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PubMedDate not supplied

The ocular fixation index.

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Central Nervous System Diseases↗
PubMedDate not supplied

[The status of ocular fixation in civil aviation pilots].

This paper discussed the importance of gaze fixation for professional pilot activities. It describes new methods for evaluating mono- and binocular fixation. The results of examinations of pilots with mild emmetropia and ametropia demonstrate that qualitative parameters of gaze fixation are important adequate assessment of visual abilities. Fixation parameters measured using standard methods and authors' techniques have been compared. The paper presents the values of gaze fixation that require rehabilitation procedures.

Aerospace Medicine↗
PubMed1979

Nystagmus and ocular fixation difficulties in learning-disabled children.

The visual fixation ability of learning-disabled children was evaluated after sensory integrative therapy had been administered for short or long periods of time. Children with hyporesponsive postrotary nystagmus displayed reduced oculomotor control skills, but the deficit was apparent only in those who had been in therapy for a shorter interval. These results present further support for the hypothesis that the learning disabled can be differentiated according to their nystagmus characteristics. In addition, very tentative evidence suggested that sensory integrative therapy may have been successful in ameliorating the fixation deficiency; however, further research into this possibility is needed. The data also indicate that oculomotor control dysfunction may be a mediating mechanism for at least part of the learning disabilities experienced by some learning-disabled children.

Child↗
PubMed1980

The pretrigeminal cat as an instrument for investigation of the ocular fixation reflex.

The fixation reflex is an important representative of orienting (targeting) reflexes. In the cat with the brainstem transected at the pretrigeminal level the fixation reflex is easy to investigate for the following reasons: (a) all sensory inputs to the isolated cerebrum of the pretrigeminal cat are eliminated, except for visual afferents, (b) the isolated cerebrum is continuously awake, (c) the vertical fixation reflex only is present. The behavioral and neural characteristics of the fixation reflex in the pretrigeminal cat are reviewed.

Animals↗
PubMed1999

Localization of static positional nystagmus with the ocular fixation test.

OBJECTIVE: Characteristics of static positional nystagmus (SPN) (i.e., persistency, direction fixed, direction changing) are observed in both peripheral and central disturbances and possess no localizing value for vestibular lesions. Our objective was to investigate whether the ocular fixation test as applied to SPN could assist in localizing vestibular lesions. STUDY DESIGN: A 3-year prospective study that included 43 patients with SPN. METHODS: All patients underwent a standard vestibular test battery and cerebral imaging (7, computed tomography scan; 36, magnetic resonance imaging). The ocular fixation index (OFI) was calculated by the ratio of the mean slow component velocity of SPN (measured with red light-emitting diode fixation) to that measured in darkness, multiplied by 100. An OFI less than 50 was considered normal. RESULTS: In 33 of 35 patients whose OFI was less than 50, the cerebral imaging was normal and a peripheral vestibular lesion was diagnosed (two benign tumors of the fourth ventricle were missed). In all eight patients whose OFI was greater than 50, the cerebral imaging was abnormal and a central vestibular lesion was noted. CONCLUSIONS: These results indicate that the visual suppression of SPN does, indeed, permit the localization of vestibular lesions. The predictive value of the ocular fixation test on the origin of SPN is greater than 94% for peripheral lesions and 100% for central disorders.

Adolescent↗
PubMedDate not supplied

Ocular fixation to nasal periosteum with a superior oblique tendon in patients with third nerve palsy.

PURPOSE: To report a new surgical approach that uses ocular fixation to the nasal periosteum with superior oblique tendon for patients with complete third nerve palsy. METHODS: Prospective study of 15 patients with complete third nerve palsy who underwent surgery using a superior oblique tenectomy and ocular fixation to the nasal periosteum with the superior oblique tendon fragment. RESULTS: Eleven (73%) patients achieved good ocular alignment, 1 (7%) patient had a cosmetically acceptable result, and 3 (20%) patients had a cosmetically unacceptable result. Five (30%) patients had preoperative diplopia; all achieved resolution of their double vision in the primary position of gaze after surgery. Two patients without preoperative diplopia did not achieve good alignment and had diplopia postoperatively. Follow-up ranged from 8-41 months (mean: 19 months). No operative complications occurred. CONCLUSION: Ocular fixation to the nasal periosteum with superior oblique tendon is a safe, effective, and technically undemanding option for the surgical management of patients with complete third nerve palsy.

Adolescent↗
PubMed2003

Unilateral pallidotomy for Parkinson's disease disrupts ocular fixation.

Although some motor functions of the basal ganglia have been well studied, the oculomotor functions are not well established. We studied eye movements in patients with Parkinson's disease (PD) undergoing pallidotomy to assess the role of the globus pallidus interna (GPi) in oculomotor control. Horizontal visually guided, gap and predictive saccades as well as ocular fixation were studied in patients with advanced PD before and 1 month after unilateral pallidotomy, and in healthy controls on two occasions 1 month apart. There was no difference in saccadic latency or accuracy, the number of saccadic anticipations or the ability to generate predictive saccades between the two assessments for either patients or controls. The number and amplitude of square wave jerks during ocular fixation however increased significantly in patients after pallidotomy. The results imply altered function of frontal or prefrontal cortical regions involved in ocular fixation resulting from a disruption to inhibitory pallidal influences on thalamocortical projections. The posteroventral GPi however appears not to be involved in externally controlled or predictive saccadic function.

Aged↗
PubMed2006

Characterisation of ocular fixation in humans by analysis of saccadic intrusions and fixation periods: a pragmatic approach.

Eye movements during fixation were recorded in 55 normal subjects with ages ranging from 21 to 81 years. We analysed ocular fixation recordings using measurements of saccadic intrusion amplitudes and frequencies along with fixation periods and mean fixation displacement. Viewing conditions included monocular, binocular and presence or absence of a visual fixation target. Visual feedback reduced the saccadic intrusion amplitudes but had no effect on fixation periods or mean fixation displacements. Binocular viewing had no effect on saccadic intrusion amplitudes, fixation periods or mean fixation displacements. A decrease in fixation periods and an increase in the number of saccadic intrusions with age was observed. This approach could be a clinically useful tool to quantify ocular fixation in neurological disease.

Adult↗
PubMed1977

An ocular fixation device for freehand pars plana vitrectomy.

An adaptation of the stereotaxic micromanipulator is described which provides ocular support and stabilization during freehand vitrectomy. It consists of a baseplate for immobilization of the patient's head and an ocular fixation arm assembly which connects to the eye by grasping a special Flieringa ring sewed to the postlimbal sclera. The ocular fixation arm can be made alternately flexible or rigid, thereby providing needed ocular mobility or stability during the operation as is desired by the surgeon.

Ciliary Body↗