Search results for "Optical transfer function"

showing 3 items of 53 documents

Effect of the color of the intraocular lens on optical and visual quality

2014

Purpose: To analyze the optical quality of intraocular lenses (IOL) with an orange (PC440Y) and a yellow (SN60AT) filter, and correlate these results with the visual quality of patients with these implants. Setting: Fisabio Oftalmología Médica, Valencia, Spain. Design: Randomized prospective study. Materials and Methods: The IOL optical quality was determined using the modulation transfer function (MTF) and the spectral transmission. The visual quality of 87 eyes with cataract (51 with orange filter and 36 with yellow filter) was determined by best corrected visual acuity (BCVA) and contrast sensitivity function (CSF) under photopic and mesopic conditions. To analyze the results, we use a S…

choroidal thicknessmedicine.medical_specialtyVisual acuityrecurrenceorangegenetic structuresvisual acuityMesopic visionmedicine.medical_treatmentcontrast sensitivity functionIntraocular lensOrange (colour)Cataractsurgerylcsh:OphthalmologyOptical transfer functionOphthalmologymedicinescanning laser polarimetryfilterbusiness.industryChoroidenhanced depth imagingBoth lensesretinal nerve fiber layereye diseasesyellowOphthalmologyglaucomaIntraocular lensesFixed corneal compensationlcsh:RE1-994OptometryExotropiaOriginal Articlesense organsmedicine.symptombusinessPhotopic visionIndian Journal of Ophthalmology
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Modulation transfer function in refractive-diffractive multifocal intraocular lenses in vitro

2007

Purpose: The optical quality of two types of multifocal, hybrid refractive-diffractive, intraocular lenses (IOL) is analyzed in vitro. Following the EN-ISO international standard, the IOLs’ modulation transfer functions (MTF) are determined for both distance and near vision. The behaviour of these curves when the pupil size varies is studied. Methods: The IOLs analyzed were: AcrySoft ResTor SN60D3 (Alcon) and Tecnis ZM900 (AMO). The MTF was calculated from the cross line-spread function recorded with the OPAL Vector System (Image Science Ltd. Oxford) by using fast Fourier transform techniques. The artificial eye model used simulates in vivo conditions of the anterior chamber including an ar…

genetic structuresbusiness.industryImage qualityStrehl ratioMultifocal intraocular lenseye diseasesPupilOptical qualityOphthalmologyOpticsIntraocular lensesOptical transfer functionMedicinesense organsImaging sciencebusinessActa Ophthalmologica Scandinavica
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Digital Acquisition and Processing of Video Angiocardiograms

1986

Angiocardiographic diagnosis is still mainly based on the visual assessment of radiographic projection images recorded on photographic film. Considerable amounts of contrast material have to be selectively injected into the circulation in order to make the regions of diagnostic relevance visible in the superposition of the shadows of tissue and bone structures displayed in these transmission images. In addition, selective angiocardiography requires exact positioning of the catheter, a time-consuming procedure which is not without risk. The processing of the angiographie films obtained is difficult to maintain at a constant high quality level, and this introduces an disadvantageous delay bet…

medicine.diagnostic_testbusiness.industryComputer scienceInterface (computing)media_common.quotation_subjectImage processingTransmission (telecommunications)Optical transfer functionDigital image processingmedicineContrast (vision)Computer visionAngiocardiographyArtificial intelligenceProjection (set theory)businessmedia_common
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