Comparación de la refracción subjetiva binocular guiada por el sistema Chronos con la refracción subjetiva binocular hecha por un optometrista como Gold Standard

Introducción: Se comparó un nuevo equipo de refracción subjetiva binocular guiada (Chronos) con la refracción subjetiva realizada por un optometrista experimentado como Gold Standard. Material y métodos: Realizamos un estudio observacional transversal, aleatorizado y doble ciego en una muestra de 43 ojos derechos de pacientes, 24 hombres (55.8 %) y 19 mujeres (44.2 %) con una mediana de 54 años y rango intercuartílico (42-64). Los sujetos se seleccionaron mediante el criterio de inclusión de ausencia de patología ocular previa y los criterios de exclusión del equipo Chronos. Cada paciente fue graduado por el equipo Chronos, obteniendo una refracción subjetiva binocular y una agudeza visual para lejos y cerca, asistido por un optometrista. Los resultados refractivos se analizaron mediante equivalente esférico medio (M) y componentes cilíndricas y verticales y oblicuas (J0 y J45). Resultados: Se calcularon los coeficientes de correlación de Spearman para las variables M0, J0 y J45 entre el Chronos y el optometrista obteniendo una fuerte correlación positiva de 0.983, 0.804 y 0.777 respectivamente con una p<0.01 para las 3 en la refracción de lejos. Para la refracción de lejos los coeficientes fueron 0.973, 0.727 y 0.754 respectivamente para las mismas con una p<0.01. Las agudezas visuales obtuvieron una correlación positiva más baja para la refracción de lejos de 0.634 y p<0.01 y para refracción de cerca de 0.259 y p<0.05 siendo este último el único que resultó estadísticamente significativo. No hubo diferencias estadísticamente significativas entre hombres y mujeres ni en pacientes ≥40 años. Conclusiones: La refracción subjetiva binocular guiada por el Equipo Chronos muestra unos valores muy similares a la refracción realizada por un optometrista tanto el componentes esféricos y cilíndricos como en agudeza visual excepto en la visión de cerca donde las diferencias son estadísticamente significativas.Introduction: A new binocular-guided subjective refraction device (Chronos) was compared with subjective refraction performed by an experienced optometrist as the Gold Standard. Material and methods: We conducted a cross-sectional, randomized, double-blind observational study in a sample of 43 patients’ right eyes, 24 men (55.8%) and 19 women (44.2%) with a median of 54 years and interquartile range (42-64). The subjects were selected using the inclusion criteria of the absence of previous ocular pathology and the exclusion criteria of the Chronos system. Each patient was graded by the Chronos team, obtaining subjective binocular refraction and visual acuity for far and near, assisted by an optometrist. Refractive results were analyzed by mean spherical equivalent (M) and cylindrical and vertical and oblique components (J0 and J45). Results: Spearman's correlation coefficients were calculated for the variables M0, J0 and J45 between the Chronos and the optometrist, obtaining a strong positive correlation of 0.983, 0.804 and 0.777, respectively, with p<0.01 for the 3 in distance refraction. For distance refraction, the coefficients were 0.973, 0.727 and 0.754, respectively, with p<0.01. Visual acuity obtained a lower positive correlation for distance refraction of 0.634 and p<0.01 and for near refraction of 0.259 and p<0.05, the latter being the only one that was statistically significant. There were no statistically significant differences between men and women or in patients ≥40 years. Conclusions: The subjective binocular refraction guided by the Chronos device shows very similar values to the refraction performed by an optometrist, both in the spherical and cylindrical components and in visual acuity, except in near vision where the differences are statistically significant

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements