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Carolina Ortiz, José J Esteve-Taboada, Lurdes Belda-Salmerón, Daniel Monsálvez-Romín, Alberto Domínguez-Vicent
PURPOSE: To analyze the effect of decentration on the optical quality of two diffractive-refractive intraocular lenses, a bifocal and a trifocal, when displaced laterally (horizontal direction) from the center. METHODS: The AT LISA 809M IOL (+3.75 D add) with two main foci and the AT LISA tri 839MP intraocular lens with three main foci (Carl Zeiss Meditec AG, Jena, Germany) were analyzed. The optical quality of the intraocular lenses was measured with the PMTF (power and modulation transfer function [MTF] measurement for refractive and diffractive intraocular lenses) optical bench (Lambda-X, Nivelles, Belgium)...
October 22, 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Chunming Liu, Stefanie A Drew, Eric Borsting, Amy Escobar, Lawrence Stark, Christopher Chase
The purpose of this study is to examine the potential relationship between tonic accommodation (TA), near work induced TA-adaptation and the steady state closed-loop accommodation response (AR). Forty-two graduate students participated in the study. Various aspects of their accommodation system were objectively measured using an open-field infrared auto-refractor (Grand Seiko WAM-5500). Tonic accommodation was assessed in a completely dark environment. The association between TA and closed-loop AR was assessed using linear regression correlations and t-test comparisons...
October 17, 2016: Vision Research
Nicholas Hoai Nam Nguyen
PURPOSE: To evaluate the performance of a holographic logMAR chart for the subjective spherical refraction of the human eye. METHODS: Bland-Altman analysis was used to assess the level of agreement between subjective spherical refraction using the holographic logMAR chart and conventional autorefraction and subjective spherical refraction. RESULTS: The 95% limits of agreement (LoA) were calculated between holographic refraction and the two standard methods (subjective and autorefraction)...
October 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Thomas Politzer, Amy Berryman, Karen Rasavage, Lawrence Snell, Allan Weintraub, Donald J Gerber
BACKGROUND: Oculomotor deficits in smooth pursuit, saccades, vestibular-ocular reflex (VOR), vergence, and fixation are common problems seen after moderate to severe traumatic brain injury (TBI). No scale currently exists to rate all of these together. The Craig Hospital Eye Evaluation Rating Scale (CHEERS) was designed to systematically quantify frequency and severity of eye movement deficits in TBI. OBJECTIVE: To assess the intra- and interrater reliability of a new rating scale for detecting the presence and degree of 5 oculomotor abnormalities after TBI...
September 21, 2016: PM & R: the Journal of Injury, Function, and Rehabilitation
David A Gonzalez, Ewa Niechwiej-Szwedo
The contribution of binocular vision to the performance of reaching and grasping movements has been examined previously using single reach-to-grasp movements. However, most of our daily activities consist of more complex action sequences, which require precise temporal linking between the gaze behaviour and manual action phases. Many previous studies found a stereotypical hand-eye coordination pattern, such that the eyes move prior to the reach initiation. Moving the eyes to the target object provides information about its features and location, which can facilitate the predictive control of reaching and grasping...
September 26, 2016: Vision Research
Shin C Beh, Teresa C Frohman, Elliot M Frohman
BACKGROUND: The cerebellum plays a central role in the online, real-time control, and long-term modulation of eye movements. EVIDENCE ACQUISITION: We reviewed the latest (fifth) edition of Leigh and Zee's textbook, The Neurology of Eye Movements, and literature in PUBMED using the following terms: cerebellum, flocculus, paraflocculus, vermis, oculomotor vermis, dorsal vermis, caudal fastigial nucleus, fastigial oculomotor region, uvula, nodulus, ansiform lobule, eye movements, saccades, ipsipulsion, contrapulsion, smooth pursuit, vergence, convergence, divergence, gaze-holding, down beat nystagmus, vestibulo-ocular reflex (VOR), angular VOR, translational VOR, skew deviation, velocity storage...
September 16, 2016: Journal of Neuro-ophthalmology: the Official Journal of the North American Neuro-Ophthalmology Society
(no author information available yet)
PURPOSE: To compare the effectiveness of home-based (HB) computer vergence/accommodative therapy (HB-C) to HB near target push-up therapy (HB-PU) and to HB placebo treatment (HB-P) among children aged 9 to <18 years with symptomatic convergence insufficiency (CI). METHODS: In this multicenter randomized clinical trial, participants were randomly assigned to computer therapy, near target push-ups, or placebo. All therapy was prescribed for 5 days per week at home...
August 30, 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Kyeong Hwan Kim, Wan Soo Kim
PURPOSE: To evaluate visual outcome and patient satisfaction following implantation of multifocal intraocular lenses (IOLs) with a +1.5 diopters (D) addition compared with monofocal IOLs. METHODS: This prospective, nonrandomized, comparative case series involved 48 eyes (24 patients) who underwent cataract surgery with implantation of low-power-added multifocal IOLs (LS313-MF15; multifocal group) and 48 eyes (24 patients) with conventional monofocal IOLs (CTS204; monofocal group)...
August 24, 2016: Eye & Contact Lens
Pascaline Neveu, Corinne Roumes, Matthieu Philippe, Philippe Fuchs, Anne-Emmanuelle Priot
PURPOSE: Stereoscopic displays challenge the neural cross-coupling between accommodation and vergence by inducing a constant accommodative demand and a varying vergence demand. Stereoscopic viewing calls for a decrease in the gain of vergence accommodation, which is the accommodation caused by vergence, quantified by using the convergence-accommodation to convergence (CA/C) ratio. However, its adaptability is still a subject of debate. METHODS: Cross-coupling (CA/C and AC/A ratios) and tonic components of vergence and accommodation were assessed in 12 participants (27...
August 1, 2016: Investigative Ophthalmology & Visual Science
B M Sheliga, C Quaia, E J FitzGibbon, B G Cumming
We studied human short-latency vergence eye movements to a novel stimulus that produces interocular velocity differences without a changing disparity signal. Sinusoidal luminance gratings moved in opposite directions (left vs. right; up vs. down) in the two eyes. The grating seen by each eye underwent ¼-wavelength shifts with each image update. This arrangement eliminated changing disparity cues, since the phase difference between the eyes alternated between 0° and 180°. We nevertheless observed robust short-latency vergence responses (VRs), whose sign was consistent with the interocular velocity differences (IOVDs), indicating that the IOVD cue in isolation can evoke short-latency VRs...
August 1, 2016: Journal of Vision
Yifei Wu, Vidhyapriya Sreenivasan, Erin E Babinsky, T Rowan Candy
Young children experience decreased convergence and increased accommodation demands relative to adults, as a result of their small interpupillary distance and hyperopic refraction. Those with typical amounts of hyperopic refractive error must accommodate more than an emmetrope to achieve focused retinal images, which may also drive additional convergence through the neural coupling. Adults and older children have demonstrated vergence adaptation to a variety of visual stimuli. Can vergence adaptation help younger children achieve alignment in the presence of these potentially conflicting demands? Purkinje image eye tracking and eccentric photorefraction were used to record simultaneous vergence and accommodation responses in adults and young children (3-6 years)...
August 1, 2016: Journal of Vision
J Antonio Aznar-Casanova, August Romeo, Aurora Torrents Gómez, Pedro Martin Enrile
PURPOSE: When observers focus their stereoscopic visual system for a long time (e.g., watching a 3D movie) they may experience visual discomfort or asthenopia. We tested two types of models for predicting visual fatigue in a task in which subjects were instructed to discriminate between 3D characters. One model was based on viewing distance (focal distance, vergence distance) and another in visual direction (oculomotor imbalance). METHOD: A 3D test was designed to assess binocular visual fatigue while looking at 3D stimuli located in different visual directions and viewed from two distances from the screen...
August 17, 2016: Journal of Optometry
Guido Maiello, William J Harrison, Peter J Bex
Most eye movements in the real-world redirect the foveae to objects at a new depth and thus require the co-ordination of monocular saccade amplitudes and binocular vergence eye movements. Additionally to maintain the accuracy of these oculomotor control processes across the lifespan, ongoing calibration is required to compensate for errors in foveal landing positions. Such oculomotor plasticity has generally been studied under conditions in which both eyes receive a common error signal, which cannot resolve the long-standing debate regarding whether both eyes are innervated by a common cortical signal or by a separate signal for each eye...
2016: Scientific Reports
Michael Gallaway, Mitchell Scheiman, G Lynn Mitchell
PURPOSE: To determine the frequency and types of vision disorders associated with concussion, and to determine the success rate of vision therapy for these conditions in two private practice settings. METHODS: All records over an 18-month period of patients referred for post-concussion vision problems were reviewed from two private practices. Diagnoses of vergence, accommodative, or eye movement disorders were based on pre-established, clinical criteria. Vision therapy was recommended based on clinical findings and symptoms...
August 8, 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Mitchell M Scheiman, Henry Talasan, Gladys Lynn Mitchell, Tara L Alvarez
PURPOSE: To evaluate changes in objective measures of disparity vergence after office-based vision therapy (OBVT) for concussion-related convergence insufficiency (CI) and determine the feasibility of using this objective assessment as an outcome measure in a clinical trial. METHODS: This was a prospective, observational trial. All participants were treated with weekly OBVT with home reinforcement. Participants included two adolescents and three young adults with concussion-related, symptomatic CI...
July 23, 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Joseph Samuel Conrad, G Lynn Mitchell, Marjean Taylor Kulp
PURPOSE: To prospectively evaluate the effectiveness of home-based computer vergence therapy for the treatment of binocular vision disorders in adults at least 3 months after an acquired brain injury. METHODS: Eligibility criteria included presence of binocular dysfunction characterized by receded near point of convergence (≥6 cm break), insufficient positive fusional vergence at near (failing Sheard's criterion or <15△ blur or break), insufficient negative fusional vergence at near (<12△ blur or break), and/or reduced vergence facility at near (<15 cycles per minute with 12△BO/3△BI)...
July 23, 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Marco Ruggeri, Carolina de Freitas, Siobhan Williams, Victor M Hernandez, Florence Cabot, Nilufer Yesilirmak, Karam Alawa, Yu-Cherng Chang, Sonia H Yoo, Giovanni Gregori, Jean-Marie Parel, Fabrice Manns
Two SD-OCT systems and a dual channel accommodation target were combined and precisely synchronized to simultaneously image the anterior segment and the ciliary muscle during dynamic accommodation. The imaging system simultaneously generates two synchronized OCT image sequences of the anterior segment and ciliary muscle with an imaging speed of 13 frames per second. The system was used to acquire OCT image sequences of a non-presbyopic and a pre-presbyopic subject accommodating in response to step changes in vergence...
April 1, 2016: Biomedical Optics Express
Trent Koessler, Harold Hill
A hollow (concave) mask appears convex when viewed from beyond a certain distance even when viewed stereoscopically-this is the hollow-face illusion. At close viewing distances, the same mask is seen as hollow even when disparity information is eliminated by monocular viewing. A potential source of nonpictorial, monocular information that favors a veridical percept at close distances is accommodation in conjunction with focus blur. In this article, we used pinhole viewing to minimize this potential source of information and test whether it affects whether a hollow mask is seen as veridical (concave) or illusory (convex)...
August 2015: I-Perception
Paul V Johnson, Jared Aq Parnell, Joohwan Kim, Christopher D Saunter, Gordon D Love, Martin S Banks
Stereoscopic 3D (S3D) displays provide an additional sense of depth compared to non-stereoscopic displays by sending slightly different images to the two eyes. But conventional S3D displays do not reproduce all natural depth cues. In particular, focus cues are incorrect causing mismatches between accommodation and vergence: The eyes must accommodate to the display screen to create sharp retinal images even when binocular disparity drives the eyes to converge to other distances. This mismatch causes visual discomfort and reduces visual performance...
May 30, 2016: Optics Express
Agostino Gibaldi, Mauricio Vanegas, Peter J Bex, Guido Maiello
The Tobii Eyex Controller is a new low-cost binocular eye tracker marketed for integration in gaming and consumer applications. The manufacturers claim that the system was conceived for natural eye gaze interaction, does not require continuous recalibration, and allows moderate head movements. The Controller is provided with a SDK to foster the development of new eye tracking applications. We review the characteristics of the device for its possible use in scientific research. We develop and evaluate an open source Matlab Toolkit that can be employed to interface with the EyeX device for gaze recording in behavioral experiments...
July 11, 2016: Behavior Research Methods
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