Asociación entre obesidad abdominal, consumo de alcohol y actividad física en universitarios panameños / Association between abdominal obesity, alcohol consumption and physical activity in Panamanian college students

Introducción. La obesidad abdominal es considerada un factor de riesgo de enfermedad cardiovascular y diabetes. El consumo excesivo episódico de alcohol y la inactividad física también son factores de riesgo comportamentales asociados a enfermedades no transmisibles. Objetivo: Analizar la asociación entre la obesidad abdominal, el consumo de alcohol y la inactividad física en universitarios panameños. Materiales y métodos: Estudio transversal analítico realizado en 374 estudiantes universitarios panameños en el periodo abril ­ diciembre de 2021. Se implementó el cuestionario para la vigilancia de factores de riesgo de enfermedades no transmisibles de la Organización Mundial de la Salud y se evaluó la circunferencia de cintura. La obesidad abdominal se estableció con una circunferencia de cintura ≥80 cm en mujeres y ≥90 cm en hombres. Se realizaron análisis descriptivos, bivariados y múltiples usando modelos de regresión logística para determinar la asociación entre las variables del estudio. Las pruebas U Mann-Whitney y Chi cuadrado fueron utilizadas para analizar diferencias por sexo. Resultados: Una tercera parte de los universitarios participantes presentaron obesidad abdominal. Las mujeres reportaron mayores niveles de inactividad física (<0,0001) y conducta sedentaria (p=0,0010) que los hombres. Después de ajustar por sexo, edad y nivel socioeconómico, la obesidad abdominal estuvo asociada con la inactividad física (OR: 1,762, IC 95%: 1,040 ­ 2,985, p=0,035) y el consumo excesivo episódico de alcohol (OR 1,114, IC: 1,015 ­ 1,223, p=0,023). Conclusiones: Los universitarios panameños que reportaron bajos niveles de actividad física y consumo excesivo episódico de alcohol tuvieron una mayor probabilidad de registrar obesidad abdominal(AU)

Introduction. Abdominal obesity is considered a risk factor for cardiovascular disease and diabetes. Episodic excessive consumption of alcohol and physical inactivity are behavioral risk factors associated with non-communicable diseases. Objective: To analyze the association between abdominal obesity, alcohol consumption and physical inactivity in Panamanian university students. Materials and methods: Analytical cross-sectional study conducted on 374 Panamanian university students in the period April ­ December 2021. The questionnaire for the surveillance of risk factors for non-communicable diseases of the World Health Organization was implemented and waist circumference was evaluated. Abdominal obesity was established with a waist circumference ≥80 cm in women and ≥90 cm in men. Descriptive, bivariate, and multiple analyzes were performed using logistic regression models to determine the association between the study variables. The Mann-Whitney U and Chi square tests were used to analyze differences by sex. Results: A third of the participating university students had abdominal obesity. Women reported higher levels of physical inactivity (<0,0001) and sedentary behavior (p=0,0010) than men. After adjusting for sex, age and socioeconomic status, abdominal obesity was associated with physical inactivity (OR: 1,762, 95% CI: 1,040 ­ 2,985, p=0,035) and episodic heavy alcohol consumption (OR 1,114, CI: 1,015 ­ 1,223, p=0,023). Conclusions: Students who reported low levels of physical inactivity and binge drinking were more likely to have abdominal obesity(AU)

Balance of corneal horizontal coma by internal optics in eyes with intraocular artificial lenses: evidence of a passive mechanism.

It is well known that the aberrations of the cornea are partially compensated by the aberrations of the internal optics of the eye (primarily the crystalline lens) in young subjects. This effect has been found not only for the spherical aberration, but also for horizontal coma. It has been debated whether the compensation of horizontal coma is the result of passive mechanism [Artal, P., Benito, A., & Tabernero, J. (2006). The human eye is an example of robust optical design. Journal of Vision, 6 (1), 1-7] or through an active developmental feedback process [Kelly, J. E., Mihashi, T., & Howland, H. C. (2004). Compensation of corneal horizontal/vertical astigmatism, lateral coma, and spherical aberration by internal optics of the eye. Journal of Vision, 4 (4), 262-271]. In this study we investigate the active or passive nature of the horizontal coma compensation using eyes with artificial lenses, where no active developmental process can be present. We measured total and corneal aberrations, and lens tilt and decentration in a group of 38 eyes implanted with two types of intraocular lenses designed to compensate the corneal spherical aberration of the average population. We found that spherical aberration was compensated by 66%, and horizontal coma by 87% on average. The spherical aberration is not compensated at an individual level, but horizontal coma is compensated individually (coefficients of correlation corneal/internal aberration: -0.946, p<0.0001). The fact that corneal (but not total) horizontal coma is highly correlated with angle lamda (computed from the shift of the 1st Purkinje image from the pupil center, for foveal fixation) indicates that the compensation arises primarily from the geometrical configuration of the eye (which generates horizontal coma of opposite signs in the cornea and internal optics). The amount and direction of tilts and misalignments of the lens are comparable to those found in young eyes, and on average tend to compensate (rather than increase) horizontal coma. Computer simulations using customized model eyes and different designs of intraocular lenses show that, while not all designs produce a compensation of horizontal coma, a wide range of aspheric biconvex designs may produce comparable compensation to that found in young eyes with crystalline lenses, over a relatively large field of view. These findings suggest that the lens shape, gradient index or foveal location do not need to be fine-tuned to achieve a compensation of horizontal coma. Our results cannot exclude a fine-tuning for the orientation of the crystalline lens, since cataract surgery seems to preserve the position of the capsule.

Change in corneal aberrations after cataract surgery with 2 types of aspherical intraocular lenses.

PURPOSE: To study the effect of cataract surgery through 3.2 mm superior incisions on corneal aberrations with 2 types of monofocal intraocular lenses (IOLs) with an aspherical design. SETTING: Instituto de Optica, Consejo Superior de Investigaciones Científicas, and Fundación Jiménez Díaz, Madrid, Spain. METHODS: Corneal topography of 43 eyes was obtained before and after small corneal incision cataract surgery. Twenty-two eyes had implantation of a Tecnis Z9000 silicone IOL (Advanced Medical Optics) and 21 had implantation of an AcrySof IQ SN60WF acrylic IOL (Alcon Research Labs) using the recommended injector for each IOL type. The intended incision size (3.2 mm) was similar in the 2 groups. Corneal aberrations were estimated using custom-developed algorithms (based on ray tracing) for 10.0 mm and 5.0 mm pupils. Comparisons between preoperative and postoperative measurements and across the groups were made for individual Zernike terms and root-mean-square (RMS) wavefront error. RESULTS: The RMS (excluding tilt and defocus) did not change in the AcrySof IQ group and increased significantly in the Tecnis group with the 10.0 mm and 5.0 mm pupil diameters. Spherical aberration and coma-like terms did not change significantly; however, vertical astigmatism, vertical trefoil, and vertical tetrafoil changed significantly with surgery with the 10.0 mm and 5.0 mm pupil diameters (P<.0005). The induced wave aberration pattern for 3rd- and higher-order aberrations consistently showed a superior lobe, resulting from a combination of positive vertical trefoil (Z(3)(-3)) and negative tetrafoil (Z(4)(4)). The mean vertical astigmatism increased by 2.47 microm +/- 1.49 (SD) and 1.74 +/- 1.44 microm, vertical trefoil increased by 1.81 +/- 1.19 microm and 1.20 +/- 1.34 microm, and tetrafoil increased by -1.10 +/- 0.78 microm and -0.89 +/- 0.68 microm in the Tecnis group and AcrySof IQ group, respectively. There were no significant differences between the corneal aberrations in the 2 postoperative groups, although there was a tendency toward more terms or orders changing statistically significantly in the Tecnis group, which had slightly higher amounts of induced aberrations. CONCLUSIONS: Cataract surgery with a small superior incision induced consistent and significant changes in several corneal Zernike terms (vertical astigmatism, trefoil, and tetrafoil), resulting in a significantly increased overall corneal RMS wavefront error. These results can be used to improve predictions of optical performance with new IOL designs using computer eye models and identify the potentially different impact of incision strategies on cataract surgery.

Optical aberrations in the mouse eye.

PURPOSE: The mouse eye is a widely used model for retinal disease and has potential to become a model for myopia. Studies of retinal disease will benefit from imaging the fundus in vivo. Experimental models of myopia often rely on manipulation of the visual experience. In both cases, knowledge of the optical quality of the eye, and in particular, the retinal image quality degradation imposed by the ocular aberrations is essential. In this study, we measured the ocular aberrations in the wild type mouse. METHODS: Twelve eyes from six four-week old black C57BL/6 wild type mice were studied. Measurements were done on awake animals, one being also measured under anesthesia for comparative purposes. Ocular aberrations were measured using a custom-built Hartmann-Shack system (using 680-nm illumination). Wave aberrations are reported up to fourth order Zernike polynomials. Spherical equivalent and astigmatism were obtained from the 2nd order Zernike terms. Modulation Transfer Functions (MTF) were estimated for the best focus, and through-focus, to estimate depth-of-focus. All reported data were for 1.5-mm pupils. RESULTS: Hartmann-Shack refractions were consistently hyperopic (10.12+/-1.41 D, mean and standard deviation) and astigmatism was present in many of the eyes (3.64+/-3.70 D, on average). Spherical aberration was positive in all eyes (0.15+/-0.07 microm) and coma terms RMS were significantly high compared to other Zernike terms (0.10+/-0.03 microm). MTFs estimated from wave aberrations show a modulation of 0.4 at 2c/deg, for best focus (and 0.15 without cancelling the measured defocus). For that spatial frequency, depth-of-focus estimated from through-focus modulation data using the Rayleigh criterion was 6D. Aberrations in the eye of one anesthetized mouse were higher than in the same eye of the awake animal. CONCLUSIONS: Hyperopic refractions in the mouse eye are consistent with previous retinoscopic data. The optics of the mouse eye is far from being diffraction-limited at 1.5-mm pupil, with significant amounts of spherical aberration and coma. However, estimates of MTFs from wave aberrations are higher than previously reported using a double-pass technique, resulting in smaller depth-of-field predictions. Despite the large degradation imposed by the aberrations these are lower than the amount of aberrations typically corrected by available correction techniques (i.e., adaptive optics). On the other hand, aberrations do not seem to be the limiting factor in the mouse spatial resolution. While the mouse optics are much more degraded than in other experimental models of myopia, its tolerance to large amounts of defocus does not seem to be determined entirely by the ocular aberrations.

Accommodation response to Chinese and Latin characters in Chinese-illiterate young adults.

BACKGROUND: Differences in accommodation when reading Chinese, as compared to Latin, characters have been suggested to have a role in the higher prevalence of myopia in some Asian countries. Yeo and colleagues (Optom Vis Sci 2013; 90: 156-163) found that, in Chinese-literate children, accommodation was marginally more accurate (by less than 0.05 D), when reading Chinese text. This was attributed to the additional cognitive demand associated with interpreting the more complex Chinese symbols. The present study compared responses to single Chinese and Latin characters, while controlling for cognitive demand. METHODS: The monocular accommodative response was measured in Chinese-illiterate adults (10 emmetropes, mean spherical equivalent: -0.07 ± 0.42 D, age: 29.9 ± 4.2 years; 11 myopes, mean spherical equivalent: -4.28 ± 2.84 D, age: 31.7 ± 4.6 years) with an open-field autorefractor. Four Chinese and three Latin characters (approximately 1.15 degrees subtense) were individually presented on a display screen one metre away from the subject, while their vergence was varied over the range zero to 5.00 D using spectacle trial lenses. The slope and the accommodative error index (AEI) were calculated from the accommodative stimulus/response curves (ASRC). RESULTS: No statistically significant differences were found between refractive groups or among characters within the same refractive group in ARSC slopes (Latin: 0.87 ± 0.14 for myopes versus 0.81 ± 0.12 for emmetropes; Chinese: 0.84 ± 0.12 for myopes versus 0.85 ± 0.12 for emmetropes). No significant differences were found between characters in accommodative error index either (Latin, 0.78 ± 0.42 D for myopes versus 1.15 ± 0.72 D for emmetropes; Chinese, 0.74 ± 0.37 D for myopes versus 1.17 ± 0.83 D for emmetropes). However, accommodative error indices and accommodative errors were significantly higher for emmetropes. CONCLUSION: Under controlled cognitive demand, Chinese and Latin characters elicited similar responses in both individual refractive groups. This study fails to support the hypothesis that development of myopia in some Asian populations is associated with larger lags of accommodation when reading or viewing Chinese characters.

Total and corneal optical aberrations induced by laser in situ keratomileusis for hyperopia.

PURPOSE: To evaluate changes induced by standard laser in situ keratomileusis (LASIK) for hyperopia on total and corneal optical quality. METHODS: Total and corneal aberrations were measured before and after standard hyperopic LASIK in 13 eyes (preoperative spherical equivalent refractive error +3.17 +/- 1.10 D). The Chiron Technolas 217C laser with PlanoScan was used. Total aberrations (measured using laser ray tracing) and corneal aberrations (estimated from a videokeratoscope) were described using Zernike terms. Root-mean-square wavefront error for both total and corneal aberrations, and through-focus Strehl ratio for the point spread function of the whole eye were used to assess optical changes induced by surgery. RESULTS: Third and higher order aberrations increased significantly after hyperopic LASIK (by a factor of 2.20 for total and 1.78 for corneal aberrations, for a 6.5-mm pupil). Spherical aberration changed to negative values (corneal average decreased by -0.85 +/- 0.48 microm and total average by -0.70 +/- 0.30 microm). Best Strehl ratio for the whole eye decreased by a factor of 1.84. Hyperopic LASIK induced larger changes than myopic LASIK, compared to an equivalent group of myopic eyes from a previous study. Induced corneal spherical aberration was six times larger after hyperopic LASIK, for a similar range of correction, and of opposite sign. As with myopic LASIK, changes in internal spherical aberration are of opposite sign to those induced on the corneal anterior surface. CONCLUSIONS: Hyperopic LASIK induced significant amounts of aberrations. The largest increase occurred in spherical aberration, which showed a shift (toward negative values) of opposite sign; increase was greater than for myopic LASIK.

Myopic versus hyperopic eyes: axial length, corneal shape and optical aberrations.

This study investigated differences in geometrical properties and optical aberrations between a group of hyperopes and myopes (age-matched 30.3+/-5.2 and 30.5+/-3.8 years old, respectively, and with similar absolute refractive error 3.0+/-2.0 and -3.3+/-2.0, respectively). Axial length (AL) was measured by means of optical biometry, and corneal apical radius of curvature (CR) and asphericity (Q) were measured by fitting corneal topography data to biconic surfaces. Corneal aberrations were estimated from corneal topography by means of virtual ray tracing, and total aberrations were measured using a laser ray tracing technique. Internal aberrations were estimated by subtracting corneal from total aberrations. AL was significantly higher in myopes than in hyperopes and AL/CR was highly correlated with spherical equivalent. Hyperopic eyes tended to have higher (less negative) Q and higher total and corneal spherical aberration than myopic eyes. RMS for third-order aberrations was also significantly higher for the hyperopic eyes. Internal aberrations were not significantly different between the myopic and hyperopic groups, although internal spherical aberration showed a significant age-related shift toward less negative values in the hyperopic group. For these age and refraction ranges, our cross-sectional results do not support evidence of relationships between emmetropization and ocular aberrations. Our results may be indicative of presbyopic changes occurring earlier in hyperopes than in myopes.

In vivo chromatic aberration in eyes implanted with intraocular lenses.

PURPOSE: To measure in vivo and objectively the monochromatic aberrations at different wavelengths, and the chromatic difference of focus between green and infrared wavelengths in eyes implanted with two models of intraocular lenses (IOL). METHODS: EIGHTEEN EYES PARTICIPATED IN THIS STUDY: nine implanted with Tecnis ZB99 1-Piece acrylic IOL and nine implanted with AcrySof SN60WF IOL. A custom-developed laser ray tracing (LRT) aberrometer was used to measure the optical aberrations, at 532 nm and 785 nm wavelengths. The monochromatic wave aberrations were described using a fifth-order Zernike polynomial expansion. The chromatic difference of focus was estimated as the difference between the equivalent spherical errors corresponding to each wavelength. RESULTS: Wave aberration measurements were highly reproducible. Except for the defocus term, no significant differences in high order aberrations (HOA) were found between wavelengths. The average chromatic difference of focus was 0.46 ± 0.15 diopters (D) in the Tecnis group, and 0.75 ± 0.12 D in the AcrySof group, and the difference was statistically significant (P < 0.05). Chromatic difference of focus in the AcrySof group was not statistically significantly different from the Longitudinal chromatic aberration (LCA) previously reported in a phakic population (0.78 ± 0.16 D). The impact of LCA on retinal image quality (measured in terms of Strehl ratio) was drastically reduced when considering HOA and astigmatism in comparison with a diffraction-limited eye, yielding the differences in retinal image quality between Tecnis and AcrySof IOLs not significant. CONCLUSIONS: LRT aberrometry at different wavelengths is a reproducible technique to evaluate the chromatic difference of focus objectively in eyes implanted with IOLs. Replacement of the crystalline lens by the IOL did not increase chromatic difference of focus above that of phakic eyes in any of the groups. The AcrySof group showed chromatic difference of focus values very similar to physiological values in young eyes.

Effect of sampling on real ocular aberration measurements.

The minimum number of samples necessary to fully characterize the aberration pattern of the eye is a question under debate in the clinical as well as the scientific community. We performed repeated measurements of ocular aberrations in 12 healthy nonsurgical human eyes and in 3 artificial eyes, using different sampling patterns (hexagonal, circular, and rectangular with 19 to 177 samples, and 3 radial patterns with 49 sample coordinates corresponding to zeros of the Albrecht, Jacobi, and Legendre functions). For each measurement set we computed two different metrics based on the root-mean-square (RMS) of difference maps (RMS_Diff) and the proportional change in the wavefront (W%). These metrics are used to compare wavefront estimates as well as to summarize results across eyes. We used computer simulations to extend our results to "abnormal eyes" (keratoconic, post-LASIK, and post-radial keratotomy eyes). We found that the spatial distribution of the samples can be more important than the number of samples for both our measured as well as our simulated "abnormal" eyes. Experimentally, we did not find large differences across patterns except, as expected, for undersampled patterns.

Ocular aberrations with ray tracing and Shack-Hartmann wave-front sensors: does polarization play a role?

Ocular aberrations were measured in 71 eyes by using two reflectometric aberrometers, employing laser ray tracing (LRT) (60 eyes) and a Shack-Hartmann wave-front sensor (S-H) (11 eyes). In both techniques a point source is imaged on the retina (through different pupil positions in the LRT or a single position in the S-H). The aberrations are estimated by measuring the deviations of the retinal spot from the reference as the pupil is sampled (in LRT) or the deviations of a wave front as it emerges from the eye by means of a lenslet array (in the S-H). In this paper we studied the effect of different polarization configurations in the aberration measurements, including linearly polarized light and circularly polarized light in the illuminating channel and sampling light in the crossed or parallel orientations. In addition, completely depolarized light in the imaging channel was obtained from retinal lipofuscin autofluorescence. The intensity distribution of the retinal spots as a function of entry (for LRT) or exit pupil (for S-H) depends on the polarization configuration. These intensity patterns show bright corners and a dark area at the pupil center for crossed polarization, an approximately Gaussian distribution for parallel polarization and a homogeneous distribution for the autofluorescence case. However, the measured aberrations are independent of the polarization states. These results indicate that the differences in retardation across the pupil imposed by corneal birefringence do not produce significant phase delays compared with those produced by aberrations, at least within the accuracy of these techniques. In addition, differences in the recorded aerial images due to changes in polarization do not affect the aberration measurements in these reflectometric aberrometers.

On-eye measurement of optical performance of rigid gas permeable contact lenses based on ocular and corneal aberrometry.

PURPOSE: Our aim was to obtain a complete description of the interactions of rigid gas permeable (RGP) contact lenses with the optics of normal eyes. METHODS: We measured total and anterior-surface aberrations in four subjects, who were all long-term RGP contact lens wearers. The anterior-surface wave aberration was obtained from videokeratographic elevation maps, and ocular wave aberration was measured with a laser ray-tracing technique. Measurements were performed with and without their own spherical contact lenses. RESULTS: With this methodology, we evaluated the optical performance with RGP lenses compared with the natural optics. We estimated the contribution of the anterior surface of the contact lens, the internal ocular optics, flexure, and the tear lens aberrations to the optical performance of eyes wearing RGP contact lenses. We found that in three of four subjects, the contact lens significantly improved the natural optics of the eye. For the subject with higher dominance of corneal aberrations, root mean square (second-order and higher) decreased from 1.36 microm to 0.46 microm. Third- and higher-order aberrations decreased from 0.77 microm to 0.39 microm. The internal optics and lens flexure imposed limits on aberration compensation. Spherical RGP contact lenses did not produce spherical aberration potentially due to a compensatory role of the tear lens. CONCLUSIONS: Aberration measurements are useful to understand the fitting of contact lenses and the interaction with tear, cornea, and internal optics of the eye. Aberrometry can help to choose the best standard RGP lens parameters to improve the optics of individual eyes.

Aberrations of the human eye in visible and near infrared illumination.

PURPOSE: In most current aberrometers, near infrared light is used to measure ocular aberrations, whereas in some applications, optical aberration data in the visible range are required. We compared optical aberration measurements using infrared (787 nm) and visible light (543 nm) in a heterogeneous group of subjects to assess whether aberrations are similar in both wavelengths and to estimate experimentally the ocular chromatic focus shift. METHODS: Ocular aberrations were measured in near infrared and visible light using two different laboratory-developed systems: laser ray tracing (LRT) and Shack-Hartmann. Measurements were conducted on 36 eyes (25 and 11 eyes, respectively), within a wide range of ages (20 to 71 years), refractive errors (-6.00 to +16.50), and optical quality (root mean square wavefront error, excluding defocus, from 0.40 to 9.89 microm). In both systems, wave aberrations were computed from the ray aberrations by modal fitting to a Zernike polynomial base (up to seventh order in laser ray tracing and sixth order in Shack-Hartmann). We compared the Zernike coefficients and the root mean square wavefront error corresponding to different terms between infrared and green illumination. RESULTS: A Student's t-test performed on the Zernike coefficients indicates that defocus was significantly different in all of the subjects but one. Average focus shift found between 787 nm and 543 nm was 0.72 D. A very small percentage of the remaining coefficients was found to be significantly different: 4.7% of the 825 coefficients (25 eyes with 33 terms) for laser ray tracing and 18.2% of the 275 coefficients (11 eyes with 25 terms) for Shack-Hartmann. Astigmatism was statistically different in 8.3% of the eyes, root mean square wavefront error for third-order aberrations in 16.6%, and spherical aberration (Z4(0)) in 11.1%. CONCLUSIONS: Aerial images captured using infrared and green light showed noticeable differences. Apart from defocus, this did not affect centroid computations because within the variability of the techniques, estimates of aberrations with infrared were equivalent to those measured with green. In normal eyes, the Longitudinal Chromatic Aberration of the Indiana Chromatic Eye Model can predict the defocus term changes measured experimentally, although the intersubject variability could not be neglected. The largest deviations from the prediction were found on an aphakic eye and on the oldest subject.