The Covid-19 outbreak in Spain. A simple dynamics model, some lessons, and a theoretical framework for control response.

Spain is among the countries worst hit by the Covid-19 pandemic, with one of the highest rate of infections and deaths per million inhabitants. First positive was reported on late January 2020. Mid March, with 7,000 confirmed cases, nationwide lockdown was imposed.

Leprosy in the twenty-first century: a microbiological, clinical, and epidemiological study in northwestern Spain.

Leprosy, or Hansen's disease, is a chronic granulomatous disease caused by Mycobacterium leprae and the recently discovered Mycobacterium lepromatosis. In Spain and other countries, where leprosy has been eliminated, an increasing number of imported cases have been documented, especially from South Africa and South America. The diagnosis of leprosy is mainly clinical, based on the signs established by the World Health Organization (WHO), although laboratory tools can be useful for diagnostic confirmation.

Agreement between refractive and corneal astigmatism in pseudophakic eyes.

Purpose: To examine the agreement and relationship between refractive and corneal astigmatism in a population of pseudophakic eyes.

Methods: Patients of age at least 40 years, visual acuity 20/40 or better, and no ocular disease were included (n = 111). Refractive astigmatism was obtained by subjective refraction.

Image metrics for predicting subjective image quality.

Purpose: Despite the proliferation of wavefront sensors to characterize the optical quality of individual eyes, there is not yet an accurate way to determine from a wave aberration how severely it will impact the patient's vision. Some of the most commonly used metrics, such as RMS wavefront error and the Strehl ratio, predict subjective image quality poorly. Our goal is to establish a better metric to predict subjective image quality from the wave aberration.

Theoretical elastic response of the cornea to refractive surgery: risk factors for keratectasia.

Purpose: To explore the role that mechanical elastic factors may have in post-refractive surgery corneal phenomena, from mild curvature changes to keratectasia.

Methods: The central cornea near the apex was modeled as an elastic spherical thin shell loaded by the intraocular pressure (IOP). Equations for myopic laser in situ keratomileusis (LASIK) were obtained to estimate shifts and curvature changes of the posterior corneal surface at the apex.

Corneal aberrations before and after small-incision cataract surgery.

Purpose: To study the effect of small-incision cataract surgery on the optical aberrations of the cornea.

Methods: Corneal topography was measured before and after cataract surgery on 70 eyes of 70 patients. Monofocal foldable IOLs were implanted after phacoemulsification through a clear-cornea, 3.

Effect of beam size on the expected benefit of customized laser refractive surgery.

Purpose: Customized laser surgery attempts to correct higher order aberrations, as well as defocus and astigmatism. The success of such a procedure depends on using a laser beam that is small enough to produce fine ablation profiles needed to correct higher order aberrations.

Methods: Wave aberrations were obtained from a population of 109 normal eyes and 4 keratoconic eyes using a Shack-Hartmann wavefront sensor.

A method to predict refractive errors from wave aberration data.

We explored the impact of the eye's higher-order aberrations on subjective refraction comparing two classes of methods for estimating refractive state, one based directly on the wave aberration defined in the pupil plane and another based on the retinal image plane. The method defined in the pupil plane chose the sphere and cylinder that either minimized the wave aberration root mean square or minimized the sum of all the spherical and cylindrical components in the wave aberration. The method defined in the image plane chose the sphere and cylinder that optimized an image-quality metric such as the Strehl intensity ratio, the entropy and the intensity variance of the point-spread function, the volume under the modulation transfer function, or the volume under the contrast-sensitivity function.

Peripheral refractive errors in myopic, emmetropic, and hyperopic young subjects.

To gain more insight into the relationship between foveal and peripheral refractive errors in humans, spheres, cylinders, and their axes were binocularly measured across the visual field in myopic, emmetropic, and hyperopic groups of young subjects. Both automated infrared photorefraction (the "PowerRefractor"; www. plusoptix.

Corneal optical aberrations and retinal image quality in patients in whom monofocal intraocular lenses were implanted.

Objectives: To compare retinal image quality and optical corneal aberrations in patients in whom monofocal polymethyl methacrylate intraocular lenses (IOLs) were implanted with those in healthy subjects of a similar older age (60-70 years old) and to use the results to suggest improved optical designs of IOLs to maximize retinal image quality.

Methods: A double-pass apparatus was used to measure retinal image quality for 3-, 4-, and 6-mm pupil diameters. Corneal aberrations for a 4-mm pupil were calculated by a ray-tracing technique from the elevations provided by corneal topography.

Calculated impact of higher-order monochromatic aberrations on retinal image quality in a population of human eyes.

We calculated the impact of higher-order aberrations on retinal image quality and the magnitude of the visual benefit expected from their correction in a large population of human eyes. Wave aberrations for both eyes of 109 normal subjects and 4 keratoconic patients were measured for 3-, 4-, and 5.7-mm pupils with a Shack-Hartmann sensor.

Contribution of the cornea and internal surfaces to the change of ocular aberrations with age.

We studied the age dependence of the relative contributions of the aberrations of the cornea and the internal ocular surfaces to the total aberrations of the eye. We measured the wave-front aberration of the eye with a Hartmann-Shack sensor and the aberrations of the anterior corneal surface from the elevation data provided by a corneal topography system. The aberrations of the internal surfaces were obtained by direct subtraction of the ocular and corneal wave-front data.

Method for optimizing the correction of the eye's higher-order aberrations in the presence of decentrations.

The use of a correcting element to compensate for higher-order aberrations in an optical system often requires accurate alignment of the correcting element. This is not always possible, as in the case of a contact lens on the eye. We propose a method consisting of partial correction of every aberration term to minimize the average variance of the residual wave-front aberration produced by Gaussian decentrations (translations and rotations).

Calculated impact of higher-order monochromatic aberrations on retinal image quality in a population of human eyes.

We calculated the impact of higher-order aberrations on retinal image quality and the magnitude of the visual benefit expected from their correction in a large population of human eyes. Wave aberrations for both eyes of 109 normal subjects and 4 keratoconic patients were measured for 3-, 4-, and 5.7-mm pupils with a Shack-Hartmann sensor.