OCT applications in contact lens fitting.

Optical Coherence Tomography (OCT) is a noninvasive, high-speed, high-resolution imaging technology based in the Michaelson interferometry. A near-infrared light beam is used to register the intensity variations for the light backscattered on each sample layer. Due to the high repeatability on corneal measurements, spectral domain OCT (SD-OCT) is the gold standard when talking about in vivo, non-invasive anterior segment imaging. Changes in the morphology of various ocular surfaces such as the cornea, conjunctiva, limbus or tear film with soft (SCL), rigid, corneal or scleral lens (SL) wear can be described by OCT measurements. For instance, evaluation of the corneoscleral region is essential on SL fitting. For orthokeratology lenses central epithelial thinning and peripheral thickening and their regression could be quantified with OCT after Ortho-K lens wear. Blood vessel compression on the landing zone as well as vault thickness and fluid reservoir (FR) turbidity could be imaged with OCT. Tear film evaluation on contact lens wearers is essential because its use could lead to variations on the biochemical components in tears. Changes in tear meniscus dynamics and several parameters such as volume (TMV), tear meniscus height (HMT) and turbidity could be determined with OCT and positively correlated with the instillation of different ophthalmic solutions with Non-Invasive Break Up Time (NIBUT) and Schirmer test values. This manuscript shows the increasing applicability of OCT technology for the in vivo characterization of contact lens fitting and interaction with the ocular surface in a faster, safer and non-invasive way. Future research will still allow exploring OCT imaging to its full potential in contact lens practice, as there is still a significant amount of information contained in the images that are not yet easy to extract, analyze and give clinical value.

Modelling pool testing for SARS-CoV-2: addressing heterogeneity in populations.

Amplifying the testing capacity and making better use of testing resources is a crucial measure when fighting any pandemic. A pooled testing strategy for SARS-CoV-2 has theoretically been shown to increase the testing capacity of a country, especially when applied in low prevalence settings. Experimental studies have shown that the sensitivity of reverse transcription-polymerase chain reaction is not affected when implemented in small groups. Previous models estimated the optimum group size as a function of the historical prevalence; however, this implies a homogeneous distribution of the disease within the population. This study aimed to explore whether separating individuals by age groups when pooling samples results in any further savings on test kits or affects the optimum group size estimation compared to Dorfman's pooling, based on historical prevalence. For this evaluation, age groups of interest were defined as 0-19 years, 20-59 years and over 60 years old. Generalisation of Dorfman's pooling was performed by adding statistical weight to the age groups based on the number of confirmed cases and tests performed in the segment. The findings showed that when the pooling samples are based on age groups, there is a decrease in the number of tests per subject needed to diagnose one subject. Although this decrease is minuscule, it might account for considerable savings when applied on a large scale. In addition, the savings are considerably higher in settings where there is a high standard deviation among the positivity rate of the age segments of the general population.

Limitación del esfuerzo terapéutico en cuidados intensivos pediátricos: conocimiento y actitudes bioéticas del profesional médico / Limitation of therapeutic effort in Paediatric Intensive Care Units: bioethical knowledge and attitudes of the medical profession

Los cuidados intensivos pediátricos son una especialidad nueva, con importantes avances tecnológicos que pueden prolongar el proceso de morir. Uno de los problemas bioéticos frecuentes es la limitación del esfuerzo terapéutico, que es la adecuación y/o proporcionalidad del tratamiento tratando de evitar obstinación y futilidad. OBJETIVO Conocer la experiencia de médicos que trabajan en unidades de cuidado intensivo (UCIP) ante decisiones ético-clínicas. SUJETOS Y MÉTODO Estudio observacional, descriptivo y transversal, aplicando una encuesta anónima a médicos de UCIP, solicitando datos sobre problemas éticos que se generan en la atención al niño crítico y su procedimiento de resolución. Aprobado por el Comité de Ética de la Investigación de la Facultad de Medicina de la Universidad del Desarrollo-Clínica Alemana. RESULTADOS Respondieron 126 médicos de 34 UCIP de Chile. El 98,41% ha tomado decisiones de limitación terapéutica. El tipo de limitación más frecuente mencionado fue la orden de no reanimar (n = 119), seguido por la no instauración de medicamentos (n = 113), limitación de ingreso a UCIP (n = 81), siendo la menos mencionada la retirada de tratamientos (n = 81). El 34,13% consideró que existían diferencias éticas entre no instaurar o retirar un determinado tratamiento. CONCLUSIONES Los dilemas ético-clínicos son comunes en la UCIP, siendo frecuentes las decisiones de limitación terapéutica. Muchos médicos reconocen no poseer conocimientos en ética clínica y necesitar formación continua en bioética.

Paediatric intensive care is a relatively new specialty, with significant technological advances that lead to the prolongation of the dying process. One of the most common bioethical problems is limitation of treatment, which is the adequacy and/or proportionality treatment, trying to avoid obstinacy and futility. OBJECTIVE To determine the experience of physicians working in Paediatric Intensive Care Units (PICU) when faced with bioethical decisions. SUBJECTS AND METHOD An observational, descriptive and cross-sectional study was conducted using an anonymous questionnaire sent to physicians working in PICU. The data requested was related to potential ethical problems generated in the care of the critical child, and the procedure for their resolution. The study was approved by the Ethics Research Committee of the Faculty of Medicine UDD CAS. RESULTS A total of 126 completed questionnaires were received from physicians working in 34 PICU in Chile. Almost all (98.41%) of them acknowledged having taken therapeutic limitation decisions (TLD). The most common type of TLD mentioned was the Do Not Resuscitate order (n = 119), followed by the establishment of no medications (n = 113), limited admission to PICU (n = 81), with the withdrawal of treatment being the least mentioned (n = 81). Around one-third (34.13%) felt that there were no ethical difference between introducing or removing certain treatments. CONCLUSIONS Bioethical dilemmas are common in the PICU, with therapeutic limitation decisions being frequent. Many recognise not having expertise in clinical ethics, and they need continuing education in bioethics.

[Limitation of therapeutic effort in Paediatric Intensive Care Units: Bioethical knowledge and attitudes of the medical profession]. / Limitación del esfuerzo terapéutico en cuidados intensivos pediátricos: conocimiento y actitudes bioéticas del profesional médico.

UNLABELLED: Paediatric intensive care is a relatively new specialty, with significant technological advances that lead to the prolongation of the dying process. One of the most common bioethical problems is limitation of treatment, which is the adequacy and/or proportionality treatment, trying to avoid obstinacy and futility. OBJECTIVE: To determine the experience of physicians working in Paediatric Intensive Care Units (PICU) when faced with bioethical decisions. SUBJECTS AND METHOD: An observational, descriptive and cross-sectional study was conducted using an anonymous questionnaire sent to physicians working in PICU. The data requested was related to potential ethical problems generated in the care of the critical child, and the procedure for their resolution. The study was approved by the Ethics Research Committee of the Faculty of Medicine UDD CAS. RESULTS: A total of 126 completed questionnaires were received from physicians working in 34 PICU in Chile. Almost all (98.41%) of them acknowledged having taken therapeutic limitation decisions (TLD). The most common type of TLD mentioned was the Do Not Resuscitate order (n=119), followed by the establishment of no medications (n=113), limited admission to PICU (n=81), with the withdrawal of treatment being the least mentioned (n=81). Around one-third (34.13%) felt that there were no ethical difference between introducing or removing certain treatments. CONCLUSIONS: Bioethical dilemmas are common in the PICU, with therapeutic limitation decisions being frequent. Many recognise not having expertise in clinical ethics, and they need continuing education in bioethics.