Search results for "Binocular vision"
showing 10 items of 24 documents
Binocular Vision in Patients with Multiple Sclerosis.
2021
Amparo Gil-Casas,1,2 David P Piñero-Llorens,2 Ainhoa Molina-Martin2 1Clínica Optométrica, Fundació Lluís Alcanyís, University of Valencia, Valencia, Spain; 2Optics and Visual Perception Group (GOPV), Department of Optics, Pharmacology, and Anatomy, University of Alicante, Alicante, SpainCorrespondence: Ainhoa Molina-MartinDepartment of Optics, Pharmacology, and Anatomy, University of Alicante, Carretera San Vicente del Raspeig, San Vicente del Raspeig, 03690, Alicante, SpainTel +34 965 903-400Email ainhoa.molina@ua.esPurpose: Oculomotor disorders have been reported in multiple sclerosis (MS) in up to 80% of cases. There have …
Visual performance comparison between contact lens-based pinhole and simultaneous vision contact lenses.
2011
Background The aim was to evaluate the visual performance provided with a contact lens-based pinhole design against a simultaneous vision multifocal contact lens. Methods In a cross-over study at the University of Valencia, 22 presbyopic patients were evaluated using an artificial pupil fitted on the non-dominant eye and the simultaneous vision PureVision Multifocal contact lenses. After one month of contact lens wear, binocular distance visual acuity (BDVA), binocular near visual acuity (BNVA), defocus curve, binocular distance contrast sensitivity, binocular near contrast sensitivity, and stereoacuity were measured, under photopic conditions (85 cd/m2). In addition, binocular distance vis…
Monocular versus binocular pupillometry.
2004
Purpose To quantify differences between monocular and binocular pupil size measurement under scotopic and mesopic conditions. Setting Department of Ophthalmology, Johannes Gutenberg-University, and Department of Medical Biometry, Epidemiology and Informatics, University of Mainz, Mainz, Germany. Methods Computerized dynamic pupillometry (P2000 SA, Procyon Instruments Ltd.) was used at 3 illumination levels: scotopic at 0.03 lux, mesopic low at 0.82 lux, and mesopic high at 6.4 lux. One hundred forty eyes of 70 healthy volunteers without ocular pathology were examined. The subjects were divided into 2 groups. In the first group, the pupil diameter was measured binocularly first. In the secon…
Changes in physiological astigmatism of human eye during accommodation in emmetropes (Conference Presentation)
2017
Introduction: Most young emmetrope eyes are far from ideal and have some degree of minor spherocylindrical error including also physiological astigmatism. Because of the changes in the shape of optical interfaces, pupil size, eyelid pressure, tear film, body posture, binocularity and accommodation astigmatism is considered as constantly dynamic phenomenon (Cheng et al, 2004). The purpose of this study was to evaluate and quantify changes in physiological astigmatism during accommodation. Method: Twenty young emmetropes with mean age 24 ± 4 years were selected for the study. Refraction and accommodative response were measured monocularly for dominant eye with an open-field infrared autorefract…
Vision evaluation in people with Down's syndrome.
1994
We tested the colour vision of 72 people with Down's syndrome using the Ishihara test and an anomaloscope. We found that 13 of the subjects, 6 males and 7 females, had defective colour vision according to Pickford's classification. In monocular vision 10 eyes were protan (five simple, three extreme and two deviant), one eye was simple deuteranomalous and the remaining eyes were normal: in binocular vision four of the subjects were protan (two simple and two deviant), two subjects were deutan (one simple and one deviant) and the rest were normal. Many of our subjects had lens opacities, strabismus, nystagmus, hypermetropia, high myopia and astigmatism, confirming literature reports. The cont…
Stereopsis assessment at multiple distances with an iPad application
2017
[EN] We present a new application for iPad for screening stereopsis at multiple distances that allows testing up to ten levels of stereoacuity at each distance. Our approach is based on a random dot stereogram viewable with anaglyph spectacles. Sixty-five subjects with no ocular diseases, wearing their habitual correction were measured at 3 m and 0.5 m. Results were compared with a standard stereoscopic test (TNO). We found not statistically significant differences between both tests, but our method achieved higher reproducibility. Applications in visual screening programs and to design and use of 3D displays, are suggested. (C) 2017 Elsevier B.V. All rights reserved.
Symptomatic accommodative and binocular dysfunctions from the use of flat-panel displays
2018
AIM: To determine the presence of symptomatic accommodative and non-strabismic binocular dysfunctions (ANSBD) in a non-presbyopic population of video display unit (VDU) users with flat-panel displays. METHODS: One hundred and one VDU users, aged between 20 to 34y, initially participated in the study. This study excluded contact-lens wearers and subjects who had undergone refractive surgery or had any systemic or ocular disease. First, subjects were asked about the type and nature of eye symptoms they experienced during VDU use. Then, a thorough eye examination excluded those subjects with a significant uncorrected refractive error or other problem, such as ocular motility disorders, vertica…
Developmental dyslexia: Visual abnormalities during ocular rotation
2005
[u]Purpose[/u]: Most of the studies dealing with visual perception disabilities in children suffering from developmental dyslexia have been done in orthophoric position. The objective of the present study is to explore the visual perception during eye movements. [u]Methods[/u]: Sixty male patients (11.8 ± 1.8 years) were examined by neuropsychologists to evaluate reading difficulties. Visual perception during ocular rotation was assessed with a Clement Clarke synoptophore with G3–G4 slides, in primary gaze, then laterally at 20, 30 and 40° in dim light. [u]Results[/u]: Three main abnormalities were found. • Isolated perception abnormalities with intermittent shading of the image, central, p…
Monocular Versus Binocular Calibrations in Evaluating Fixation Disparity With a Video-Based Eye-Tracker
2015
When measuring fixation disparity (an oculomotor vergence error), the question arises as to whether a monocular or binocular calibration is more precise and physiologically more appropriate. In monocular calibrations, a single eye fixates on a calibration target that is taken as having been projected onto the center of the fovea; the corresponding vergence state represents the heterophoria (the resting vergence position), which has no effect on the calibration procedure. In binocular calibrations, a vergence error may be present and may affect the subsequent measurement of the fixation disparity during binocular recordings. This study includes a test of the precision of both monocular and …
<p>Alteration in binocular fusion modifies audiovisual integration in children</p>
2019
Background: In the field of multisensory integration, vision is generally thought to dominate audiovisual interactions, at least in spatial tasks, but the role of binocular fusion in audiovisual integration has not yet been studied. Methods: Using the Maddox test, a classical ophthalmological test used to subjectively detect a latent unilateral eye deviation, we checked whether an alteration in binocular vision in young patients would be able to change audiovisual integration. The study was performed on a group of ten children (five males and five females aged 11.3±1.6 years) with normal binocular vision, and revealed a visual phenomenon consisting of stochastic disappearanceof part of a vi…