purpose: the goal of this study was to compare differences in the mean heterophoria and fusional amplitudes before and after photorefractive keratectomy (prk) for myopia. methods: in a prospective controlled study, myopic patients were treated with aspheric and wavefront-guided (personalized) prk. the manifest refraction, visual acuity, fusional amplitudes and heterophoria were evaluated preope...

purpose : to determine the fusional amplitudes and the frequency of hetrophoria, in our patients methods : in this cross sectional study, 111 adults with mean age of 25.6 years were included. all participants had best corrected visual acuity (bcva) better than 20/25, more than 60 sec of arc stereopsis and had no heterotropia or other significant eye disorders. fusional amplitudes were measured ...

Foveal stimuli were used to elicit fusional convergence movements of the left eye in 5 subjects icith normal binocular vision. The amplitude of fusional convergence was measured by recording eye position. The eyes were light adapted, and the stimulus to the left eye was driven at angular velocities ranging from 1/8 to 6 degrees per second. Although large individual differences were found in the...

The stability of binocular vision depends on good fusional amplitudes. These amplitudes are the result of a reflex arc, the sensory stimulus being caused by the images of the object of regard falling off one fovea. If this image falls outside Panum's area, diplopia will result. The motor response involves a movement of one or both eyes to maintain fusion and avoid diplopia. The afferent sensory...

Two special slides, one in front of one eye and one in front of the other eye, were placed in the housings of a synoptophore. The slides were originally designed for the diagnosis and measurement of cyclodeviation, but they were utilised in this study for the measurement of torsional fusional vergence. This was measured by rotating one of the housings of the synoptophore and noting the point of...

Acquired central disruption of fusional amplitude is characterized by a complete loss of fusional amplitude, the patient maintaining fusion for only a moment under test conditions before breaking to constant diplopia. Under normal viewing conditions, the patient has constant diplopia with both eyes open. Patients who have bilateral superior oblique palsy may mimic this loss of fusion and consta...

IT is generally accepted that nearly all patients with fixed small-angle convergent strabismus and bilateral central fixation show harmonious anomalous retinal correspondence (h.a.r.c.) when examined in normal surroundings under nondissociating test conditions (Bagolini's striated glasses) (Bagolini and Tittarelli, 1960; Pasino and Maraini, 1962). H.a.r.c. has been shown to adapt itself quite e...

Purpose: There are a few researches regarding the effects of Islamic fasting on visual system. The aim of this study was to investigate the effects of Ramadan fasting on the amplitude of accommodation (AA), near point of convergence (NPC), positive and negative fusional vergences (PFV and NFV, respectively) in visually healthy fasters. Methods: AA, NPC, PFV and NFV at far (6m) and near (40cm) w...

Types of Convergence (1) Voluntary Convergence – Amount of Convergence of visual axes that can be produced at will (2) Reflex convergence Convergence of visual axes which is not under complete voluntary control and it has four components – a. Tonic convergence – Due to inherent innervational tone of extra ocular muscles. b. Fusional convergence -The convergence that is produced to ensure that s...

INTRODUCTION Orthoptic exercises have been the primary treatment for convergence insufficiency since this condition's first description in 1855. It is presumed that exercises work by improving fusional convergence. In recent years, research from eye movement laboratories has challenged our theories on the nature and dynamics of convergence, the effect of convergence exercises, and the etiology ...