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1.
Nutrients ; 11(3)2019 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-30909386

RESUMEN

Vitamin A is a crucial micronutrient for pregnant women and their fetuses. In addition to being essential for morphological and functional development and for ocular integrity, vitamin A exerts systemic effects on several fetal organs and on the fetal skeleton. Vitamin A requirements during pregnancy are therefore greater. Vitamin A deficiency (VAD) remains the leading cause of preventable blindness in the world. VAD in pregnant women is a public health issue in most developing countries. In contrast, in some developed countries, excessive vitamin A intake during pregnancy can be a concern since, when in excess, this micronutrient may exert teratogenic effects in the first 60 days following conception. Routine prenatal vitamin A supplementation for the prevention of maternal and infant morbidity and mortality is not recommended; however, in regions where VAD is a public health issue, vitamin A supplementation is recommended to prevent night blindness. Given the importance of this topic and the lack of a complete, up-to-date review on vitamin A and pregnancy, an extensive review of the literature was conducted to identify conflicting or incomplete data on the topic as well as any gaps in existing data.


Asunto(s)
Suplementos Dietéticos , Complicaciones del Embarazo/prevención & control , Deficiencia de Vitamina A/prevención & control , Vitamina A/administración & dosificación , Vitaminas/administración & dosificación , Femenino , Humanos , Recién Nacido , Fenómenos Fisiologicos Nutricionales Maternos , Ceguera Nocturna/prevención & control , Embarazo , Atención Prenatal/métodos
2.
Public Health Nutr ; 19(5): 851-60, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26055085

RESUMEN

OBJECTIVE: To describe the prevalence and determinants of gestational night blindness in pregnant women receiving care in a hospital in Rio de Janeiro, Brazil. DESIGN: Cross-sectional study of pregnant and postpartum women receiving care in a public hospital in Rio de Janeiro from 1999 to 2001 (group I; n 225) or from 2005 to 2008 (group II; n 381). Night blindness was identified through a standardized and validated interview (WHO, 1996). The determinants of gestational night blindness were identified through a hierarchical logistic regression model. SETTING: Public maternity hospital in Rio de Janeiro, RJ, Brazil. SUBJECTS: Adult pregnant and postpartum women (n 606), aged ≥20 years. RESULTS: The prevalence of gestational night blindness was 9·9 %. The final model revealed that not living in the South Zone of Rio de Janeiro (distal level: adjusted OR=1·846; 95 % CI 1·002, 3·401), belonging to group I (intermediate level: adjusted OR=2·183; 95 % CI 1·066, 4·471) and for the proximal level, having a history of abortion (adjusted OR=2·840; 95 % CI 1·134, 7·115) and having anaemia during the first and second trimesters of pregnancy (adjusted OR=3·776; 95 % CI 1·579, 9·029) were determinants of gestational night blindness. CONCLUSION: Gestational night blindness should be assessed for during the prenatal care of all pregnant women, especially those living in deprived areas of the city and/or who have a history of abortion or anaemia. Nutritional monitoring is recommended during pregnancy to control gestational night blindness.


Asunto(s)
Ácido Ascórbico/administración & dosificación , Ácido Fólico/administración & dosificación , Alimentos Fortificados , Hierro de la Dieta/administración & dosificación , Ceguera Nocturna/epidemiología , Vitamina A/administración & dosificación , Aborto Inducido , Adulto , Anemia Ferropénica/complicaciones , Anemia Ferropénica/tratamiento farmacológico , Brasil/epidemiología , Estudios Transversales , Suplementos Dietéticos , Femenino , Humanos , Modelos Logísticos , Ceguera Nocturna/etiología , Ceguera Nocturna/prevención & control , Periodo Posparto , Embarazo , Atención Prenatal , Prevalencia , Factores Socioeconómicos , Deficiencia de Vitamina A/complicaciones , Deficiencia de Vitamina A/tratamiento farmacológico , Adulto Joven
3.
Ophthalmologe ; 113(2): 156-9, 2016 Feb.
Artículo en Alemán | MEDLINE | ID: mdl-26205745

RESUMEN

CASE REPORT: This article reports the case of a 50-year-old female patient who presented with reduced visual acuity of 0.8 p and metamorphopsia of the left eye caused by focal vitreomacular traction and who was treated with intravitreal Jetrea® (ocriplasmin). After injection the patient suffered from progressive nyctalopia and visual field defects. Electroretinography (ERG) showed decreased amplitudes and optical coherence tomography (OCT) showed decreased reflectivity in the ellipsoid layer that persisted for 2 months after treatment. CONCLUSION: Before injection of Jetrea® a detailed clarification of such potential side effects is necessary to increase patient compliance in the follow-up.


Asunto(s)
Fibrinolisina/administración & dosificación , Fibrinolisina/efectos adversos , Inyecciones Intravítreas/efectos adversos , Ceguera Nocturna/inducido químicamente , Ceguera Nocturna/diagnóstico , Fragmentos de Péptidos/administración & dosificación , Fragmentos de Péptidos/efectos adversos , Desprendimiento del Vítreo/tratamiento farmacológico , Diagnóstico Diferencial , Femenino , Fibrinolíticos/administración & dosificación , Fibrinolíticos/efectos adversos , Humanos , Persona de Mediana Edad , Ceguera Nocturna/prevención & control , Enfermedades de la Retina , Desprendimiento del Vítreo/complicaciones
4.
Eur J Clin Nutr ; 69(6): 752-4, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25804276

RESUMEN

We report a case of acquired night blindness in a developed country (Spain) without risk factors for nutritional deficiency disease or family history of hereditary retinal disease. A 76-year-old woman presented with acquired night blindness of 6-month progression. After a thorough inquiry about eating patterns she becomes suspicious of vitamin A low dietary intake, which is analytically confirmed and successfully treated. Despite being very uncommon in our environment and even more in patients without digestive problems, in a patient reporting acquired night blindness vitamin A deficiency should not be discarded until eating patterns have been investigated. It might be especially relevant in certain socioeconomic situations and eating disorders such as bulimia or anorexia nervosa.


Asunto(s)
Dieta/efectos adversos , Fenómenos Fisiológicos Nutricionales del Anciano , Conducta Alimentaria , Ceguera Nocturna/etiología , Deficiencia de Vitamina A/etiología , Anciano , Suplementos Dietéticos , Progresión de la Enfermedad , Femenino , Humanos , Ceguera Nocturna/fisiopatología , Ceguera Nocturna/prevención & control , Evaluación Nutricional , España , Resultado del Tratamiento , Vitamina A/uso terapéutico , Deficiencia de Vitamina A/diagnóstico , Deficiencia de Vitamina A/dietoterapia , Deficiencia de Vitamina A/fisiopatología
5.
Nutr Hosp ; 29(5): 1132-40, 2014 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-24951995

RESUMEN

INTRODUCTION: In developing countries, night blindness is a very common public health problem among pregnant women. OBJECTIVE: Evaluate the effect of the changes occurred on prenatal care concerning prenatal nutritional care on the occurrence of night blindness (XN) in adult pregnant women in public maternity hospital in Rio de Janeiro between 1999-2001 and between 2007-2008. METHODS: Two cross-sectional studies were conducted, been the first one conducted between 1999-2001 and the second one between 2007-2008. Were studied 402 puerperal women, 225 between 1999-2001 (GI) and 177 between 2007-2008 (GII). The gestational XN was investigated during the immediate puerperium (GI) and during the prenatal/puerperium (GII), diagnosed by the World Health Organization. The study collected sociodemographic, clinical, obstetric, anthropometric and prenatal care information. RESULTS: It verified significant reduce of prevalence of gestational XN (GI = 18.7% e GII = 0.6%, p < 0.001). The occurrence of gestational XN was associated to sanitary conditions, education level, more than six prenatal consultations, miscarriage at last pregnancy, higher average number of deliveries, average number of prenatal care consultations and prenatal nutritional (p < 0.05). There was no association between gestational XN and marital status, skin color, pre-gestational nutritional status, adequacy of gain of total gestational weight, gestational anaemia and average number of pregnancies (p > 0.05). CONCLUSION: The inclusion of nutritional care in routine prenatal care may have contributed to the reduction of gestational XN. Studies to assess the nutritional intervention in the prevention and treatment of gestational XN at regions at greatest risk are suggested.


Introducción: En los países en desarrollo, la ceguera nocturna (CN) es un problema muy común de la salud pública entre las mujeres embarazadas. Objetivo: Evaluar el efecto de los cambios ocurridos en la atención prenatal sobre el cuidado nutricional prenatal sobre la aparición de CN en mujeres adultas embarazadas en una maternidad pública en Rio de Janeiro entre 1999-2001 y entre 2007-2008. Métodos: Se realizaron dos estudios transversales, el primero entre 1999-2001 y el segundo entre 2007-2008. Se estudiaron 402 mujeres puérperas, 225 entre 1999-2001 (GI) y 177 entre 2007-2008 (GII). La CN gestacional fue investigada durante el puerperio inmediato (GI) y durante el prenatal/puerperio (GII), diagnosticada por la Organización Mundial de La Salud. El estudio incluió informaciones sociodemográficas, clínicas, obstétricas, antropométricas y del cuidado prenatal. Resultados: Se verificó reducción significativa de la prevalencia de CN gestacional (GI = 18,7% e GII = 0,6%, p < 0,001). La ocurrencia de CN gestacional se asoció con las condiciones sanitarias, el nivel de educación, más de seis consultas prenatales, abortos espontáneos en el último embarazo, mayor número promedio de partos, el número promedio de consultas de atención prenatal y de nutrición prenatal (p < 0,05). No hubo asociación entre CN gestacional y el estado civil, color de piel, estado nutricional pregestacional, adecuación de la ganancia de peso durante la gestación, incluyendo anemia gestacional y el número medio de embarazos (p > 0,05). Conclusión: La inclusión de la atención nutricional en el cuidado prenatal de rutina puede haber contribuido para la reducción de CN gestacional. Se sugiere más estudios para evaluar la intervención nutricional en la prevención y el tratamiento de CN gestacional en las regiones de mayor riesgo.


Asunto(s)
Ceguera Nocturna/epidemiología , Ceguera Nocturna/prevención & control , Atención Prenatal/estadística & datos numéricos , Fenómenos Fisiologicos de la Nutrición Prenatal , Adulto , Antropometría , Brasil/epidemiología , Estudios Transversales , Femenino , Humanos , Recién Nacido , Periodo Posparto , Embarazo , Prevalencia , Adulto Joven
6.
Obes Surg ; 23(8): 1244-51, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23462856

RESUMEN

BACKGROUND: This study aims to investigate the nutritional status of vitamin A (VA) using biochemical and functional indicators in subjects with class III obesity, before and after RYGB, supplemented with three protocols. METHODS: The sample comprised 90 patients, with BMI ≥40 kg/m(2), divided into three groups: G1 that received routine supplementation containing 5,000 IU of retinol daily; G2 that received 10,000 IU of retinol daily; and G3 that received routine supplementation plus complementary of 50,000 IU of retinol intramuscularly every month. The status of VA was evaluated before (T0), 30 days (T1), and 180 days (T2) after surgery. RESULTS: The vitamin A deficiency (VAD) in G1, G2, and G3 was respectively 20.7, 21.2, and 20.2 % as regards retinol and 37.8, 63.3, and 40 % as regards ß-carotene in T0; 26.7, 10, and 23.4 % as regards retinol and 68, 37, and 32 % as regards ß-carotene in T1; and 21, 8.7, and 20.2 % as regards retinol and 63.3, 20, and 32 % as regards ß-carotene in T2. A reduction of retinol and ß-carotene with increasing BMI and waist circumference was observed in T0. The prevalence of night blindness (XN) in groups 1, 2, and 3 was respectively 23.3, 26.7, and 16.7 % in T0; 56.7, 40, and 60 % in T1; and 70, 43, and 63.3 % in T2. CONCLUSION: The study showed high prevalence of VAD. Among the supplementation protocols used, the one containing 10,000 IU of retinol showed the best impact. However, in cases of more severe VAD, intramuscular supplementation should be considered. The prevalence of XN, justifies attention to this segment of population.


Asunto(s)
Suplementos Dietéticos , Derivación Gástrica/efectos adversos , Ceguera Nocturna/prevención & control , Obesidad Mórbida/cirugía , Deficiencia de Vitamina A/tratamiento farmacológico , Vitamina A/uso terapéutico , Vitaminas/uso terapéutico , beta Caroteno/uso terapéutico , Adulto , Índice de Masa Corporal , Brasil/epidemiología , Femenino , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Ceguera Nocturna/sangre , Ceguera Nocturna/tratamiento farmacológico , Ceguera Nocturna/etiología , Estado Nutricional , Periodo Posoperatorio , Prevalencia , Estudios Prospectivos , Resultado del Tratamiento , Deficiencia de Vitamina A/sangre , Deficiencia de Vitamina A/etiología , Circunferencia de la Cintura
7.
BMJ ; 343: d5094, 2011 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-21868478

RESUMEN

OBJECTIVE: To determine if vitamin A supplementation is associated with reductions in mortality and morbidity in children aged 6 months to 5 years. DESIGN: Systematic review and meta-analysis. Two reviewers independently assessed studies for inclusion. Data were double extracted; discrepancies were resolved by discussion. Meta-analyses were performed for mortality, illness, vision, and side effects. DATA SOURCES: Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, Medline, Embase, Global Health, Latin American and Caribbean Health Sciences, metaRegister of Controlled Trials, and African Index Medicus. Databases were searched to April 2010 without restriction by language or publication status. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Randomised trials of synthetic oral vitamin A supplements in children aged 6 months to 5 years. Studies of children with current illness (such as diarrhoea, measles, and HIV), studies of children in hospital, and studies of food fortification or ß carotene were excluded. RESULTS: 43 trials with about 215,633 children were included. Seventeen trials including 194,483 participants reported a 24% reduction in all cause mortality (rate ratio=0.76, 95% confidence interval 0.69 to 0.83). Seven trials reported a 28% reduction in mortality associated with diarrhoea (0.72, 0.57 to 0.91). Vitamin A supplementation was associated with a reduced incidence of diarrhoea (0.85, 0.82 to 0.87) and measles (0.50, 0.37 to 0.67) and a reduced prevalence of vision problems, including night blindness (0.32, 0.21 to 0.50) and xerophthalmia (0.31, 0.22 to 0.45). Three trials reported an increased risk of vomiting within the first 48 hours of supplementation (2.75, 1.81 to 4.19). CONCLUSIONS: Vitamin A supplementation is associated with large reductions in mortality, morbidity, and vision problems in a range of settings, and these results cannot be explained by bias. Further placebo controlled trials of vitamin A supplementation in children between 6 and 59 months of age are not required. However, there is a need for further studies comparing different doses and delivery mechanisms (for example, fortification). Until other sources are available, vitamin A supplements should be given to all children at risk of deficiency, particularly in low and middle income countries.


Asunto(s)
Ceguera Nocturna/prevención & control , Deficiencia de Vitamina A/prevención & control , Vitamina A/uso terapéutico , Sesgo , Mortalidad del Niño , Preescolar , Países en Desarrollo , Diarrea/epidemiología , Diarrea/prevención & control , Femenino , Humanos , Lactante , Mortalidad Infantil , MEDLINE , Masculino , Sarampión/epidemiología , Sarampión/prevención & control , Morbilidad , Mortalidad , Ceguera Nocturna/epidemiología , Prevención Primaria/métodos , Ensayos Clínicos Controlados Aleatorios como Asunto , Infecciones del Sistema Respiratorio/epidemiología , Infecciones del Sistema Respiratorio/prevención & control , Deficiencia de Vitamina A/tratamiento farmacológico , Deficiencia de Vitamina A/epidemiología , Vómitos/epidemiología , Vómitos/prevención & control , Xeroftalmia/epidemiología , Xeroftalmia/prevención & control
9.
JAMA ; 305(19): 1986-95, 2011 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-21586714

RESUMEN

CONTEXT: Maternal vitamin A deficiency is a public health concern in the developing world. Its prevention may improve maternal and infant survival. OBJECTIVE: To assess efficacy of maternal vitamin A or beta carotene supplementation in reducing pregnancy-related and infant mortality. DESIGN, SETTING, AND PARTICIPANTS: Cluster randomized, double-masked, placebo-controlled trial among pregnant women 13 to 45 years of age and their live-born infants to 12 weeks (84 days) postpartum in rural northern Bangladesh between 2001 and 2007. Interventions Five hundred ninety-six community clusters (study sectors) were randomized for pregnant women to receive weekly, from the first trimester through 12 weeks postpartum, 7000 µg of retinol equivalents as retinyl palmitate, 42 mg of all-trans beta carotene, or placebo. Married women (n = 125,257) underwent 5-week surveillance for pregnancy, ascertained by a history of amenorrhea and confirmed by urine test. Blood samples were obtained from participants in 32 sectors (5%) for biochemical studies. MAIN OUTCOME MEASURES: All-cause mortality of women related to pregnancy, stillbirth, and infant mortality to 12 weeks (84 days) following pregnancy outcome. RESULTS: Groups were comparable across risk factors. For the mortality outcomes, neither of the supplement group outcomes was significantly different from the placebo group outcomes. The numbers of deaths and all-cause, pregnancy-related mortality rates (per 100,000 pregnancies) were 41 and 206 (95% confidence interval [CI], 140-273) in the placebo group, 47 and 237 (95% CI, 166-309) in the vitamin A group, and 50 and 250 (95% CI, 177-323) in the beta carotene group. Relative risks for mortality in the vitamin A and beta carotene groups were 1.15 (95% CI, 0.75-1.76) and 1.21 (95% CI, 0.81-1.81), respectively. In the placebo, vitamin A, and beta carotene groups the rates of stillbirth and infant mortality were 47.9 (95% CI, 44.3-51.5), 45.6 (95% CI, 42.1-49.2), and 51.8 (95% CI, 48.0-55.6) per 1000 births and 68.1 (95% CI, 63.7-72.5), 65.0 (95% CI, 60.7-69.4), and 69.8 (95% CI, 65.4-72.3) per 1000 live births, respectively. Vitamin A compared with either placebo or beta carotene supplementation increased plasma retinol concentrations by end of study (1.46 [95% CI, 1.42-1.50] µmol/L vs 1.13 [95% CI, 1.09-1.17] µmol/L and 1.18 [95% CI, 1.14-1.22] µmol/L, respectively; P < .001) and reduced, but did not eliminate, gestational night blindness (7.1% for vitamin A vs 9.2% for placebo and 8.9% for beta carotene [P < .001 for both]). CONCLUSION: Use of weekly vitamin A or beta carotene in pregnant women in Bangladesh, compared with placebo, did not reduce all-cause maternal, fetal, or infant mortality. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00198822.


Asunto(s)
Mortalidad Infantil , Mortalidad Materna , Complicaciones del Embarazo/prevención & control , Vitamina A/análogos & derivados , Vitaminas/uso terapéutico , beta Caroteno/uso terapéutico , Adolescente , Adulto , Países en Desarrollo , Suplementos Dietéticos , Diterpenos , Femenino , Humanos , Lactante , Recién Nacido , Persona de Mediana Edad , Ceguera Nocturna/tratamiento farmacológico , Ceguera Nocturna/etiología , Ceguera Nocturna/prevención & control , Embarazo , Resultado del Embarazo , Atención Prenatal , Ésteres de Retinilo , Población Rural , Mortinato , Vitamina A/uso terapéutico , Deficiencia de Vitamina A/complicaciones , Deficiencia de Vitamina A/tratamiento farmacológico , Deficiencia de Vitamina A/prevención & control , Adulto Joven
10.
Food Nutr Bull ; 31(2): 234-41, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20707229

RESUMEN

BACKGROUND: Several surveys conducted over a period of 40 years have shown that vitamin A deficiency is a serious public health problem in Ethiopia. To address the problem effectively, up-to-date, comprehensive information on the magnitude and distribution of vitamin A deficiency is needed. OBJECTIVE: A national vitamin A survey was conducted to assess the national and regional prevalence rates of vitamin A deficiency in Ethiopia. METHODS: The survey employed a multistage, cluster-sampling approach and a cross-sectional study design. A total of 23,148 children aged 6 to 71 months and their respective mothers were examined for clinical signs and symptoms, and blood samples were collected from 1200 systematically selected children for serum retinol analysis. RESULTS: The findings indicated national prevalence rates of 1.7% for Bitot's spots among children. 0.8% for night-blindness among children, and 1.8% for night-blindness among mothers. Nationally, 37.7% of children (95% CI, 35.6% to 39.9%) had deficient serum retinol levels, 50.7% had been sick in the previous 15 days, and 22.6% had received vitamin A supplements in the previous 6 months. The prevalence of clinical vitamin A deficiency was significantly (p < .05) higher among children who were male, older, or rural residents. CONCLUSIONS: The study confirmed that vitamin A deficiency is a serious public health problem in Ethiopia. Intensification of the ongoing vitamin A supplementation program, postpartum vitamin A supplementation for mothers, intensifying efforts to improve the health status of preschool age children, and promotion of production and consumption of fruits and vegetables are recommended.


Asunto(s)
Deficiencia de Vitamina A/epidemiología , Deficiencia de Vitamina A/fisiopatología , Adulto , Envejecimiento , Preescolar , Estudios Transversales , Suplementos Dietéticos , Etiopía/epidemiología , Femenino , Humanos , Lactante , Masculino , Madres , Ceguera Nocturna/sangre , Ceguera Nocturna/epidemiología , Ceguera Nocturna/prevención & control , Política Nutricional , Encuestas Nutricionales , Prevalencia , Población Rural , Índice de Severidad de la Enfermedad , Factores Sexuales , Vitamina A/sangre , Deficiencia de Vitamina A/sangre , Deficiencia de Vitamina A/prevención & control
11.
Ophthalmic Epidemiol ; 16(3): 193-7, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19437315

RESUMEN

PURPOSE: This study aimed to identify risk factors associated with maternal night blindness in rural South India. METHODS: At delivery, women enrolled in a population-based trial of newborn vitamin A supplementation were asked whether they were night blind at any time during the pregnancy. Multivariate logistic regression was used to identify socioeconomic, demographic, and pregnancy-related factors associated with maternal night blindness. RESULTS: Women reported night blindness in 687 (5.2%) of 13,171 pregnancies. In a multivariate model, having a concrete roof (Odds Ratio (OR): 0.60, 95% Confidence Interval (CI): 0.47, 0.78), religion other than Hindu (OR: 0.46, 95% CI: 0.27, 0.76), maternal literacy (OR: 0.58, 95% CI: 0.49, 0.69), and maternal age from 25 to 29 years (OR: 0.68, 95% CI: 0.50, 0.93) were associated with a lower risk of night blindness in pregnancy. The odds of night blindness were higher for those leasing rather than owning land (OR: 1.78, 95%CI: 1.08, 2.93), parity 6 or more compared to 0 (OR: 2.11, 95% CI: 1.09, 4.08), and with twin pregnancies (OR: 3.23, 95% CI: 1.93, 5.41). Factors not associated with night blindness in the multivariate model were other markers of socioeconomic status such as electricity in the house, radio and television ownership, type of cooking fuel and household transportation, and number of children under 5 years of age in the household. CONCLUSIONS: Maternal night blindness was prevalent in this population. Being pregnant with twins and of higher parity put women at higher risk. Maternal literacy and higher socioeconomic status lowered the risk.


Asunto(s)
Ceguera Nocturna/epidemiología , Complicaciones del Embarazo/epidemiología , Población Rural/estadística & datos numéricos , Adulto , Composición Familiar , Femenino , Indicadores de Salud , Humanos , India/epidemiología , Bienestar Materno , Ceguera Nocturna/prevención & control , Oportunidad Relativa , Paridad , Embarazo , Complicaciones del Embarazo/prevención & control , Factores de Riesgo , Clase Social , Deficiencia de Vitamina A/epidemiología , Salud de la Mujer , Xeroftalmia/epidemiología
12.
Hum Factors ; 49(3): 518-31, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17552314

RESUMEN

OBJECTIVE: An evaluation study was conducted to answer the question of which system properties of night vision enhancement systems (NVESs) provide a benefit for drivers without increasing their workload. BACKGROUND: Different infrared sensor, image processing, and display technologies can be integrated into an NVES to support nighttime driving. Because each of these components has its specific strengths and weaknesses, careful testing is required to determine their best combination. METHOD: Six prototypical systems were assessed in two steps. First, a heuristic evaluation with experts from ergonomics, perception, and traffic psychology was conducted. It produced a broad overview of possible effects of system properties on driving. Based on these results, an experimental field study with 15 experienced drivers was performed. Criteria used to evaluate the development potential of the six prototypes were the usability dimensions of effectiveness, efficiency, and user satisfaction (International Organization for Standardization, 1998). RESULTS: Results showed that the intelligibility of information, the easiness with which obstacles could be located in the environment, and the position of the display presenting the output of the system were of crucial importance for the usability of the NVES and its acceptance. CONCLUSION: All relevant requirements are met best by NVESs that are positioned at an unobtrusive location and are equipped with functions for the automatic identification of objects and for event-based warnings. APPLICATION: These design recommendations and the presented approach to evaluate the systems can be directly incorporated into the development process of future NVESs.


Asunto(s)
Conducción de Automóvil , Oscuridad , Ceguera Nocturna/prevención & control , Agudeza Visual , Adulto , Anciano , Presentación de Datos , Femenino , Humanos , Rayos Infrarrojos , Masculino , Persona de Mediana Edad
13.
Klin Monbl Augenheilkd ; 223(5): 428-30, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16705523

RESUMEN

BACKGROUND: Visual loss, photophobia and night-blindness in a middle-aged patient with a previous history of cancer are highly suggestive of cancer-associated retinopathy. HISTORY AND SIGNS: A 63-year-old man complained of slowly progressive bilateral visual loss, photophobia and night-blindness. His past medical history was remarkable for surgical and medical treatment of a carcinoma of the base of his tongue nine years earlier. Visual acuity was 0.3 RE and 0.15 LE, with constricted visual field in both eyes. Ocular examination and fluorescein angiography were non-relevant. Electroretinography revealed diffuse cone and rod dysfunction. ICG angiography showed multiple small widespread hyperfluorescent spots. A chest CT scan revealed multiple focal lesions which were biopsied. Histological diagnosis was sarcoidosis. THERAPY AND OUTCOME: Upon systemic steroid therapy, visual function gradually improved, and ICG anomalies disappeared. Vision recovered to 1.0 RE and 0.8 LE with normal visual field in both eyes. CONCLUSION: Sarcoidosis may present as an autoimmune retinal dysfunction with photophobia and night blindness as the presenting symptoms.


Asunto(s)
Enfermedades de la Coroides/diagnóstico , Enfermedades de la Coroides/terapia , Enfermedades de la Retina/diagnóstico , Enfermedades de la Retina/terapia , Sarcoidosis/diagnóstico , Sarcoidosis/terapia , Enfermedades Autoinmunes/diagnóstico , Enfermedades Autoinmunes/terapia , Humanos , Masculino , Persona de Mediana Edad , Ceguera Nocturna/etiología , Ceguera Nocturna/prevención & control , Fotofobia/etiología , Fotofobia/prevención & control , Enfermedades de la Retina/inmunología
14.
Klin Monbl Augenheilkd ; 223(5): 443-6, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16705527

RESUMEN

BACKGROUND: Rapidly progressing bilateral night blindness in an elderly patient suggests primarily a diagnosis of paraneoplastic retinopathy. Occasionally diffuse rod dysfunction can result from vitamin A deficiency. HISTORY AND SIGNS: A 70-year-old man complained of progressive night blindness and xanthopsia for the past 6 months. Visual acuity was 0.8 in both eyes with severe dyschromatopsia. Slit-lamp and fundus examination were normal. Visual field disclosed bilateral depression. Scotopic full-field ERG was severely reduced. The patient's medical history revealed an acute pancreatitis one year ago, followed by chronic jaundice and an increased blood bilirubin. Serum vitamin A level was decreased to 0.1 micromol/L (normal range 1.5 to 4.0). THERAPY AND OUTCOME: Intramuscular injections of vitamin A were provided. Subjective visual improvement was reported already one day after initiation of therapy. Scotopic full-field ERG was markedly improved 3 days after the injection and was only slightly subnormal 3 months later. CONCLUSIONS: In developed countries, vitamin A deficiency usually results from malabsorption syndromes and manifests initially by rod more than cone dysfunction. This diagnosis should be entertained early as vitamin A supplementation induces a rapid restoration of vision.


Asunto(s)
Defectos de la Visión Cromática/prevención & control , Síndromes de Malabsorción/tratamiento farmacológico , Ceguera Nocturna/prevención & control , Trastornos de la Pigmentación/prevención & control , Deficiencia de Vitamina A/tratamiento farmacológico , Vitamina A/administración & dosificación , Xeroftalmia/prevención & control , Anciano , Humanos , Síndromes de Malabsorción/diagnóstico , Masculino , Pigmentación de la Piel
15.
Klin Monbl Augenheilkd ; 223(5): 453-5, 2006 May.
Artículo en Alemán | MEDLINE | ID: mdl-16705530

RESUMEN

BACKGROUND: Vitamin and trace element deficiencies may cause visual disturbances. Before starting a substitutional therapy, specific investigations should be performed. HISTORY AND SIGNS: We present a kidney-transplanted patient who suffered for 6 months from night blindness. The electroretinography showed a severe decrease of the rod activity. Except for an irregular pigmentation in the far periphery, the fundus appeared normal. These findings were indicative of a vitamin A and zinc deficiency. The laboratory tests showed decreased vitamin A and zinc serum levels. THERAPY AND OUTCOME: After three months of substitutional therapy the electroretinogram had normalized and the patient was free of symptoms. CONCLUSIONS: Visual disturbances due to vitamin and trace element deficiencies are rare in Europe. If suspected, since the diagnosis and the treatment of nutritional deficiencies are simple, specific investigations and a substitutional therapy should be initiated.


Asunto(s)
Anorexia Nerviosa/complicaciones , Trasplante de Riñón/efectos adversos , Ceguera Nocturna/etiología , Ceguera Nocturna/prevención & control , Deficiencia de Vitamina A/complicaciones , Deficiencia de Vitamina A/terapia , Zinc/administración & dosificación , Zinc/deficiencia , Adulto , Suplementos Dietéticos , Femenino , Humanos , Ceguera Nocturna/diagnóstico , Vitamina A/administración & dosificación
16.
Ann Clin Biochem ; 40(Pt 3): 292-4, 2003 May.
Artículo en Inglés | MEDLINE | ID: mdl-12803847

RESUMEN

We describe a patient with a 6-year history of pancreatic malabsorption following surgical subtotal pancreatectomy. She presented at 33 weeks of pregnancy with night blindness as a result of vitamin A deficiency. She had had two successful pregnancies 9 and 8 years previously, giving birth to a healthy baby boy on each occasion. We suggest that patients with long-term malabsorption due to intestinal or pancreatic disease should have vitamin A status checked prior to and during pregnancy so that prompt supplementation can be commenced if necessary. The possibility that vitamin A deficiency may be contributing to anaemia present in pregnancy should also be considered.


Asunto(s)
Ceguera Nocturna/etiología , Pancreatectomía , Complicaciones Posoperatorias , Complicaciones del Embarazo/prevención & control , Deficiencia de Vitamina A/etiología , Femenino , Humanos , Lactante , Síndromes de Malabsorción/complicaciones , Masculino , Ceguera Nocturna/prevención & control , Embarazo , Vitamina A/administración & dosificación , Deficiencia de Vitamina A/prevención & control
18.
Hum Factors ; 43(4): 620-30, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-12002010

RESUMEN

Visual recognition functions, such as acuity and contrast sensitivity, deteriorate rapidly over the declining luminances found during civil twilight. Thus civil twilight, a critical part of the transition between daylight and darkness, represents lighting conditions that may be useful to describe artificial illumination. Automotive headlamps project a three-dimensional beam that ranges from illumination levels comparable to daylight at the vehicle to the dark limit of civil twilight (3.3 1x) at some distance ahead. This twilight envelope is characterized as a distance beyond which foveal visual functions are severely impaired, and thus it provides a general, functional description of the useful extent of the headlamp beam. This user-centered approach to describing illumination is useful for characterizing visibility when driving at night or in other artificially lit environments. This paper discusses the twilight envelope approach and its application to intervehicle variations in headlamp systems. Actual or potential applications of this research include user-centered description of artificial illumination and driver/pedestrian safety education.


Asunto(s)
Accidentes de Tránsito/prevención & control , Conducción de Automóvil , Iluminación , Humanos , Ceguera Nocturna/prevención & control , Seguridad , Pruebas de Visión , Agudeza Visual
19.
Am J Clin Nutr ; 72(4): 1004-9, 2000 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11010944

RESUMEN

BACKGROUND: Impaired dark adaptation occurs commonly in vitamin A deficiency. OBJECTIVE: We sought to examine the responsiveness of dark-adaptation threshold to vitamin A and beta-carotene supplementation in Nepali women. DESIGN: The dark-adapted pupillary response was tested in 298 pregnant women aged 15-45 y in a placebo-controlled trial of vitamin A and beta-carotene; 131 of these women were also tested at 3 mo postpartum. Results were compared with those for 100 nonpregnant US women of similar age. The amount of light required for pupillary constriction was recorded after bleaching and dark adaptation. RESULTS: Pregnant women receiving vitamin A had better dark-adaptation thresholds (-1.24 log cd/m(2)) than did those receiving placebo (-1.11 log cd/m(2); P: = 0. 03) or beta-carotene (-1.13 log cd/m(2); P: = 0.05) (t tests with Bonferroni correction). Dark-adaptation threshold was associated with serum retinol concentration in pregnant women receiving placebo (P: = 0.001) and in those receiving beta-carotene (P: = 0.003) but not in those receiving vitamin A. Among women receiving placebo, mean dark-adaptation thresholds were better during the first trimester (-1.23 log cd/m(2)) than during the second and third trimesters (-1.03 log cd/m(2); P: = 0.02, t test). The mean threshold of nonpregnant US women (-1.35 log cd/m(2)) was better than that of all 3 Nepali groups (P: < 0.001, t test, for all 3 groups). CONCLUSIONS: During pregnancy, pupillary dark adaptation was strongly associated with serum retinol concentration and improved significantly in response to vitamin A supplementation. This noninvasive testing technique is a valid indicator of population vitamin A status in women of reproductive age.


Asunto(s)
Adaptación a la Oscuridad/efectos de los fármacos , Ceguera Nocturna/prevención & control , Deficiencia de Vitamina A/tratamiento farmacológico , Vitamina A/administración & dosificación , beta Caroteno/administración & dosificación , Adolescente , Adulto , Antropometría , Cromatografía Líquida de Alta Presión , Suplementos Dietéticos , Femenino , Edad Gestacional , Humanos , Entrevistas como Asunto , Lactancia/fisiología , Modelos Lineales , Persona de Mediana Edad , Nepal , Estado Nutricional , Embarazo , Complicaciones del Embarazo/tratamiento farmacológico , Complicaciones del Embarazo/fisiopatología , Análisis de Regresión , Población Rural , Vitamina A/sangre , Deficiencia de Vitamina A/fisiopatología
20.
J Indian Med Assoc ; 98(9): 525-9, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11291784

RESUMEN

Adequate maternal vitamin A nutrition is essential for successful pregnancy outcome and estimation of serum retinol among pregnant women enables a precise and objective assessment of vitamin A status, during pregnancy, even in subclinical state. In order to evaluate vitamin A status during pregnancy, and its relationship with personal and pregnancy related variables of the mother, 300 antenatal clinic attenders were interviewed at RG Kar Medical College and Hospital, Calcutta and tested for serum retinol, using Carr-Price test. Serum retinol values less than 30 microg/dl and 20 microg/dl, in this study, were considered as poor and severe vitamin A deficiency respectively. According to this 14.7% and 4% pregnant women were found to be suffering from poor and severe vitamin A deficiency respectively. Clinical signs of vitamin A deficiency (eg, nightblindness) were reported only among 60% cases of the deficient population. The problems of vitamin A deficiency were associated with low literacy and poor nutritional status of the mother, advanced gestational age of current pregnancy,increased number of pregnancies, shorter interval between births and poor dietary intake of vitamin A rich foods during pregnancy. The study thus raises the question of supplementation of vitamin A, during pregnancy, in Indian context where habitual diets are either inadequate or deficient in vitamin A.


Asunto(s)
Conducta Alimentaria , Ceguera Nocturna/epidemiología , Política Nutricional , Complicaciones del Embarazo/epidemiología , Deficiencia de Vitamina A/epidemiología , Vitamina A/sangre , Adolescente , Adulto , Suplementos Dietéticos , Conducta Alimentaria/etnología , Femenino , Humanos , Incidencia , India/epidemiología , Ceguera Nocturna/prevención & control , Embarazo , Complicaciones del Embarazo/prevención & control , Prevalencia , Factores de Riesgo , Muestreo , Factores Socioeconómicos , Deficiencia de Vitamina A/sangre , Deficiencia de Vitamina A/prevención & control
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