Gastric outlet obstruction due to an intragastric balloon in a patient returning from the Caribbean.

Key Clinical Message: Gastric outlet obstruction can be a dangerous complication of intragastric balloons, as it can result in severe metabolic alkalosis. As weight loss procedures and medical tourism become more popular, physicians should have a high index of suspicion for complications of invasive procedures, particularly in returning travelers. Abstract: Intragastric balloons for weight loss have decreased in frequency in the United States. However, they are still frequent in low- and middle-income countries. Severe complications occur in less than 3% of patients who undergo this procedure. Herein, we present a case of gastric outlet obstruction, severe metabolic alkalosis, and refeeding syndrome in a patient returning from the Dominican Republic. She presented with 2 weeks of emesis and obstipation, followed by a pre-syncope and altered mental status. An intragastric mass was observed on computerized tomography, which was characterized as an intragastric balloon and retrieved endoscopically. All metabolic derangements were corrected, and the patient improved without sequelae. As weight loss procedures and medical tourism become more popular, physicians should have a high index of suspicion for complications of invasive procedures, particularly in returning travelers.

Conocimiento Especializado del Profesor de Matemáticas en la Enseñanza de la Modelación de la Elipse a Través de Recursos Tecnológicos / Specialized Knowledge of the Mathematics Teacher in teaching the modeling of the ellipse through technological resources / Conhecimento especializado do professor de matemática no ensino da modelagem da elipse por meio de recursos tecnológicos

Resumen Introducción: en la enseñanza de las matemáticas el uso de recursos tecnológicos ha tomado importancia en las prácticas docentes. No obstante, en algunas ocasiones la no profesionalización de profesores en las aulas les impide poder utilizar este tipo de herramientas de manera eficaz y acordes a las necesidades educativas de hoy día. Objetivo: caracterizar el conocimiento especializado del profesor de matemáticas que enseña de manera efectiva la modelación de la elipse a través de las mediaciones tecnológicas. Materiales y Métodos: el enfoque de esta investigación es de tipo cualitativo, con diseño y estudio de caso instrumental. La recolección de la información se llevó a cabo mediante 13 unidades de observación no participantes, diario de campo, cuestionario y una entrevista semiestructurada a un profesor con formación y experiencia en la enseñanza de la elipse haciendo uso de las TIC. Resultados: Se encontró relaciones entre el conocimiento especializado del profesor de los temas y de la enseñanza de las matemáticas, que contribuyen a la aproximación de la enseñanza de la modelación de la elipse mediante el software GeoGebra. Se Concluye que es indispensable que el profesor tenga conocimiento tanto disciplinar, didáctico-pedagógico y del recurso tecnológico que utiliza para la enseñanza de un contenido específico de las matemáticas.

Abstract Introduction: in the teaching of mathematics, the use of technological resources has become important in teaching practices. However, on some occasions the non-professionalization of teachers in the classroom prevents them from being able to use this type of tools effectively and in accordance with today's educational needs. Objective: characterize the specialized knowledge of the mathematics teacher who effectively teaches the modeling of the ellipse through technological mediations. Materials and Methods: the focus of this research is qualitative, with an instrument al case study design. The information was collected through 13 non-participant observation units, a field diary, a questionnaire and a semi-structured interview with a teacher with training and experience in teaching the ellipse using ICT. Results: Relationships were found between the teacher's specialized knowledge of the topics and the teaching of mathematics, which contribute to the teaching approach to ellipse modeling using the GeoGebra software. It was Concluded that it is essential that the teacher has both disciplinary, didactic-pedagogical knowledge and knowledge of the technological resource that he uses to teach a specific content of mathematics.

Resumo Introdução: no ensino de matemática, o uso de recursos tecnológicos tornou-se importante nas práticas pedagógicas. No entanto, em algumas ocasiões, a não profissionalização dos professores em sala de aula os impede de usar esse tipo de ferramentas de forma eficaz e de acordo com as necessidades educacionais atuais. Objetivo: caracterizar o conhecimento especializado do professor de matemática que efetivamente ensina a modelagem da elipse por meio de mediações tecnológicas. Materiais e Métodos: o foco desta pesquisa é qualitativo, com desenho de estudo de caso instrumental. As informações foram coletadas por meio de 13 unidades de observação não participante, diário de campo, questionário e entrevista semiestruturada com uma professora com formação e experiência no ensino da elipse com TIC. Resultados: foram encontradas relações entre o conhecimento especializado do professor sobre os temas e o ensino de matemática, que contribuem para a abordagem de ensino da modelagem de elipses utilizando o software GeoGebra. Conclusão: é fundamental que o professor tenha tanto conhecimento disciplinar, didático-pedagógico e conhecimento do recurso tecnológico que utiliza para ensinar um conteúdo específico de matemática.

Will evinacumab become the standard treatment for homozygous familial hypercholesterolemia?

Introduction: Homozygous Familial Hypercholesterolemia (HoFH) is a very severe genetic form of hypercholesterolemia. Lacking LDL receptors in the liver, subjects with HoFH have raised plasma levels of LDL cholesterol, and up to 100 times higher risk of premature atherosclerotic cardiovascular disease than the general population.Areas covered: This evaluation is of a phase 3 trial of evinacumab; Evinacumab Lipid Studies in Patients with Homozygous Familial Hypercholesterolemia (ELIPSE HoFH). Evinacumab is a human monoclonal antibody inhibitor of angiopoietin-like protein 3 (ANGPTL3). In ELIPSE HoFH, evinacumab reduced LDL cholesterol by 47.1 ± 4.6%, HDL cholesterol by 30.4%, and triglycerides by 50.4 ± 7.7%.Expert opinion: Evinacumab is not the ideal treatment for HoFH as it does not reduce LDL cholesterol levels to treatment targets while increasing HDL cholesterol. Although the incidence of adverse effects with evinacumab was low in ELIPSE HoFH, further studies are necessary to clarify its effects on liver enzymes and clinical cardiovascular outcomes. Evinacumab is a candidate to become the standard treatment for HoFH, as it may be better tolerated and/or more efficacious than the presently available specific treatment (lomitapide). However, the widespread use of evinacumab to treat high triglycerides or LDL cholesterol is unlikely due to evinacumab decreasing HDL cholesterol.

A Randomized, Controlled Trial Comparing the Impact of a Low-Calorie Ketogenic vs a Standard Low-Calorie Diet on Fat-Free Mass in Patients Receiving an Elipse™ Intragastric Balloon Treatment.

BACKGROUND: The Elipse™ intragastric balloon (EIGB) is a new swallowable balloon for weight loss (WL). Preserving metabolically active fat-free mass (FFM) and resting metabolic rate (RMR) during WL are crucial to maximize fat mass (FM) loss. After EIGB placement, a standard low-calorie diet (LCD) is generally prescribed. A low-calorie ketogenic diet (LCKD) has proven to be safe and effective in reducing FM while preserving FFM and RMR. OBJECTIVE: To prospectively compare the effects on WL, FM, FFM, and RMR in two groups of patients who were randomized to two different diets: LCKD and a standard LCD after EIGB placement. METHODS: WL, FM, FFM, and RMR were measured before EIGB and at 4 months in 48 patients who received either a LCKD (n = 24) or a standard LCD (n = 24). Compliance in following the prescribed diet was determined with food frequency questionnaires in all patients. The impact of LCKD and LCD on renal function was also evaluated. RESULTS: The LCKD group showed a significantly lower decrease in FFM and RMR when compared with the LCD group (3.55 vs 14.3%, p < 0.001; 9.79 vs 11.4%, p < 0.001, respectively). FM decreased more significantly with LCKD compared to LCD (41.6 vs 33.1%, p = 0.0606). Compliance in following the prescribed diets, without negative impact on renal function, was found. CONCLUSION: Based on our findings, despite the small sample size, we were able to support the hypothesis that LCKD is associated with an increased FM loss while reducing the FFM loss and the RMR, without interfering with renal function after EIGB.

Outcomes of a Swallowable Intragastric Balloon (Elipse™) on 96 Overweight and Obese Patients.

BACKGROUND: The traditional gastric balloons have been used for several years to reduce weight in overweight and obese patients, but the need for sedation and upper endoscopy leading to several limitations. The current series is the first study that evaluates the safety and effectiveness of the swallowable gastric (Elipse™) balloon in our population on the national level. METHODS: Ninety-six patients (mean BMI was 33.6 ± 4.3 kg/m2) participated in this study. All patients swallowed one Elipse™ balloon intended to remain in the stomach for 4 months, self-empty, and then pass. Each balloon was filled with 550 mL of filling fluid. Anti-emetics and anti-spasmodic drugs were prescribed for 2-3 days after insertion; proton pump inhibitor was prescribed twice daily 1 week before the procedure and continued until the end of residence time (16-20 weeks). RESULTS: In the current series, at end of the procedure (after 4 months), the overall mean weight loss (WL) was 11.2 ± 5.1 kg, mean waist circumference reduction was 10.9 ± 2.1 cm, and a mean BMI reduction was 4.9 ± 2.0 kg/m2. The percentage of total body weight loss (TBWL%) was 12.1 ± 5.2%. The Elipse™ therapy reported improvements in the metabolic parameters investigated. CONCLUSION: This swallowable gastric balloon (Elipse™) can be safely and successfully swallowed, filled, imaged, and passed with accepted weight loss and clinical improvement in factors related to the metabolic syndrome.

Ultrasound-guided insertion of the Elipse® gastric balloon: technical details, learning curve, and perioperative outcome in 36 cases.

AIM: Our aim is to demonstrate the feasibility of real-time ultrasound-assisted insertion of the Elipse® intragastric balloon for the treatment of overweight and obese patients. METHODS: A plastic gastric phantom filled with water was created to mimic the gastric lumen and to test the operator's ability to recognize the capsule containing the balloon inside. In the clinical phase, we tested the operator's ability to recognize the swallowed capsule and its progressive filling in the gastric lumen by means of ultrasound in 36 consecutive patients with a mean body mass index of 35 in an outpatient setting. RESULTS: The ultrasound hyperechoic signal of the capsule in the gastric lumen was visible early on and was confirmed after the injection of a few milliliters of saline solution in the capsule with a cyst-like shape. The insertion of the balloon was successful in all cases at the first attempt, and the complete filling was monitored in real-time without the need for fluoroscopy. Postprocedure symptoms were limited to the first 24-48 h and were controlled by symptomatic therapy; endoscopic removal of the balloon because of painful distal gastric migration was necessary in one case after 3 months. CONCLUSION: After a learning curve, we were able to demonstrate the placement of the balloon capsule inside the fundus of the stomach under ultrasound guidance without fluoroscopy in all patients in an outpatient setting.

The Efficacy and Safety of a Procedureless Gastric Balloon for Weight Loss: a Systematic Review and Meta-Analysis.

BACKGROUND: Intragastric balloons have been used to bridge the obesity treatment gap with the benefits of being minimally invasive but still required endoscopy. The Elipse intragastric balloon (EIGB) is a swallowable balloon that is spontaneously excreted through a natural orifice at approximately 16 weeks. Several concerns exist, including the treatment efficacy and risk of bowel obstruction. Our meta-analysis aimed to evaluate the efficacy and safety of EIGB. METHODS: A literature search was performed from several databases from database inception to November 2019. Eligible studies must report percent total weight loss (%TWL) after completion of treatment and adverse events. The pooled means and proportions of our data were analyzed using random effects model, generic inverse variance method. RESULTS: Six studies involving 2013 unique patients met our eligibility criteria and were included. The mean baseline BMI ranged from 30.6 to 36.2. The pooled early removal rate was 2.3% (95% CI, 1.1-3.5%; I2 31%). The pooled %TWL after completion of treatment (4-6 months) was 12.8% (95% CI, 11.6-13.9%; I2 83%) and at 12 months was 10.9% (95% CI, 5.0-16.9%, I2 98%). For serious adverse events, three patients had small bowel obstruction, and one patient had gastric perforation requiring surgery. Early expulsion by emesis and early deflation were seen in 3 and 9 patients, respectively. CONCLUSIONS: This meta-analysis demonstrates that EIGB is a safe device offering an effective weight loss that warrants further studies for its long-term weight loss outcomes. Severe adverse events are rare, and the rate of early removal is low.

The Procedureless Elipse Gastric Balloon Program: Multicenter Experience in 1770 Consecutive Patients.

PURPOSE: The Elipse balloon is a novel, non-endoscopic option for weight loss. It is swallowed and filled with fluid. After 4 months, the balloon self-empties and is excreted naturally. Aim of the study was to evaluate safety and efficacy of Elipse balloon in a large, multicenter, population. MATERIALS AND METHODS: Data from 1770 consecutive Elipse balloon patients was analyzed. Data included weight loss, metabolic parameters, ease of placement, device performance, and complications. RESULTS: Baseline patient characteristics were mean age 38.8 ± 12, mean weight 94.6 ± 18.9 kg, and mean BMI 34.4 ± 5.3 kg/m2. Triglycerides were 145.1 ± 62.8 mg/dL, LDL cholesterol was 133.1 ± 48.1 mg/dL, and HbA1c was 5.1 ± 1.1%. Four-month results were WL 13.5 ± 5.8 kg, %EWL 67.0 ± 64.1, BMI reduction 4.9 ± 2.0, and %TBWL 14.2 ± 5.0. All metabolic parameters improved. 99.9% of patients were able to swallow the device with 35.9% requiring stylet assistance. Eleven (0.6%) empty balloons were vomited after residence. Fifty-two (2.9%) patients had intolerance requiring balloon removal. Eleven (0.6%) balloons deflated early. There were three small bowel obstructions requiring laparoscopic surgery. All three occurred in 2016 from an earlier design of the balloon. Four (0.02%) spontaneous hyperinflations occurred. There was one (0.06%) case each of esophagitis, pancreatitis, gastric dilation, gastric outlet obstruction, delayed intestinal balloon transit, and gastric perforation (repaired laparoscopically). CONCLUSION: The Elipse™ Balloon demonstrated an excellent safety profile. The balloon also exhibited remarkable efficacy with 14.2% TBWL and improvement across all metabolic parameters.

The safety and efficacy of the procedureless intragastric balloon.

BACKGROUND: Obesity is on a continuous rise worldwide, and with it, novel bariatric procedures have emerged. The introduction of gastric balloons has opened up a nonsurgical option for patients opting for it. However, they still require some form of sedation and endoscopy for insertion and/or removal. OBJECTIVES: The Elipse balloon is a novel creation that has managed to bypass both these procedures; therefore, the investigation into its effectiveness is of importance. SETTING: Royale Hayat, Sabah, and Amiri Hospitals, Kuwait. METHODS: This is a multicenter, prospective analysis of all patients who underwent the Elipse balloon insertion. For the duration of 4 months, weight, body mass index, and the occurrence of adverse events was documented. RESULTS: A total of 135 patients were included, with a mean age of 33.5 years. At the 4-month mark, the mean weight of the patients showed a drop of 13.0 kg (P = .000), and the mean body mass index showed a drop of 4.9 units (P = .000). The mean percent total weight loss was 15.1%. All patients reported nausea in the first day of insertion; however, 69.6% reported complete resolution by the third day. Two patients (1.5%) vomited the balloon early, 3 patients (2.2%) had to have the balloon removed early due to intolerance, 3 patients (2.2%) experienced early deflation, 18 (13.3%) patients reported episodes of diarrhea around the time of deflation, and 29 (21.5%) patients experienced colicky abdominal pain in the week of balloon deflation. One patient experienced small bowel obstruction after which the balloon was removed via laparoscopic enterotomy. CONCLUSION: This study aimed to evaluate the safety and effectiveness of the Elipse balloon in the largest population studied as of date. It was also able to demonstrate that it can be safely and successfully swallowed, filled, imaged, and passed. In addition, it effectively aided in weight loss, showing promising results.

Safety and Efficacy of a New Swallowable Intragastric Balloon Not Needing Endoscopy: Early Italian Experience.

PURPOSE: The aim of this study was to evaluate the safety and efficacy of a new intragastric balloon (Elipse™ Balloon, Allurion Technologies, Natick, MA USA) not needing endoscopy. MATERIALS AND METHODS: The balloon was swallowed under fluoroscopy in 38 consecutive patients (F/M 28/10, mean age 46.4 ± 10.6 years, mean weight 109.7 ± 21.9 kg, and mean body mass index (BMI) 38.6 ± 6.7 kg/m2). After 4 months, the balloon spontaneously emptied and it was excreted through the digestive tract without upper endoscopy. RESULTS: There were no complications during balloon passage. After 16 weeks, the mean weight loss was 12.7 kg, mean percent excess weight loss was 26%, and mean BMI reduction was 4.2 kg/m2. Total body weight loss was 11.6%. There was a significant reduction in major co-morbidities related to metabolic syndrome: blood pressure (p < 0.02), waist circumference (p < 0.002), triglycerides (p < 0.0001), blood glucose (p < 0.001), and HOMA-IR index (p < 0.001). At the end of the treatment, 37 balloons were naturally excreted in the stool, and one balloon was endoscopically removed. CONCLUSIONS: The results of this study on 38 consecutive patients demonstrate that the Elipse™ Balloon is safe, effective, and very well accepted by patients.

Laparoscopic management of a small bowel obstruction secondary to Elipse intragastric balloon migration: A case report.

INTRODUCTION: The Elipse™ intragastric balloon (IGB) for weight loss is a swallowable capsule that is filled with 550mL of fluid and resides in the stomach for four months before being excreted from the gastrointestinal tract. Although initial data showed that use of this device is safe and free from serious complications, we report for the first time the successful management of an Elipse™ IGB-related adverse event. PRESENTATION OF CASE: A 41-year-old woman presented to our emergency department following two days of abdominal pain, vomiting, and constipation. Her medical history included four caesarean sections and insertion of the Elipse™ IGB 16 weeks prior to presentation. The patient was vitally stable at presentation and abdominal examination revealed a mildly distended abdomen. Plain X-ray revealed a small bowel obstruction (SBO), and a double contrast computed tomography scan showed a dilated small bowel with mild free fluid proximal to a transition zone at the distal jejunum. Laparoscopic enterotomy was performed just proximal to the obstruction site, and the balloon was visualized and extracted after it had been incised and emptied. The enterotomy incision was closed with an intracorporeal continuous absorbable suture. The patient's recovery was uneventful and she was discharged on postoperative day 4. DISCUSSION: We discuss the possible etiologies of SBO following Elipse™ IGB insertion, and present a brief literature review regarding surgical and nonsurgical management options for such cases. CONCLUSION: Although initial data showed the Elipse™ IGB to be safe, complications can occur and be managed successfully.

A prospective pilot study of the efficacy and safety of Elipse intragastric balloon: A single-center, single-surgeon experience.

BACKGROUND: Elipse™ is the least invasive IGB for weight loss that needs no sedation or endoscopy. It is a swallowable capsule filled with 550 mL of fluid, which stays in the stomach for 16 weeks and is excreted from the gastrointestinal tract. Kuwait is one of the first countries to start using Elipse™ as a weight loss device. This study aims to evaluate the efficacy and safety of Elipse™ intragastric balloon (IGB). MATERIALS AND METHODS: This is a single-center prospective pilot study of 51 Elipse™ insertions at our clinic. The patients were followed for 4 months to monitor their weight and body mass index (BMI) at 1, 2, and 4 months. Total weight loss, % excess weight loss (%EWL), % total body weight loss (%TBWL), and change in BMI and waist circumference (WC) were recorded at the end of the study. A short survey was administered to evaluate symptoms, complications, and overall satisfaction. RESULTS: Fifty-one patients participated, of which five had Elipse™ removed because of intolerance. One case vomited the balloon; one had early deflation. The total weight loss was 8.84 kg, %TBWL 10.44%, %EWL 40.84%, change in BMI 3.42 kg/m2, and the total WC reduction 8.62 cm. Symptoms after insertion were severe, whereas those during excretion were mild and self-limiting. No serious complications were recorded, and the overall satisfaction was above average. CONCLUSION: Our data proves that Elipse™ is a safe and effective device for weight loss. Nevertheless, some limitations were observed that need to be overcome for better outcomes. Larger studies are needed to support our findings.

Measurement of waist circumference for retrospective studies - prospective validation of use of CT images to assess abdominal circumference.

INTRODUCTION: To validate the use of supine position and CT images for assessing abdominal circumference (AC). METHOD: A prospective study in consecutive patients undergoing scheduled abdominal CT at our center between 17 and 25 September 2012. AC was measured four times: Measurements 1 and 2 were sequentially done by the same trained nurse before abdominal CT just above the iliac crest, while measurements 3 and 4 were done on the last abdominal CT slice not showing the iliac bone. Student's t tests and Q-Q and Bland-Altman plots were used for statistical analysis. RESULTS: A total of 102 patients were recruited. Mean age, 60 (35-78) years. Mean BMI, 25 (18-39) kg/m(2). Mean AC, 93.2 (73-135) cm. No significant differences were found between the four ACs measured (Student's t test, P=0.83). Q-Q and Bland-Altman plots showed good overlapping for the low and central values (73-110 cm) with a greater scatter for extremely high values. For the ellipse estimation, R(2) was 0.987 with a mean error of 0.4 cm and a stretch dispersion between 1.1 and -0.3 cm. CONCLUSION: Supine (either measured or estimated on CT images by free hand elliptical ROI or ellipse formula) and standing measurements appear to be equivalent for abdominal circumferences <110 cm.

Aniseikonia secundaria a cirugías refractivas realizadas por lasik

Introducción: detectar la ocurrencia de Aniseikonia Meridional Horizontal en pacientes operados de cirugía refractiva por el sistema LASIK. Métodos: una muestra de 19 pacientes emetropizados por LASIK es comparada con una muestra de 20 pacientes naturalmente emétropes, con el objeto de estimar el efecto que los cambios de curvatura corneal tienen sobre el meridiano horizontal de la imagen retinal, teniendo en cuenta que las variaciones del poder óptico del ojo altera la posición del Punto Nodal, lo que a su vez altera el tamaño de la imagen retinal. Las ametropías preexistentes no fueron tomadas en cuenta. Para el estudio fue utilizado el Test Monocular de Merchán para detectar Aniseikonia (Merchán G. 2004): un elipsoide generado por computador incrementa su meridiano horizontal, contra orden dada, acercándose así a la figura de un círculo perfecto. El paciente activa el test y es instruido para detenerlo cuando considere que el elipsoide ha adquirido la forma de un círculo perfecto. En este momento el software compara los ejes horizontal y vertical de la figura resultante y muestra en porcentaje cualquier diferencia entre ellos; lo ideal es que el eje horizontal sea 100% igual al vertical, lo cual significa que la figura es realmente un círculo y así es percibido por el paciente, probando además que en el ojo examinado no existe ninguna Magnificación Meridional Horizontal. El ojo compañero es ahora sometido a la misma prueba y los resultados de los dos son comparados. Una diferencia entre ellos del 3% o superior (Borish, 1975) es considerada indicadora de Aniseikonia Meridional Horizontal. Resultados: los análisis estadísticos de proporciones, Z, tanto de una cola como de dos para el valor Z de diferencia entre proporciones, 36.8% de la primera muestra (emétropes por LASIK) y 5% de la segunda (naturalmente emétropes) es significativa, por lo cual se rechaza la hipótesis nula en favor de la alternativa. Conclusiones: la cirugía refractiva altera la curvatura corneal y consecuentemente la posición del Punto Nodal, lo cual puede causar una Aniseikonia Meridional Horizontal de grado bajo y asintomática aproximadamente en la tercera parte de los casos examinados.

Introduction: to detect the occurrence of Horizontal Meridional Aniseikonia in patients operated of refractive surgery with LASIK. Methods and materials: a sample of 19 patients made emmetropic by LASIK intervention is compared t a sample of 20 naturally emmetropic patients in order to asses the effect that changes in corneal curvature have over the horizontal meridian of the retinal image taking into account that variations of the optical power of the eye alters the position of the Nodal Point which in turn alters the size of the retinal image. Pre-existing ametropia was not specified or taken into account. Merchan Monocular Test for Aniseikonia was used for this study (Merchán G. 2004). A computer generated vertically elongated ellipsoid increases, upon command, the horizontal axis gradually approaching a perfect circle. The patient activates the test and is asked to stop the moment he or she considers that the ellipsoid has turned into a perfect circle. At this point the software compares the horizontal to the vertical axis of the resulting figure. Any difference between the axes is shown in percentage. Ideally, the horizontal axis should be 100% equal to the vertical axis which means that the figure is really a circle and is perceived as such by the patient, furthermore proving that no Horizontal Meridional Magnification is present in the eye under testing. The fellow eye is similarly tested and the results of the two eyes are compared. Differences above 3% (Borish, 1975) is considered indicative of the presence of Horizontal Meridional Aniseikonia. Results: statistical analyses for both one-tail and two-tails for the Z value for difference in proportions of the two groups show that 36.8% in the first group (emétropes by surgery) is statiscally significant from 5% in the second group (natural emmetropes), thus rejecting the null hypotheses. Conclusions:refractive surgery changes the corneal curvature and consequently the position of the Nodal Point all of which may cause a secondary asymptomatic low degree Horizontal Meridional Aniseikonia in approximately one third of the cases examined.

Objetivo: detectar a ocorrência de Aniseiconia Meridional Horizontal em pacientes operados de cirurgia refrativa pelo sistema LASIK. Métodos: uma amostra de 19 pacientes emetropes por LASIK é comparada a outra amostra de 20 pacientes naturalmente amétropes, com o objetivo de estimar o efeito que as mudanças de curvatura da córnea tem sobre o meridiano horizontal da imagem da retina, tendo em conta que as variações do poder ótico do olho altera a posição do Ponto Nodal, que, por sua vez, altera o tamanho da imagem na retina. As ametropías preexistentes não foram levadas em consideração. Para o estudo foi utilizado o Teste Monocular de Merchán para detectar Aniseiconia (Merchán G. 2004) Um elipsoide gerado por computador incrementa seu meridiano horizontal, contra ordem dada, aproximando-se assim à figura de um círculo perfeito. O paciente ativa o teste e é instruído para detê-lo quando considere que o elipsóide adquiriu a forma de um círculo perfeito. Neste momento, o software compara os eixos horizontal e vertical da figura resultante e mostra em porcentagem qualquer diferença entre eles. O ideal é que o eixo horizontal seja 100% igual ao vertical, o que significa que a figura é realmente um círculo e assim é percebido pelo paciente, provando ademais, que no olho examinado não existe nenhuma Magnificação Meridional Horizontal. O olho companheiro é agora submetido à mesma prova e os resultados dos dois são comparados em seguida. Uma diferença entre eles de 3% ou superior (Borish, 1975) é considerada indicadora de Aniseiconia Meridional Horizontal. Resultados: as análises estatísticas de proporções, Z, tanto de uma fila como de duas para o valor Z de diferença entre proporções, 36,8% da primeira amostra (emétropes por LASIK) e 5% da segunda (naturalmente emértropes) é significativa pelo qual se rejeita a hipótese nula em favor da alternativa. Conclusão: a cirurgia refrativa altera a curvatura corneal e consequentemente, a posição do Ponto Nodal, pela qual pode causar uma Aniseiconia Meridional Horizontal de baixo grau e assintomática em aproximadamente a terceira parte dos casos examinados.

Estimativas da qualidade de linhas poligonais topográficas / Quality estimations of topographical traverses

O objetivo deste artigo é descrever um procedimento que contribui com estimativas de qualidade de levantamento topográficos mediante a pré-análise e estimativas obtidas a partir de análise pós-ajustamento. As estimativas são dadas pelo teste qui-quadrado da forma quadrática do erro de fechamento, pelo teste qui-quadrado da forma quadrática dos resíduos obtidos no ajustamento pelo método dos mínimos quadrados, pelo teste data snooping de Baarda, pela elipse dos erros, pela elipse de confiança, pelo círculo do erro de posição e pelo círculo do erro médio. Estes conceitos são examinados por meio de valores numéricos no caso de uma linha poligonal simples implantada no campus da Universidade Federal de Santa Maria e medida com um taquímetro eletrônico.

The objective through this article is to describe a procedure that contributes with quality survey estimations by means pre-analysis survey and estimations by means post-adjustment. The estimations are given by the chi-square test of the quadratic form of misclosures, the chi-square of the quadratic form of residuals from the least-squares adjustment method, the Baarda's data snooping test, the standard ellipse, the confidence ellipse, position error circle and mean error circle. These concepts are examined through the numerical values provided in the case of a simple topographical traverse which was implanted at the Universidade Federal de Santa Maria Campus with electronic tachymeter.