Search results for "Visual acuity"
showing 10 items of 456 documents
Visual performance with multifocal intraocular lenses
2004
Abstract Objective To evaluate distance and near visual performance under bright (photopic) and dim (mesopic) conditions in patients who had undergone uncomplicated cataract extraction with multifocal or monofocal intraocular lens (IOL) implantation. Design Prospective, nonrandomized, masked, comparative, observational case series. Participants Thirty-two eyes of 32 patients after zonal-progressive multifocal IOL implantation (Allergan Medical Optics Array SA-40N) and 32 eyes of 32 age-matched patients after monofocal IOL implantation (Allergan Medical Optics SI-40NB). Intervention All eyes underwent phacoemulsification and IOL implantation. Main outcome measures At 18 months after surgery,…
Effect of specialized applications on the visual functions of amblyopic eye in Latvian children
2021
The classical treatment option of amblyopia is occlusions of non-amblyopic eye. The newest methods involve specialized computer and phone games, applications that involve both eyes in visual processing during treatment as well as stimulate binocularity. The aim of the work was to assess the efficiency of specialized phone application ‘Duovision’ in the treatment of amblyopia in preschool-age children. There were 30 participants (5-8 years old): 16 participants had occlusion therapy; 14 participants played the specialized phone application Duovision®. The visual acuity of amblyopic eye, as well as stereopsis was evaluated at near and far distances before the treatment, 2 and 4 months after t…
Effect of Light Scattering Simulation in the Eye on Different Color Stimuli Perception
2008
One of the factors which influences visual functions is intraocular light scattering. To assess the effect of light scattering and stimulus color on visual functions, visual acuity and retinal straylight were measured with and without light scattering occluder. For visual acuity measurements black Landolt optotypes on red, green and blue background were used. Retinal straylight was measured with a direct compensation method using the same colors stimuli. For one subject straylight was measured with 5 different light scattering levels of eye occluder.
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…
Looking in Depth: Visual Distance Perception of Stimuli on Volumetric Multi-Planar Display
2018
Ability to distinguish relative location of visual stimuli on a multi-planar display was evaluated within psychophysical experiment in order to figure out the impact of physical distance between stimuli across depth of volumetric data.
Colour vision experimental studies in teaching of optometry
2005
Following aspects related to human colour vision are included in experimental lessons for optometry students of University of Latvia. Characteristics of coloured stimuli (emitting and reflective), determination their coordinates in different colour spaces. Objective characteristics of transmitting of colour stimuli through the optical system of eye together with various types of appliances (lenses, prisms, Fresnel prisms). Psychophysical determination of mono- and polychromatic stimuli perception taking into account physiology of eye, retinal colour photoreceptor topography and spectral sensitivity, spatial and temporal characteristics of retinal receptive fields. Ergonomics of visual perce…
Visual Search Performance Depending on Target-Distractor Difference on Volumetric Display and Flat Panel Display
2019
The search items were demonstrated on the volumetric display and flat panel display. In contrast to the correct response rate, the search time and number of interactions were considerably affected by the type of visualization.
Digitālās refrakcijas pielietojums labākā koriģētā redzes asuma novērtēšanai
2021
Darbs ir uzrakstīts angļu valodā uz 36 lappusēm, satur 20 attēlus, 4 tabulas un 35 literatūras avotus. Darba mērķis ir pārbaudīt redzes asumu ar trim refrakcijas metodēm: autorefraktometriju, subjektīvo refraktometriju un digitālo refraktometriju ar ierīci ESSILOR Vision R-800. Tika salīdzināta refrakcija 15 subjektiem vecumā no 12 līdz 40 gadiem. Refrakcijas dati tika pārveidoti optiskā stipruma vektora formā. Rezultāti: Statistiski nozīmīgas atšķirības tika konstatētas redzes asumam, bet ne optiskā stipruma vektoriem, kas bija ļoti līdzīgi viens otram. Secinājums: digitālā refrakcija ar precizitāti 0,01 D pie nepārtrauktas optiskā stipruma maiņas parādīja labāku redzes asumu pat pie zema …
Cataract surgery in West Africa: is couching still a choice?
2012
Eye Cataract Simulation Using Polymer Dispersed Liquid Crystal Scattering Obstacles
2004
Polymer dispersed liquid crystals with electrically induced variations of light scattering extent similar to that of transparent PLZT ceramics are used for simulation of different development stages of eye cataract. Wavelength dependencies of scattering are determined in the visible spectral range, and human visual response looking through the scattering obstacle to the onset of various spatial frequency stimuli is determined psychophysically and electrophysiologically in order to find correlation between the scattering extent, visual acuity and visual evoked potential VEP chromatic characteristics.