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At least 1,045 records · Page 58Linked to original sources

PubMed2006

Myopia, axial length, and OCT characteristics of the macula in Singaporean children.

PURPOSE: The purpose of this study was to evaluate the associations between macular volume and thickness, as assessed by optic coherence tomography (OCT), with refraction and axial length (AL) in children. METHODS: A total of 104 Chinese school children (51 girls and 53 boys) 11 to 12 years of age were randomly selected from one school during the 2005 examination in the Singapore Cohort Study of the Risk Factors for Myopia (SCORM). Cycloplegic autorefraction was performed to obtain refraction (defined as spherical equivalent [SE]) and ultrasound biometry performed to obtain the AL. Macular volume and thickness were then measured (StratusOCT3; Carl Zeiss Meditec, Dublin, CA). RESULTS: Children with moderate myopia (SE at least -3.0 D) tended to have smaller total macular volume and thinner quadrant-specific macular thickness (except in the inferior and superior inner quadrants), followed by children with low myopia (-0.5 -0.5 D). Total macular volume was positively associated with SE (beta=1.58, 95% CI, 0.84 to 2.32, standardized beta=0.14, P<0.001) and negatively associated with AL (beta=-1.20, 95% CI, -1.62 to -0.79, standardized beta=0.45, P<0.001) in multiple linear regression models controlling for age and gender. CONCLUSIONS: In children, increasing axial myopia was associated with reduced macular volume and thickness. These findings suggest that early anatomic changes may be present in the retinas of children with axial myopia.

Anthropometry↗

PubMed2006

Distribution of macular thickness by optical coherence tomography: findings from a population-based study of 6-year-old children.

PURPOSE: To study the distribution of macular thickness by ocular and demographic variables in a population-based study of young children. METHODS: The Sydney Childhood Eye Study examined 1765 6-year-old children from 34 randomly selected Sydney schools during 2003 and 2004 (78.9% response). A comprehensive eye examination included cycloplegic autorefraction and optical biometry. Fast macular thickness scans were performed over a 6-mm diameter central retinal region with optical coherence tomography. Multivariate analyses were performed. Macular thickness is presented on a modified Early Treatment Diabetic Retinopathy Study (ETDRS) macular grid, with outer radii for the central, inner, and outer macular regions being 0.5, 1.5, and 3 mm, respectively. RESULTS: In the study, 1543 children (88.7% of participants; 51.1% boys) had high-quality scan data (mean age, 6.7 years). The mean (SD) minimum foveal thickness was 161.1 (19.4) microm. The thickness of the central, inner, and outer macula was normally distributed, with means (SD) of 193.6 (17.9), 264.3 (15.2), and 236.9 (13.6) microm, respectively. Total macular volume was also normally distributed, with a mean (SD) of 6.9 (0.4) mm(3). The temporal quadrant was thinner than other quadrants for both inner and outer macular regions. The foveal minimum, central, and inner macula was generally significantly thicker in boys than in girls, and in white than in East Asian children. Outer macular thickness showed no significant gender-ethnic differences. Sectoral macular thickness variations were preserved in both gender and ethnic groups. The inner and outer macula, but not the central macula, showed significant thinning with increasing axial length. These corresponding areas were significantly thicker with more hyperopic spherical equivalent refractions. CONCLUSIONS: Macular thickness and volume were normally distributed in this young childhood population. Significant gender and ethnic differences were demonstrated. Axial length and refraction were important ocular biometric determinants of macular thickness.

Anatomy, Cross-Sectional↗

PubMed2006

Altered visual sensitivity in axial high myopia: a local postreceptoral phenomenon?

PURPOSE: The present study investigated retinal integrity in high myopia using spatial psychophysical tasks. METHODS: Ten axial high myopes (-8.5 to -11.5 D) and 10 age-matched control subjects (+/-1.0 D) were recruited. All participants underwent clinical examination and ocular biometry and demonstrated no visible macular disease with visual acuities better than 6/12. Foveal summation thresholds were determined for white and S-cone-isolating spots of various diameters up to 5.4 degrees and spatial contrast sensitivity to luminance sine wave gratings (0.5-9.7 cyc/deg). Data were analyzed after correction for the magnification induced by eye size and correcting lens power. RESULTS: Spatial summation for both white and S-cone-isolating spots showed a generalized loss of sensitivity at all spot sizes in myopes relative to control subjects (P = 0.01). Critical areas at maximum summation were significantly larger in myopes, for S-cone isolating spots only, after image size correction (P = 0.048). Sensitivity at maximum summation correlated negatively with vitreous chamber depth for both targets (P = 0.005). Sensitivities for S-cone and luminance spots also correlated (P < 0.001), indicating widespread dysfunction. Myopes displayed contrast sensitivity losses at high spatial frequencies (P </= 0.006) with a normal peak contrast sensitivity. CONCLUSIONS: These data can be interpreted to indicate that highly myopic eyes have either (1) a reduction in the number of receptors and/or a reduction in their sensitivity or, (2) a reduction in the sensitivity of postreceptoral processes. The presence of normal contrast sensitivity at low spatial frequencies indicates dysfunction at a postreceptoral level in high myopes.

Adolescent↗

PubMed2006

Prevalence of blindness and visual impairment in Pakistan: the Pakistan National Blindness and Visual Impairment Survey.

PURPOSE: To determine the prevalence of blindness and visual impairment in adults aged 30 years and older in Pakistan and to assess socio-demographic risk factors. METHODS: Multistage, stratified (rural/urban), cluster random sampling, with probability proportional-to-size procedures, was used to select a nationally representative, cross-sectional sample of adults 30 years of age or older. Each subject was interviewed; had visual acuity measured (logMAR; logarithm of the minimum angle of resolution); and underwent autorefraction, biometry, and fundus-optic disc examination. Those with less than 6/12 acuity in either eye underwent a detailed ophthalmic examination, including corrected distance visual acuity measurement and dilated ophthalmoscopy. RESULTS: A nationally representative sample of 16,507 adults (95.5% of those enumerated) was examined. The age- and gender-standardized prevalence of blindness was 2.7% (95% confidence interval [CI], 2.4%-2.9%). It has been estimated that there are 1,140,000 (962,000-1,330,000) blind adults in Pakistan (2003 statistics). Blindness prevalence varied throughout the country, being highest in the provinces of Punjab and Baluchistan and lowest in the North West Frontier Province. Rural areas had a higher prevalence of blindness than did urban areas (3.8% vs. 2.5%, P < 0.001). Increasing age and being female were significantly associated with presenting visual acuity of <6/60 (odds ratio [OR], 2.5; 95% CI, 2.3-2.7 and 1.3; 95% CI, 1.1-1.5, respectively). Educational status was also associated with presenting visual acuity of <6/60. Subjects who had attended primary school were 60% (P < 0.001) less likely to have acuity of <6/60 than were subjects who had never been to school. CONCLUSIONS: This comprehensive survey provides reliable estimates of the prevalence of visual impairment and blindness in Pakistan. A significant excess of visual impairment was found among the elderly and the uneducated. After adjustment for age differences, women were found to have a significant excess of severe visual impairment and blindness. Regional variations in the prevalence of blindness were also identified.

Adult↗

PubMed1983

Deinstitutionalization: the data demythologized.

Many past studies of data on deinstitutionalization have used an overly simplistic and often misleading approach, which has led to a number of "myths" of deinstitutionalization. The authors present data on the changing mental health service system collected by the Division of Biometry and Epidemiology of the National Institute of Mental Health, and they analyze the data to reveal trends that disprove a number of the commonly accepted myths. Through their analysis they show that outpatient care has not replaced inpatient care, that public institutions, particularly state mental hospitals, have not been replaced by community-based facilities, and that private resources have not replaced public ones as the bearer of the cost of caring for the mentally ill. They conclude that the availability and quality of mental health services and the effect of these services on patients and their communities are difficult issues for future research.

Community Mental Health Services↗

PubMed2004

Common carotid artery remodeling studied by sonomorphological criteria.

BACKGROUND AND PURPOSE: Only a few attempts have been made to establish the impact of critical intima-media thickness (IMT) on narrowing of the lumen of the common carotid artery (CCA). In the present study, sonomorphological criteria have been used to assess how intima-media thickening in the CCA may influence the artery geometry. METHODS: High-resolution ultrasonography was employed in 233 patients (466 arteries) to quantify the selected parameters of CCA biometry: IMT, arterial lumen diameter (LD), interadventitial diameter (IAD), and outer artery diameter (OAD). RESULTS: With an increase of CCA IMT up to the critical point of 1.2 mm, the LD showed parallel compensatory increases. Above the inflection point of 1.3 mm, the lumen became progressively narrower proportionally to the increasing IMT. CONCLUSION: There are limits to the compensatory enlargement of the CCA lumen. Above the inflection point of CCA IMT of 1.3 mm, the artery lumen becomes progressively narrower with increasing IMT.

Carotid Artery Diseases↗

PubMed2006

Comparison of Venae Sectio vs. modified Seldinger Technique for totally implantable access ports; Portas-trial [ISRCTN:52368201].

BACKGROUND: The insertion of a Totally Implantable Access Port (TIAP) is a routinely employed technique in patients who need a safe and permanent venous access. The number of TIAP implantations is increasing constantly mainly due to advanced treatment options for malignant diseases. Therefore it is important to identify the implantation technique which has the optimal benefit/risk ratio for the patient. STUDY DESIGN: A single-centre, randomized, controlled superiority trial to compare two different TIAP implantation techniques. SAMPLE SIZE: 160 patients will be included and randomized intra-operatively. ELIGIBILITY CRITERIA: Age equal or older than 18 years, patients scheduled for primary elective implantation of a TIAP in local anaesthesia and a signed informed consent. Primary endpoint: Primary success rate of the randomized technique. INTERVENTION: Venae Sectio in combination with the Seldinger Technique (guide wire and a peel away sheath) will be used to place a TIAP. Reference treatment: Conventional Venae Sectio will be used with a direct insertion of the TIAP without guide wire or peel away sheath. Duration of study: Approximately 20 months. ORGANISATION/RESPONSIBILITY: The trial will be conducted in compliance with the protocol and in accordance with the moral, ethical, and scientific principles governing clinical research as set out in the Declaration of Helsinki (1989) and Good Clinical Practice (GCP). The trial will also be carried out in keeping with local and regulatory requirements. The Klinisches Studienzentrum Chirurgie (KSC)--Centre of Clinical Trials in Surgery at the Department of Surgery, University Hospital Heidelberg is responsible for planning and conduction of the trial. Documentation of patient's data will be accomplished via electronical Case Report Files (eCRF) with MACRO-Software by the KSC. Randomization, data management, monitoring and biometry are provided by the independent Koordinierungszentrum für Klinische Studien (KKS)--Coordination Centre for Clinical Trails at the University of Heidelberg.

Journal Article↗

PubMed2005

The influence of cigarette smoking on antenatal growth, birth size, and the insulin-like growth factor axis.

BACKGROUND: Maternal smoking during pregnancy is associated with a reduction in birth size. Very few studies have collated changes in fetal biometry, neonatal anthropometry, biochemical factors involved in fetal growth, and measures of uterine and umbilical blood flow. METHODS: We related smoking status in 1650 low-risk, singleton Caucasian pregnancies delivering at term to measures of fetal growth, uterine and umbilical artery blood flow, placental appearance, birth size, and cord concentrations of IGF-I and -II and IGF binding protein (IGFBP)-3. RESULTS: Mothers who smoked in pregnancy were younger (P < 0.001) and shorter (P = 0.03) and from lower socioeconomic groups (P < 0.001). Mean umbilical artery blood flow at 20 wk gestation was not associated with smoking status but was significantly higher in smokers at 30 wk (P = 0.006). Uterine artery blood flow was unaffected. Smoking was associated with an increase in the percentage of abnormal placentas in a dose-dependent manner and with a 3.1-fold increased risk (odds ratio 3.1, 95% confidence interval 1.3-7.6) of abnormal umbilical artery blood flow (P = 0.009). Smoking was associated with a reduction in fetal femur length (P = 0.005) and abdominal circumference as well as birth weight, length, and head circumference but not skinfold thickness. Cord plasma concentrations of IGF-I and IGFBP-3 were lower in the babies of mothers who had smoked (P = 0.02 and P = 0.01, respectively). CONCLUSION: We concluded that maternal smoking is associated with an altered placental appearance on ultrasonography, increased umbilical artery blood flow resistance, and a reduction in longitudinal and intraabdominal organ growth. Circulating concentrations of IGF-I and IGFBP-3 along with measures of birth size but not markers of body fat are reduced, suggesting smoking results in a reduction in organ size and function.

Adult↗

PubMed1981

Comprehensive hearing aid program within an ear, nose, and throat office.

Hearing aid dispensing within an otolaryngological/audiological clinic is a well accepted fact, and offers total hearing care in a professional setting. The effectiveness of such a program as to wearing habits and acceptance of services rendered, to my knowledge, has not been studied. This paper discussed data obtained from a questionnaire sent out to 1100 hearing aid patients. The questionnaire was designed to study satisfaction with clinic services and costs, acceptance and adjustment, communication abilities and wearing habits. Statistical analysis was performed by the Department of Biometry at LSU Shreveport. The information received is valuable in determining when hearing aids are most helpful and least helpful and brings out some factors which should influence one in determining who should and should not be fitted with amplification.

Adolescent↗

PubMed1998

[Construction of a model eye for simulation of Purkinje reflections for determining the radii of curvature and the position of the crystalline lens].

UNLABELLED: Specular reflections at the optical interfaces of the eye, the Purkinje reflections, are used in physiologic optics and ophthalmology for biometric measurements. To date, there is no standard in the measurement of crystalline lens radii of curvature and position. To that end model eyes were designed. MATERIALS AND METHODS: The most important goal was to simulate the Purkinje reflections I, III, and IV, in the human eye as realistically as possible. The casing of the model eye was made of brass; the optical components were made from contact lens material. RESULTS: Several variants of components were manufactured to reproduce the range of variations in human eyes. By combining different components it was possible to vary the radii of curvature of the cornea and of the crystalline lens, axial separations, crystalline lens rotations and decentrations independently and reproducibly. First applications included devices for biometry of the crystalline lens (phacometry), validation of methods for eye alignment measurement, and refractometry. CONCLUSIONS: The properties of the specular reflections of the model eye are very close to the target values in human eyes. One of the advantages of the model eye is the compact design. This model eye is the first measuring standard for phakometry.

Anthropometry↗

PubMed2000

Is statural growth predictable in utero? Follow-up from the second trimester of gestation to the 8th year of life.

BACKGROUND: It is well known that birth weight is related to later childhood growth and adult height. It can therefore be hypothesized that this relationship exists also for fetal size before birth. OBJECTIVE: To verify whether a child's final height can be predicted by sonographic biometry in utero. SUBJECTS: We evaluated in 116 healthy children both ultrasound measurements in utero and postnatal measurements at a mean age of 6.0 +/- 1.4 years. METHODS: The following fetal ultrasound measurements were obtained: crown-rump length in the first trimester; biparietal diameter, head circumference and femur length in the second and third trimester. RESULTS: Midparental height of the children was correlated both with crown-rump length in the first trimester and with femur length (FL) in the second and third trimester. Predicted adult height was correlated both with FL in the second and third trimester, while present height of the child was correlated with FL only at the third trimester. CONCLUSIONS: FL showed a close relationship with postnatal measurements. For the extreme values of FL, it seems possible to make quite an accurate prediction of the limits of future height. We can reasonably speculate, therefore, that the basis for the future growth of the child can be found in utero.

Abdomen↗

PubMed2001

Antepartal assessment of IUGR fetuses.

Intrauterine growth restriction (IUGR) should be defined on the basis of a prenatally recognized defective growth compared to that expected for this fetus. This condition is encountered in 10-15% of the pregnancies and the perinatal outcome is impaired mainly as a consequence of fetal hypoxemia that is present in 30% of IUGR fetuses. In order to allow for proper management, the IUGR should be recognized prenatally and the method of choice for this purpose is ultrasound fetal biometry. After the identification of IUGR, 2nd level tests should be performed in order to assess the fetal oxygenation conditions. The validity of Doppler investigation on fetal and umbilical vessels is discussed, and the importance of using computer assisted cardiotocography instead of traditional eye ball evaluation of the non-stress test is emphasized.

Cardiotocography↗

PubMed2003

Monitoring the IUGR fetus.

Monitoring of the intrauterine growth retarded fetus in order to improve fetal outcome and define precisely the timing of delivery, when necessary, is based on the study of changes in vital functions observable in cases of hypoxemia. It is easy to believe that ultrasound equipment with Doppler facilities is present in the majority if not in all gynecological units. Cardiotocography is also widely used and the addition of a computerized evaluation system is not expensive and therefore should be available when facing high risk pregnancies such as intrauterine growth retarded cases. IUGR can be recognized through the use of ultrasound fetal biometry and clinical examination of maternal conditions in order to assess fetal conditions. If the above technologies are available further action, such as fetal Doppler study of fetal vessels and cardiotocography, can then be undertaken. In this paper, we will be discussing the issue of monitoring the fetus for fetal well-being, particularly in cases of intrauterine growth retarded fetuses.

Female↗

PubMed2004

Fetal weight estimation in diabetic pregnancies and suspected fetal macrosomia.

OBJECTIVE: To review the literature on the accuracy of sonographic estimated fetal weight (EFW) in diabetic pregnancies, specifically on its role in the prediction and clinical management of fetal macrosomia. METHODS: An English language literature search of Medline listings was performed to review the recently published data on sonographic fetal weight estimation in diabetic pregnancies and suspected fetal macrosomia. RESULTS: Ultrasound biometry used to detect macrosomia is characterized by low sensitivity, low positive predictive value, and high negative predictive value. Serial sonographic measurements and the use of additional examiners can increase the positive predictive value. Regardless of the formula used, the accuracy of the sonographic estimate decreases with increasing birth weight. Three-dimensional ultrasound and magnetic resonance imaging techniques are still investigational. To date, none of the management algorithms developed for selective interventions that are based on the sonographic EFW have demonstrated any efficacy in reducing the incidence of either shoulder dystocia or brachial plexus injury. CONCLUSIONS: The true value of ultrasonography in the management of fetal macrosomia may be its ability to rule out the diagnosis. Ultrasound-derived fetal weight estimates alone are not sufficient grounds for deciding the route of delivery. To assess the risk of macrosomia, other known risk factors should also be taken into account. To determine the mode of delivery, the clinical fetal weight estimate, subjective maternal weight estimate, and clinical assessment of pelvic capacity should be added to the sonographic fetal weight estimate, with consideration of the risk factors for macrosomia.

Birth Weight↗

PubMed1997

Predictive value of a single CTG, ultrasound and Doppler examination to diagnose acute and chronic placental insufficiency in multiple pregnancies.

A non-stress test, an ultrasound biometry (biparietal and abdominal diameter) and a Doppler sonography blood flow measurement (fetal descending aorta, umbilical artery and fetal middle cerebral artery) were performed in the third trimester of 130 multiple pregnancies. These three methods were compared in terms of their prognostic value for fetal growth retardation (81 from 263 children; defined as weight at birth < 10 percentile) and a pathological "fetal outcome" (76 from 263 children, defined as 5-min-Apgar < 8, umbilical artery-pH < 7.20 and transfer to neonatal intensive care unit). Fetal growth retardation could best be predicted by means of the Doppler results for all three blood vessels ("total Doppler result") (sensitivity of 75.9%). Doppler results for all three blood vessels showed the best result in predicting a pathological "fetal outcome"; the sensitivity was 60.3%. The biometric examinations with ultrasound and the non-stress test produced worse results compared to Doppler sonography. Doppler velocimetry of only one blood vessel showed worse results compared to Doppler velocimetry of more than one blood vessel. Doppler sonography should be performed as a routine test for all multiple pregnancies. More intensive pregnancy surveillance is urgently recommended with pathological findings.

Acute Disease↗

PubMed1998

The fetal outcome in pregnancies with isolated reduced amniotic fluid volume in the third trimester.

Our aim was to assess the outcome of pregnancies where oligohydramnios, defined by a published gestational reference range for amniotic fluid index, was the only abnormal finding at third trimester scan, and all other ultrasound parameters including biometry were within normal limits at initial scan. A retrospective case-control study was performed at The Liverpool Maternity Hospital. 103 pregnancies with reduced amniotic fluid index in the third trimester and apparently normal fetal growth profile ultrasonographically were identified from ultrasound reports throughout 1993. Pregnancies in the third trimester with normal amniotic fluid index on index scan were also identified from these reports and 103 were matched for parity, gestational age at delivery, mode of onset of labour, presentation at labour and medical conditions. Exclusion criteria were ruptured membranes, fetal abnormalities, estimated fetal weight below the fifth centile at index scan and multiple pregnancies. The outcome criteria were birthweight, Apgar scores at delivery, induction and emergency delivery for fetal reasons and admission to Neonatal Intensive Care Unit. Statistical analysis was performed by Fisher's exact test and Gart's odds ratio. Compared with controls, pregnancies in the reduced liquor group had a higher number of babies below the 5th centile (odds ratio 5.2, 95% confidence interval 1.6 to 22), a higher risk of induction for fetal reasons (odds ratio 34.4, 95% confidence interval 5.35 to 1425.5) and admission to Neonatal Intensive Care Unit (odds ratio 9.77, 95% confidence interval 1.3 to 432). Any observed difference in the need for emergency delivery due to fetal reasons was not clinically significant (odds ratio 2.16, 95% confidence interval 0.77 to 6.6) The definition used for oligohydramnios used in this study appears to identify a group of babies with a fourfold risk of low birthweight and a high risk of admission to the Neonatal Intensive Care Unit and induction of labour for fetal reasons. This would suggest that pregnancies with isolated oligohydramnios require some form of fetal monitoring and further prospective studies are required to determine the most appropriate method.

Apgar Score↗

PubMed2004

How to understand a complex reality: statistical issues in microarray experiments. Interview by Nadine Lemmens.

Dr Mansmann is Deputy Director of the biostatistic unit of the Institute of Medical Biometry and Informatics at the University of Heidelberg Medical School, Germany. He is head of the working group in quantitative methods in molecular medicine. His research interests are prognostic models for cancer patients and establishing methodological standards for reproducible research in molecular medicine. As a statistician, he is involved in research on the use of Bayesian methodology for complex stochastic systems.

Humans↗

PubMed2004

Ultrasound in the diagnosis and management of intrauterine growth retardation.

OBJECTIVE: To evaluate the value of ultrasound in the diagnosis and management strategies of intrauterine growth retardation. DESIGN: A descriptive study. PLACE AND DURATION OF STUDY: Radiology Department, Aga Khan University Hospital, Karachi, from April 1998 to August 1999. PATIENTS AND METHODS: The study population comprised of 206 subjects evaluated for suspected intrauterine growth retardation. Grey scale as well as Doppler ultrasound findings were evaluated and compared against post-natal outcome. RESULTS: One hundred and eight out of 206 subjects showed positive imaging results with 40 false positive and 20 false negative subjects. The sensitivity, specificity, positive predictive and negative predictive values were 77.8%, 66.1%, 55.6%, and 45.1% respectively. Forty subjects showed false positive results on imaging (low biophysical profile score and Grey scale biometry discrepancy) while 20 of the subjects showed false negative results (normal on US imaging) when compared with postnatal neonatal body weight criteria. Twenty-two subjects had oligohydramnios with amniotic fluid index below 5 percentile for their respective gestational ages (20%) out of 108. CONCLUSION: Obstetric and Doppler ultrasound is an accurate method for diagnosis and management of fetal growth retardation.

Adolescent↗