PURPOSE Reading a text requires vergence angle adjustments, so that the images in the two eyes fall on corresponding retinal areas. Vergence adjustments bring the two retinal images into Panum's fusional area and therefore, small remaining errors or regulations do not lead to double vision. The present study evaluated dynamic and static aspects of the binocular coordination when upcoming text w...

PURPOSE Currently, only a few reports have recommended surgery as a suitable treatment for blepharoptosis associated with myasthenia gravis. The present study aims to introduce our surgical criteria, surgical options, outcomes, and precautions for medically refractory myasthenic blepharoptosis. PATIENTS AND METHODS Eight patients who failed to respond to at least 2 years of medical treatment ...

PURPOSE Fixation disparity, i.e. the vergence error for stationary fusion stimuli, can be measured objectively with eye trackers and subjectively with nonius lines. Between these two measures, previous studies found differences that tended to be proportional to the amount of forced vergence, i.e. the discrepancy between vergence and accommodative stimulus. We investigate whether objective and s...

Clinical studies in non-specific chronic arthralgia and back pain seem to indicate an association between vertical heterophoria (VH - latent vertical retinal misalignment) and asymmetrical head rotation. Such clinical observations suggest a link between VH and head rotation, but this was never tested. The purpose of this study was to simulate a VH in healthy subjects and examine its influence o...

This study sought to determine the linearity and amplitude of both proximally induced accommodation (PIA) and vergence (PIV) by comparing the open-loop accommodation and vergence responses, respectively, to individual stimuli located at viewing distances ranging from 0.20 m to 1,500 m. For the measurement of PIA, the vergence and accommodation loops were opened by subjects (N = 10) monocularly ...

OBJECTIVE To assess asthenopia prevalence and associated factors in schoolchildren aged 6-16. METHODS This was a cross-sectional study of all children attending the first to eighth grades at two public schools in the urban region of a medium-sized town in Southern Brazil between April and December 2012. A questionnaire on socioeconomic and cultural matters was answered by parents, while the c...

PURPOSE This clinical study was performed to determine the presence of refractive errors and binocular dysfunctions in a population of university students. METHODS Refraction and binocular function were evaluated in a young patient population (230 students and 234 nonstudent subjects, aged 18-27 years). Distance visual acuity (DVA) and near visual acuity (NVA), refraction, cover test (CT), oc...

AIM To provide evidence that a near clinical gradient AC/A ratio could instead reflect the CA/C relationship (the accommodation driven by response to disparity). DESIGN Case control study. METHODOLOGY 27 emmetropic participants with heterophoria <4 PD, 19 with intermittent distance exotropia, and 17 with near exophoria >6 PD were tested. A remote haploscopic photorefractor, which can measur...

BACKGROUND Although eye exercises appear to help heterophoria, convergence insufficiency, and intermittent strabismus, results can be confounded by placebo, practice, and encouragement effects. This study assessed objective changes in vergence and accommodation responses in naive young adults after a 2-week period of eye exercises under controlled conditions to determine the extent to which tre...

PURPOSE Evidence exists for an additional inhibitory accommodative control system mediated by the sympathetic branch of the autonomic nervous system (ANS). This work aims to show the relative prevalence of sympathetic inhibition in young emmetropic and myopic adults, and to evaluate the effect of sympathetic facility on accommodative and oculomotor function. METHODS Profiling of ciliary muscl...