), we show that the technique allows quantification of the deviation from the spherical symmetry which is commonly assumed for teleost fish lenses.Conclusions:  Modified point‐diffraction interferometry is a wavefront‐sensing technique that can be used to accurately analyze phase aberrations in eye lenses and hence evaluate their contribution, in terms of significant aberrations, to the total aberrations of the eye.
Retinal image quality for virtual eyes generated by a statistical model of ocular wavefront aberrations
Authors: Thibos Larry N. 
Published: April 2009

AbstractA statistical model of the aberration structure of normal, well‐corrected eyes was developed previously (Opthal. Physiol. Opt22, 427–433, 2002.) from wavefront aberrations measured for 100 normal eyes (J. Opt. Soc. Am. A.19, 2329–2348, 2002.). The model is capable of generating an unlimited number of wavefront aberration functions for virtual eyes drawn randomly from a multivariate Gaussian distribution of Zernike aberration coefficients. This report provides evidence that monochromatic retinal image quality in virtual eyes, as quantified by 31 different image quality metrics (J. Vis.4, 329–351, 2004.), is representative of human eyes but slightly exaggerates the degradation of the retinal image caused by ocular aberrations. A demonstration program for producing virtual eyes is included as an Appendix to this paper.
The contribution of the fixational eye movements to the variability of the measured ocular aberration
Authors: Arines J. , Pailos E. , Prado P. , Bará S. 
Published: April 2009

AbstractThe purpose of this work is to analyze the contribution of eye movements to the variability of the Zernike coefficients as determined with a Hartmann–Shack aberrometer. In order to isolate this effect we considered static aberrations tied to the eye pupil. We used several eye movements of different magnitude, both synthetic and corresponding to actual series recorded in our laboratory with different subjects. Our results show the relevance of the modal coupling induced by the estimation process and the benefit of correcting eye movements in order to get a better estimate of the ocular aberrations. They also show that eye movements during aberrometric measurements are an important source of apparent wavefront variability.
Damped least‐squares approach for point‐source corneal topography
Authors: Sokurenko Vyacheslav , Molebny Vasyl 
Published: April 2009

AbstractAn optimization algorithm to be used in point‐source corneal topographers is developed for the reconstruction of the topography of aspheric corneal surfaces. It is based on the damped least‐squares technique. The reconstructions obtained with a topographer comprising 48 or 90 point sources for corneas having different forms (spherical, conicoidal, complex) and apical radii (5–16 mm) were simulated numerically. Zernike polynomials up to the seventh radial order were used for the description of the shape of the anterior corneal surface. With no noise, i.e. uncertainty in the position of the image of each object point, it is shown that this approach allows reconstruction of the surface with a root‐mean‐square (RMS) error of <5 × 10−7 μm for the elevation map and 3 × 10−7 diopter for the refraction map. With noise, to get an averaged surface elevation RMS error of <1 μm, or an averaged refraction RMS error of <0.25 diopter, each spot must be located (in the image plane) with an error <1 μm.
Nasal‐temporal differences in cone‐opponency in the near peripheral retina
Authors: Panorgias A. , Parry N. R. A. , McKeefry D. J. , Kulikowski J. J. , Murray I. J. 
Published: April 2009

AbstractThe purpose of this study is to establish whether nasal‐temporal differences in cone photoreceptor distributions are linked to differences in colour matching performance in the two hemi‐fields. Perceived shifts in chromaticity were measured using an asymmetric matching paradigm. They were expressed in terms of hue rotations and relative saturation changes and also in terms of activation levels of L−M or S−(L+M) cone‐opponent channels. Up to 19° eccentricity there was little difference in chromaticity shifts between nasal and temporal retina for either channel. For matches beyond 19° L−M activation is significantly lower in the nasal field and the S−(L+M) channel was equally activated in both fields. The data are consistent with the asymmetric distribution of L‐ and M‐cones in the nasal and temporal retinae.
Macular pigment measurement in clinics: controlling the effect of the ageing media
Authors: Makridaki M. , Carden D. , Murray I. J. 
Published: April 2009

AbstractWe report a series of experiments designed to ensure that Macular Pigment Optical Density (MPOD) measurements obtained with a clinical instrument are not influenced by lens yellowing and ocular media optical density. These effects were determined in six subjects using seven Lee Colour Temperature Correcting filters to simulate changes in the transmittance of the ocular media with age. Calculated simulated age matched the data linking age and optical density reported in the literature, and the MPOD was independent of simulated age. The instrument allows an estimation of MPOD to be made which is based only on a foveal (centre‐only) measurement rather than, as is conventional, making a comparison between foveal and peripheral measurements. We assessed the performance of this facility by comparing the centre‐only estimate of MPOD with that obtained from both central and peripheral measurements in 5616 eyes. The 95% limits of agreement for the two estimates was 0.13 OD units.
Full‐genome nucleotide sequence and analysis of a Chinese swine hepatitis E virus isolate of genotype 4 identified in the Guangxi Zhuang autonomous region: evidence of zoonotic risk from swine to human in South China
Authors: Li Lingjun , Zhu Yonghong , Fu Hongwei , Wei Xianfei , Wang Ling , Liang Jingrui , Ji Yanli , Tang Ronglan , Zhuang Hui 
Published: April 2009

AbstractBackground: Hepatitis E virus (HEV) is one of the leading causes of the enteric‐transmitted acute hepatitis. Many studies have found high identities between human and animal HEV isolates using partial sequence comparison analysis.Aims: To determine and phylogenetically analyse the complete genome of the swGX40 isolate from the Guangxi Zhuang autonomous region.Methods: The overlapping fragments of HEV isolate swGX40 were amplified with reverse transcription‐nested polymerase chain reaction (PCR) and the 5′ and 3′ ends of viral genome were amplified with rapid amplification of cDNA ends. The PCR products were cloned and sequenced. The sequence and phylogenetic analysis of swGX40 were performed.Results: The full genome of the swGX40 strain consisted of 7233 nucleotides, excluding the poly (A) tail of 36 residues. There are three open reading frames (ORFs), encoding 1705, 674 and 114 amino acids (aa) respectively. The full‐genomic sequencing showed that the swGX40 strain shared similarity with all known HEV genotype 1, 2 and 3 isolates by 73.4–76.5% and with an identity of 83.1–91.2% among genotype 4 HEV isolates. The partial ORF2 sequencing (249 nt) showed that swGX40 shared a high nucleotide identity of 94 and 97% with the Chinese human strain LZ‐105 and the Vietnamese human strain HE‐JVN‐1 respectively.Conclusions: The swine isolate swGX40 was closely related to the human isolate LZ‐105, both of which were collected from Liuzhou, the same district in the Guangxi Zhuang autonomous region. This molecular biological evidence strongly supported the zoonosis hypothesis of hepatitis E.
Health Problems and Health Behaviors of Korean Preschoolers Living With Parents and Under Guardianship
Authors: Kim Hee‐Soon , Ham Ok‐Kyung , Lee Chung‐Yul , Lee Tae‐Wha 
Published: April 2009

ABSTRACT
Purpose: A comparative analysis was conducted to identify and compare the health status and behaviors of preschoolers attending daycare centers in South Korea between children living with parents and those under guardianship.Design: The study design was descriptive and correlational.Sample: Data were collected from 152 parents and 85 guardians of preschool children using a structured questionnaire.Results: Of 237 children, 23.9–32.5% were overweight or obese, while 13.8–30.0% were underweight. Boys under guardianship were more likely to be obese. Hand‐foot‐mouth disease and atopic dermatitis were more prevalent among children living with parents, while those under guardianship were less likely to have dentistry visits, more likely to be absent from childcare due to pneumonia, and had significantly fewer health‐related conversations with their guardians. In relation to health behaviors, the frequency of tooth‐brushing and high‐calcium food consumption was significantly lower among children under guardianship than among those living with parents.Conclusion: Compared with children living with parents, those under guardianship were exposed to unfavorable circumstances in terms of health management practices and health behaviors, which implies that the guardians were less interested in health care and dealt inappropriately with the health problems of their foster children.
Workplace Health Promotion Activities of Finnish Occupational Health Nurses
Authors: Naumanen Paula , Liesivuori Jyrki 
Published: April 2009

ABSTRACT
Objective: This study describes workplace centered activities performed by occupational health professionals, as well as difficulties linked to workplace centered activities, cooperation with client workplaces, and participation both in risk assessment and in the development of working environment.Design: The design is a cross‐sectional prevalence study.Sample: The questionnaires were sent to 250 occupational health professionals, of whom 176 (70%) returned the completed forms and of whom 99% were nurses.Measurements: Their activities, difficulties, cooperation, and participation in risk assessment and development of safe and healthy working conditions.Analytic strategy: The data were analyzed by using frequencies, means, 1‐way ANOVA, and the Kruskal‐Wallis test.Results: Workplace focused activity hours were mainly spent on risk assessment and counseling. One workplace visit took approximately 4 hr. The greatest difficulties were encountered with participation in development projects and in monitoring the effectiveness of improvement activities, especially in health care centers. Occupational health nurses cooperated with client enterprises and participated in risk assessment more often than the other occupational health professionals. Also workplace representatives participated actively in risk assessment. The most difficult modules were considered to be the risk assessment of chemicals, biological factors, and perceived stress, this being especially so in health care centers.Conclusions: It is essential that occupational health professionals visit more often in their client enterprises and improve their skills in preventing harms caused by chemical and biological factors, and perceived stress.
Effects of a Cognition‐Oriented Breast Self‐Examination Intervention for Korean Women and Their Spouses
Authors: Park SoMi , Song Hee‐Young , Hur Hea Kung , Kim GiYon 
Published: April 2009

ABSTRACT
Objective: This study evaluated the effectiveness of a cognition‐oriented breast self‐examination (BSE) intervention program that is based on the Transtheoretical Model and reflects individual characteristics according to BSE stage among Korean women and their spouses.Design: A time‐series nonequivalent control group design was used.Sample and Measurement: Twenty‐four couples in each of 2 groups completed a preintervention test and were evaluated 1, 3, and 6 months later for their knowledge of breast cancer and BSE, spousal encouragement for BSE, perceived confidence in BSE methods, change in BSE stage, and perceived benefits and barriers to BSE. The intervention involved husbands as well as women, and consisted of lectures on breast cancer and BSE, demonstrations and practice with models while being videotaped, and feedback.Results: There were significant differences between the control and experimental groups for all variables. Change of BSE stage in experimental group showed significantly advancement over time.Conclusions: This intervention program was effective in promoting regular BSE practice and in enhancing confidence in BSE. The intervention also raised awareness among husbands of the importance of breast health for their wives. Educational interventions for breast cancer prevention should be specified to an individual's stage of BSE.
Social Support and Cervical and Breast Cancer Screening in Argentinean Women From a Rural Population
Authors: Gamarra Carmen Justina , Paz Elisabete Pimenta Araújo , Griep Rosane Harter 
Published: April 2009

ABSTRACT Objective:To examine whether emotional social support influences the use of 3 cancer screening tests in females.Design:Cross‐sectional study.Sample:Data were collected via a household survey of a random sample of 200 Argentinean women.Measurements:The questionnaire included self‐reported data about the cancer screening tests (Papanicolaou [Pap] test for cervical cancer, breast self‐examination, and clinical examination for breast cancer), and socioeconomic background information. Social support was measured by the Duke‐UNC‐11 questionnaire.Analysis:Logistic models were used to investigate the association between social support and cancer screening tests.Results:Emotional social support was associated with having participated in Pap screening within 3 years before this study, but a link between social support and self or clinical breast examination was not supported.Conclusion:Emotional social support may play a role in early cervical cancer detection among Argentinean females, specifically by encouraging performance of the Pap test. The educational practices accomplished by nurses should include actions that involve the family and community; therefore, emphasizing the importance of social ties on health and promoting interactions between target women and existent social groups in the community.