Search results for "Cornea"
showing 10 items of 404 documents
Objective and subjective evaluation of photic phenomena after monofocal and multifocal intraocular lens implantation11The authors have no commercial …
1999
Abstract Objective To objectively measure and compare halo, flicker, and glare disability in pseudophakic eyes with monofocal (MONO) and multifocal (MULTI) intraocular lenses (IOLs) with respect to the influence of corneal surface quality, astigmatism, and age. Design Prospective case series. Participants This clinical trial involved 28 eyes of 28 patients after small-incision cataract surgery with a MONO silicone IOL and 28 eyes of 28 patients with zonal-progressive silicone IOL. Intervention A computer program objectively determined halo, glare, and flicker. Corneal surface quality and astigmatism were measured using computerized videokeratography. Ray-tracing analysis was performed based…
Successful Topical Application of Caspofungin in the Treatment of Fungal Keratitis Refractory to Voriconazole
2010
Fungal keratitis is an important ophthalmic problem because it leads to corneal blindness and sometimes to loss of the eye.1,2 There is no agreed protocol for the treatment of suspected fungal keratitis. Topical and oral voriconazole have now been reported to be effective.3 However, some cases do not respond to this treatment. New antifungal agents such as caspofungin acetate, 0.5%, are promising alternatives
In vitro optical performance of a new aberration-free intraocular lens
2014
To assess the optical performance of the new EnVista intraocular lens (IOL). Four aspheric IOLs were evaluated; the new EnVista is one amoung them. This IOL, similarly to the Z-Flex HB and the Bi-Flex 1.8 667AB ones, has a neutral aspheric design, whereas the fourth IOL under test (AcrySof IQ IOL SN60WF) presents a negative spherical aberration (SA). The IOL’s aberration patterns were measured in vitro, by setting them up on an optical bench. From these aberration-pattern data, the modulation transfer function (MTF), the average modulation values, and the points spread function (PSF) were calculated. Furthermore, in order to assess the potential optical quality that these IOLs would yield o…
The tear film and the optical quality of the eye
2010
The stability of the tear film plays an important role in the optical quality of the eye. Various methods have been developed to quantify the contribution of the tear film to optical quality, including the double-pass optical method, Hartmann-Shack wavefront sensing, videokeratoscopy, retroillumination analysis, and interferometry. In addition to assessing the effect of tear film irregularities, these methods can aid in the diagnosis of dry-eye related conditions and the monitoring of therapy. This review describes the methodologies used to assess the relationship between the tear film and optical quality of the eye and summarizes the most important findings obtained with these methods with…
Time Course of Inflammation and Apoptosis in a Scopolamine–Induced Dry Eye Rat Model
2006
International audience; Purpose: : Dry eye syndrome is due to tear secretion deficiency or excessive tear evaporation leading to tear film instability. The aim of this study was to evaluate the time course of inflammation and apoptosis in a scopolamine–induced dry eye rat model. Methods: : Osmotic pumps continuously delivering scopolamine (12.5mg/d) were implanted subcutaneously in female Lewis rats for 1, 2, 3, 7, 10, 17 and 28 days. During the treatment, the corneal status was assessed by fluorescein impregnation and tears were collected for prostaglandin E2 (PGE2) immunoassay. At the end of the treatment period, the animals were sacrificed and the ocular tissues and the lacrimal glands w…
Depth-of-Field of the Accommodating Eye
2014
Our eyes project information from a three-dimensional world to a basically two-dimensional surface, corresponding to the photoreceptor plane in the retina. In theory, only one plane or surface of world can be in focus at one time. However, the eye exhibits a certain tolerance to out-of-focus images, a feature that is known as depth-of-focus (DOF). The corresponding distance range in which the objects are seen “clearly” is known as depth-of-field (DOFi). Although DOF and DOFi refer to an interval of distances or a dioptric range in the image and object space, respectively, both parameters define a similar concept and are usually interchangeable. This article will mainly refer to DOFi because…
Evaluation of the iridocorneal angle with accommodation using optical coherence tomography
2017
The changes in the iridocorneal angle structure during accommodation are assessed by means of anterior segment optical coherence tomography. Thirteen right eyes were included in the study. The device used for the measurement was the Visante® omni system. The stimuli were set up at different vergences (0.0 D, -1.5 D, and -3.0 D). The angle opening distance 500 and 750, the trabecular iris space area 500 and 750, and the scleral spur angle parameters were assessed at the nasal and temporal regions. The results in the iridotrabecular angle comparing the three accommodative states of the eye did not yield any statistically significant difference at nasal or temporal angle sections. In light of …
Ortokeratoloģijas lēcas dizaina ietekme uz acs aksiālā garuma izmaiņām.
2020
Maģistra darbs ir uzrakstīts angļu valodā uz 59 lapaspusēm. Tas satur 24 attēlus, 3 tabulas un 85 literatūras atsauces. Pētījuma mērķis bija novērtēt miopijas kontroles ortokeratoloģijas lēcu formas un optiskās zonas platuma ietekmi uz miopijas progresijas mazināšanu. Darbā tika analizēti 12 bērnu ar augstu miopijas pakāpi ortokeratoloģijas rezultāti, iegūti kopā no 19 acīm. Tika salīdzinātas acs aksiālā garuma izmaiņas, bērniem nēsājot parastas ortokeratoloģijas lēcas un lietojot specializētās miopijas kontroles ortokeratoloģijas lēcas. Rezultāti parādīja, ka specializētās ortokerotoloģijas lēcas daudz efektīvāk samazina acs aksiālā garuma palielināšanos nekā parastās lēcas. Atslēgas vārdi…
Adaptación visual a la distorsión luminosa y agudeza de bajo contraste en pacientes bajo terapia corneal refractiva.
2015
Antecedentes: La Ortoqueratología (OK) o terapia refractiva corneal (CRT) es un tratamiento para corregir el error refractivo mediante el moldeo la cara anterior de la córnea con la aplicación programada de unas lentes de contacto rígidas permeables al gas (RGP) diseñadas especialmente (LC). La técnica es efectiva y la FDA la aprobó para un error refractivo de -6,00D de esfera y -1,50D de cilindro. Algunos profesionales afirman que se pueden conseguir correcciones para valores superiores de miopía y astigmatismo, hipermetropía y presbicia, pero estas aplicaciones están en este trabajo fuera de contexto. A pesar de su eficacia, la técnica tiene algunas desventajas intrínsecas a la remodelaci…
Quantitative descriptors in myopic eyes
2020
La prevalencia de la miopía ha demostrado ser mayor entre la población con una educación superior. Se cree que el tiempo dedicado a actividades de trabajo cercano tiene un papel en dicha asociación entre la miopía y el nivel educativo alcanzado. De hecho, el tiempo dedicado al trabajo cercano y su intensidad, especialmente la lectura continua, han demostrado aumentar las probabilidades de miopía en niños. Los estudiantes universitarios constituyen un grupo de población joven expuesto a mucho trabajo cercano prolongado por lo que que tiene un riesgo especial de desarrollo y progresión de la miopía durante sus estudios. Esta investigación tuvo como objetivo caracterizar el ojo miope mediante …