RESUMEN

Most persons with obesity who have undergone gastric bypass surgery present depressive symptoms. Depression and anxiety have been associated with tear film disorders. This study aimed to investigate whether there is a correlation between tear film conditions and depression symptoms in patients subjected to bariatric surgery. The participants completed a Patient Health Questionnaire to detect depression symptoms. The break-up time and Schirmer test were subsequently applied; the measurements were performed three times, and the average time was subsequently recorded. The results revealed that the Schirmer test score and PH-9 score were negatively correlated, but this was not the case for the break-up time test. Depression symptoms may correlate with lower tear production from the principal tear gland, but they may not have the same effect on meibomian gland production in adults undergoing bariatric surgery. In addition to routine control, bariatric surgery patients should be periodically evaluated by an ophthalmologist and/or psychologist who is aware of potential comorbidities. Furthermore, the observed association between depression symptoms and tear deficiencies highlights the importance of further investigations to gain a better understanding of these mechanisms.

RESUMEN

RESUMEN Objetivo: Comparar la sensibilidad al contraste evaluada en un grupo de mexicanos con diabetes mellitus contra uno sin diabetes como control. Métodos: Un total de 31 voluntarios, 14 participantes con DM con un tiempo de diagnóstico entre 2 y 20 años (sin retinopatía diabética), y 17 en el grupo control iniciaron el estudio; 4 diabéticos y 5 no diabéticos fueron excluidos por no cumplir con los criterios de inclusión. Por lo tanto, los datos analizados fueron de un grupo de 10 diabéticos (52 ± 10 años) y otro de 12 no diabéticos (52 ± 6 años). Se evaluó la sensibilidad al contraste con la cartilla Vector Vision CSV1000E a una distancia de 2,5 metros con una iluminación de 85 cd/m2. Resultados: Un mayor porcentaje de ojos diabéticos alcanzaron un mejor umbral de contraste en 3, 6 y 18 ciclos por grado en comparación con el grupo control. En 12 ciclos por grado solamente en los umbrales 1 y 5. Conclusiones: La sensibilidad al contraste de la población mexicana con diabetes mellitus presenta mejor percepción de contraste en las frecuencias evaluadas que el grupo control(AU)

ABSTRACT Objective: Compare contrast sensitivity as measured in a group of Mexican diabetes mellitus patients versus a control non-diabetic group. Methods: A group of 31 volunteers, 14 participants with DM with a diagnosis time between 2 and 20 years (without diabetic retinopathy), and 17 in the control group started the study; 4 diabetics and 5 non-diabetics were excluded because they did not meet the inclusion criteria. Therefore, the data analyzed were from a group of 10 diabetics (52 ± 10 years) and another of 12 non-diabetics (52 ± 6 years). Contrast sensitivity was evaluated with a Vector Vision CSV1000E chart at a distance of 2.5 meters and a luminance of 85 cd/m2. Results: A higher percentage of diabetic eyes reached a better contrast threshold at 3, 6 and 18 cycles per degree in comparison with the control group. At 12 cycles per degree only at thresholds 1 and 5. Conclusions: Contrast sensitivity in the Mexican population with diabetes mellitus displays better contrast perception at the frequencies evaluated than the control group(AU)

Asunto(s)

RESUMEN

Bariatric surgery patients have deficiencies of macro- and micronutrients that may be related to ophthalmic complications, for example consequences on tear film layers (lipid, aqueous, and mucosa). In this work, we associated protein diet and tear film layers in bariatric patients of a Mexican hospital. We measured characteristics of tear film by the Schirmer and tear break up time (TBUT) tests under three different protein percentage diets: 10, 15, and 25%. TBUT values were low in our study, and therefore, bariatric patients may have high possibilities to suffer dry eye or modifications in lipid tear layer. Bariatric patients, additional to the routine control, periodically should have an extensive eye examination.

Asunto(s)

RESUMEN

We introduce a simple method to characterize the topological charge associated with the orbital angular momentum of a m-order elliptic light beam. This method consists in the observation of the far field pattern of the beam carrying orbital angular momentum, diffracted from a triangular aperture. We show numerically and experimentally, for Mathieu, Ince-Gaussian, and vortex Hermite-Gaussian beams, that only isosceles triangular apertures allow us to determine in a precise and direct way, the magnitude m of the order and the number and sign of unitary topological charges of isolated vortices inside the core of these beams.

RESUMEN

We show that propagation of optical beams in periodic lattices induces power oscillations between the Fourier spectrum peaks, with the indices related by the Bragg resonance condition. In the spatial coordinates, this is reflected in the beam position oscillations. A simple resonant theory explains the phenomenon. The effect can be used for controlled generation of the Floquet-Bloch modes in photonic lattices.

RESUMEN

A new experimental setup is demonstrated to produce high-order Bessel beams. It is based on the field decomposition of the Bessel beam into its even and odd field components. The implementation is performed over the spectral components with a Mach-Zehnder interferometer that synthesizes the components into the desired Bessel beam. The main advantage of our setup is that the required annular transmittances have only discrete phase changes of pi radians instead of a continuous change of phase.

RESUMEN

It is shown that three-dimensional nonparaxial beams are described by the oblate spheroidal exact solutions of the Helmholtz equation. For what is believed to be the first time, their beam behavior is investigated and their corresponding parameters are defined. Using the fact that the beam width of the family of paraxial Gaussian beams is described by a hyperbola, we formally establish the connection between the physical parameters of nonparaxial spheroidal beam solutions and those of paraxial beams. These results are also helpful for investigating exact vector nonparaxial beams.

RESUMEN

We demonstrate the existence of parabolic beams that constitute the last member of the family of fundamental nondiffracting wave fields and determine their associated angular spectrum. Their transverse structure is described by parabolic cylinder functions, and contrary to Bessel or Mathieu beams their eigenvalue spectrum is continuous. Any nondiffracting beam can be constructed as a superposition of parabolic beams, since they form a complete orthogonal set of solutions of the Helmholtz equation. A novel class of traveling parabolic waves is also introduced for the first time.