نتایج جستجو برای: fusional vergence amplitudes

تعداد نتایج: 30420  

2016
Godwin O. Ovenseri-Ogbomo Ovigwe Peter Eguegu

PURPOSE The study was designed to determine the prevalence of vergence dysfunctions among first year university students in Nigeria and to document the measures that define the vergence system of the visual system. METHODS A cross-sectional study of first year students of the University of Benin, Benin City, Nigeria, who presented for the mandatory eye examination as part of their medical exa...

Journal: :Archives of ophthalmology 2008

OBJECTIVE To compare home-based pencil push-ups (HBPP), home-based computer vergence/accommodative therapy and pencil push-ups (HBCVAT+), office-based vergence/accommodative therapy with home reinforcement (OBVAT), and office-based placebo therapy with home reinforcement (OBPT) as treatments for symptomatic convergence insufficiency. METHODS In a randomized clinical trial, 221 children aged 9...

2008
Yair Morad Horace Lee Carol Westall Stephen P Kraft Carole Panton Ruth Sapir-Pichhadze Moshe Eizenman

PURPOSE To evaluate whether a selected group of 9 children with history of congenital esotropia is capable of producing vergence eye responses to fusional disparity stimuli. METHODS Nine children with history of congenital esotropia and 5 age-matched children with normal binocular vision were examined. Using a full-field target, vergence responses to base out 3 prism diopters placed in front ...

2016
Jung Un Jang Inn-Jee Park Jung Yun Jang

BACKGROUND/PURPOSE To assess the distribution of near point of convergence (NPC), near heterophoria, and near vergence among myopic school children in South Korea. METHODS One hundred and thirty-six elementary school children, aged 8-13 years, were each given a thorough eye examination including binocular vision testing, NPC using standard push-up technique, horizontal heterophoria measuremen...

2012
Miriam L. Conway Jennifer Thomas Ahalya Subramanian

BACKGROUND The Mallett Unit is a clinical test designed to detect the fixation disparity that is most likely to occur in the presence of a decompensated heterophoria. It measures the associated phoria, which is the "aligning prism" needed to nullify the subjective disparity. The technique has gained widespread acceptance within professions such as optometry, for investigating suspected cases of...

2016
Samuel Otabor Wajuihian Rekha Hansraj

AIM To study the prevalence of nearpoint vergence anomalies (convergence insufficiency, convergence excess and fusional vergence dysfunction) and association with gender, age groups, grade level and study site (suburban and rural). METHODS The study design was cross sectional and data was analyzed for 1201 high school students aged 13-19 years who were randomly selected from 13 high schools i...

Journal: :Investigative ophthalmology & visual science 1979
J L Semmlow D Heerema

Two possible explanations are presented for the mechanism which limits the maximum fusional vergence response. An experimental paradigm is developed to differentiate between these alternatives. Experimental results indicate that the blur generally associated with strong fusional effort is due to convergence accommodation "overdrive." Th important theoretical and clinical implications of this fi...

Journal: :Vision Research 2014
Vidhyapriya Sreenivasan William R. Bobier

Convergence insufficiency (CI) is a developmental visual anomaly defined clinically by a reduced near point of convergence, a reduced capacity to view through base-out prisms (fusional convergence); coupled with asthenopic symptoms typically blur and diplopia. Experimental studies show reduced vergence parameters and tonic adaptation. Based upon current models of accommodation and vergence, we ...

Journal: :Investigative ophthalmology & visual science 1979
J L Semmlow G Hung

Traditional measurements of fixation disparity, like other binocular measurements, confound influences from both blur-driven and disparity-driven components. Measuring fixation disparity with accommodation open-loop eliminates accommodative interactions, and results show fixation disparity is reduced to about half the value observed normally for high levels of forced vergence. Thus fixation dis...

2005

Traditional measurements of fixation disparity, like other binocidar measurements, confound influences from both blur-driven and disparity-driven components. Measuring fixation disparity with accommodation open-loop eliminates accommodative interactions, and results show fixation disparity is reduced to about half the value observed normally for high levels of forced vergence. Thus fixation dis...

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