Search results for "Lentes de contacto"
showing 10 items of 12 documents
Lentes de contacto multifocales basadas en la visión simultánea para corrección de la presbicia
2013
En la actualidad, en España, hay 46.704.314 habitantes (INE, 2013) de los cuales un 49,79% aproximadamente son présbitas. Esta población de pacientes representa el segmento de crecimiento más grande. Aproximadamente en una plazo entre 5 y 7 años aparecerán más de 11 millones de nuevos présbitas (INE, 2013).La población présbita es un segmento relativamente inexplorado en lo que se refiere al mercado de la lente de contacto (LC), siendo una buena oportunidad para los fabricantes y laboratorio. Las adaptaciones de lente de contacto multifocal (LCM) y monovision representan sólo un 9% de las adaptaciones a nivel mundial, por ello es predecible que el mercado de la LC en este tipo de adaptacion…
Visual simulation of different optical designs
2016
La presbicia es la pérdida irreversible de la capacidad de acomodar del ojo humano asociada a la edad, que afecta al rendimiento visual para con objetos cercanos. La presente Tesis Doctoral tiene como objetivo evaluar los aspectos ópticos y visuales de diferentes diseños multifocales para el tratamiento de la presbicia que se encuentran en lentes de contacto e intraoculares. En primer lugar, se implementó una métrica que facilita la evaluación in vitro de las lentes intraoculares. La idea de esta métrica se basa en la función de transferencia de modulación axial de las lentes intraoculares, la cual puede obtenerse con un instrumento de laboratorio adecuado. La métrica evalúa el volumen bajo…
Rendimiento visual con lentes de contacto multifocales tóricas de visión simultánea
2012
Análisis del rendimiento visual con lentes de contacto multifocales tóricas de visión simultánea. Para ello se evaluaron los parámetros de agudeza visual, curvas de desenfoque, agudeza visual estereoscópica,medidas de las pupilas en distintas condiciones de iluminación, función de sensibilidad al contraste así como un cuestionario normalizado de satisfacción.
Corrigendum to “Short-term changes in light distortion in orthokeratology subjects"
2015
Artigo completo publicado na revista "BioMed Research International, (2015), 1-7" e disponível no RepositóriUM em: http://hdl.handle.net/1822/33375
Lentes de contacto rígidas permeables al gas corneo-esclerales de alto Dk en la rehabilitación visual de pacientes con queratocono
2017
INTRODUCCIÓN Las ectasias corneales son distrofias progresivas que afectan a la morfología corneal, provocando alteraciones funcionales debido a que inducen una forma cónica irregular, disminuyendo la visión de los pacientes. El queratocono es una ectasia corneal que provoca aberraciones de alto orden que empeoran la calidad de visión, especialmente en los casos donde la enfermedad está más desarrollada. De entre todos los tratamientos actuales, la cirugía con implante de anillos intracorneales intenta eliminar la deformidad de la córnea para mejorar la agudeza visual. Los resultados visuales tras la cirugía en unos casos son satisfactorios, en cambio, en otros, los pacientes no quedan sati…
Objective assessment of the effect of pupil size upon the power distribution of multifocal contact lenses
2017
AIM: To analytically assess the effect of pupil size upon the refractive power distributions of different designs of multifocal contact lenses. METHODS: Two multifocal contact lenses of center-near design and one multifocal contact lens of center-distance design were used in this study. Their power profiles were measured using the NIMO TR1504 device (LAMBDA-X, Belgium). Based on their power profiles, the power distribution was assessed as a function of pupil size. For the high addition lenses, the resulting refractive power as a function of viewing distance (far, intermediate, and near) and pupil size was also analyzed. RESULTS: The power distribution of the lenses was affected by pupil siz…
Nonsurgical Procedures for Keratoconus Management
2017
Objectives. To describe the past 20 years’ correction modalities for keratoconus and their visual outcomes and possible complications.Methods. A review of the published literature related to the visual outcomes and possible complications in the context of keratoconus management using nonsurgical procedures for the last 20 years (glasses and contact lenses) was performed. Original articles that reported the outcome of any correction modalities of keratoconus management were reviewed.Results. The most nonsurgical procedure used on keratoconus management is the contact lens fitting. Soft contact lenses and soft toric contact lenses, rigid gas-permeable contact lenses, piggyback contact lens sy…
Impact of contact lens material and design on the ocular surface.
2018
BACKGROUND: To evaluate the impact on the ocular surface of a daily disposable hydrogel contact lens with high water content compared with two silicone hydrogel daily disposable lenses of lower water content. METHODS: The hydrogel lens assessed was made from nesofilcon A and the silicone hydrogel lenses were made of delefilcon A and stenfilcon A. Contact lens thickness was measured to assess material stability during daily wear, and ocular surface parameters such as tear film osmolarity, tear meniscus area and central corneal thickness were also assessed. Optical quality was analysed for all cases by means of wavefront aberrometry. RESULTS: The nesofilcon A was shown to be the thinnest lens…
Stereoacuity with simultaneous vision multifocal contact lenses.
2010
Our purpose was to evaluate near stereoacuity (SA) with Focus Progressives and PureVision Multifocal simultaneous vision contact lenses. In a cross-over study design, 20 presbyopic subjects were fitted with either the Focus Progressives or PureVision Multifocal lenses. After 1 month, SA was measured with the vectographic Titmus, Random dot stereotests, and the Howard-Dolman apparatus under photopic conditions (85 lux) at 40 cm. Binocular high-contrast visual acuity at distance and near was examined. Subjects were then refitted with the alternative correction and the procedure was repeated. Mean SA with the Focus Progressive was 21 +/- 7 sec arc, 54 +/- 17 sec arc, and 51 +/- 21 sec arc, wit…
Short-Term Changes in Light Distortion in Orthokeratology Subjects
2015
Purpose. Quantifying adaptation to light distortion of subjects undergoing orthokeratology (OK) for myopia during the first month of treatment. Methods. Twenty-nine healthy volunteers (age: 22.34 ± 8.08 years) with mean spherical equivalent refractive error −2.10 ± 0.93D were evaluated at baseline and days 1, 7, 15, and 30 of OK treatment. Light distortion was determined using an experimental prototype. Corneal aberrations were derived from corneal topography for different pupil sizes. Contrast sensitivity function (CSF) was analyzed for frequencies of 1.50, 2.12, 3.00, 4.24, 6.00, 8.49, 12.00, 16.97, and 24.00 cpd under photopic conditions. Results. Average monocular values of all light di…