PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Visual Fields”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12Linked to original sources
PubMed1992

[Age-related changes in the normal visual field using colored targets].

The authors evaluated the influence of aging on the normal visual field sensitivity and the color visual field sensitivity. The central 5 degrees visual field of 259 normal subjects (ages 10 to 79) was evaluated with Program Macula of the Humphrey Field Analyzer. Visual field sensitivity remained constant, irrespective of age, until 40 years. In contrast, sensitivity decreased linearly with aging after 40 years. The age-related decline of visual field sensitivity was most remarkable using a blue target. Visual field sensitivity gradually decreased toward the peripheral retina measured by white, red and green targets. However, using a blue target, at 1 degree-2 degrees locations from the fovea, sensitivity was the same as foveal sensitivity. There were no statistically significant differences of visual field sensitivity between the lower half of visual field and the upper half, and between the temporal half and the nasal half. At all test locations, the ordering of visual field sensitivity was white > red > blue > green target.

Adolescent↗
PubMed1999

[Causes of visual field defects after vitrectomy].

PURPOSE: An inferotemporal visual field defect sometimes occurs following vitreous surgery for idiopathic macular hole. There is a possibility that this visual field defect is due to damage to the superonasal retina by fluid or air irrigation through an inferonasal infusion port. We tested this hypothesis by placing the infusion port in the inferonasal sector during vitreous surgery. CASES AND METHOD: We performed vitreous surgery on 31 eyes with idiopathic macular hole. The infusion port was placed in the inferonasal sector. The vitreous cavity was replanced either by 20% SF6 or 12% C3F8. We did not abrade the retinal pigment epithelium within the hole. The visual field was assessed before and 1 month after surgery using a Goldmann perimeter. FINDINGS: Three eyes developed a wedge-shaped visual field defect in the inferonasal sector. No visual field defect developed in the other 28 eyes. CONCLUSION: The findings show that visual field defect following surgery for idiopathic macular hole is dependent upon the site of the infusion port. We presume that the visual field defect is consequent to retinal damage caused by the flow of air or fluid during surgery.

Aged↗
PubMed2000

Competition-induced visual field differences in search.

Do visual field effects point to differences in cortical representation, or do they reflect differences in the way these representations are used by other brain regions? This study explored three attributes of visual search that provide strong evidence in favor of differences in use. Competition refers to the finding that visual field differences in search efficiency are larger in whole- than in half-field displays (both left-right and upper-lower half-fields). Task specialization refers to the finding that some tasks favor one hemisphere whereas other tasks favor the other hemisphere, even though the same stimulus displays are used in both tasks. Anatomical alignment refers to the finding that competition effects are altered if the quadrants of the visual display are not aligned with the cortical quadrants of the observer. We propose that visual field specialization in search is the result of a competition involving limited access to cortical visual representations by the extended neural networks of attention.

Adult↗
PubMed2002

Properties of receptive field on binocular fusion stimulation in the central visual field.

BACKGROUND: Visual information projected onto corresponding points on the right and left retinas converges on the binocular cells in the visual cortex. The aim of this study is to investigative the characteristics of the receptive field for binocular stimulation in the central visual field of normal-sighted human subjects. METHODS: We investigated the receptive field for binocular stimulation under fusion conditions by combining the Octopus 201 with the space synoptophore. We measured binocular and monocular sensitivities while the fusion patterns were projected onto the Octopus 201 cupola, using the space synoptophore. We designed a new program to test 37 points in the central 6 degrees visual field. Six target sizes were tested: the white-spot targets of 0.054 degrees, 0.108 degrees, 0.216 degrees, 0.431 degrees, 0.862 degrees and 1.724 degrees projected diameters. RESULTS: The threshold energy necessary for binocular stimulation was lower than that for the monocular stimulation in all subjects. This difference was more obvious on the test points that were more distant from the fovea when target sizes of 0.054 degrees and 0.108 degrees were used. The amount of binocular summation ratio was highest for target size 0.054 degrees in each stimulus area in the central 6 degrees of the visual field. When we measured binocular summation using target sizes larger than 0.108 degrees, the result was the constant summation. CONCLUSIONS: The size of the receptive field for binocular stimulation is smaller than monocular stimulation under the same fusion condition. The amount of binocular summation varies as a function of target size.

Adult↗
PubMed1988

A comparison of experienced clinical observers and statistical tests in detection of progressive visual field loss in glaucoma using automated perimetry.

The visual fields of 30 patients (subjects) with glaucoma were sent to six experienced clinicians (observers). Each subject had at least four visual field examinations on the OCTOPUS 201 automated perimeter spanning at least one year. Each observer was asked to review the visual field data of each subject and determine whether the visual fields were stable, improved, or worse over time. The visual field data were then analyzed using six different statistical models. In only 15 of the 30 subjects did at least five of the six human observers agree on the behavior of the visual field. Agreement among the statistical models was better, with at least five of the six models agreeing on 22 of the 30 subjects. It was concluded that there is, at present, no validated technique for detecting progressive visual field loss in glaucoma using automated perimetry when relatively few visual fields are available for analysis.

Analysis of Variance↗
PubMed1993

Quality control functions of the Visual Field Reading Center (VFRC) for the Optic Neuritis Treatment Trial (ONTT).

The Visual Field Reading Center (VFRC) was established to assess visual field testing in the Optic Neuritis Treatment Trial (ONTT), to train and certify ONTT technicians, and to monitor the quality of the visual fields through evaluation of the technical aspects of the visual field testing. We describe the functions of the VFRC personnel and the standardized test protocols developed by the VFRC for Humphrey and Goldmann perimetry. We also describe the VFRC procedures for training and certifying visual field technicians, double-checking the eligibility of ONTT patients, assessing the quality of the visual field data, and processing visual field data. In addition, we describe the principles applied by the director and associate director of the VFRC in their clinical classification of the various localized and diffuse visual field defects observed in the Humphrey and Goldmann visual fields. The VFRC has processed more than 14,000 Humphrey and Goldmann visual field tests. The visual field quality control procedures and visual field defect classification process have been shown to be quite reproducible. Through quality control assessment procedures, we have been able to pinpoint a variety of problems at an early stage and promptly implement corrective measures. The standardized test protocols, technician training and certification procedures, and quality control assessment techniques used by the VFRC for the ONTT may serve as a model for future clinical trials employing visual field data as an outcome measure. These procedures can also be used to enhance visual field reliability in ophthalmological practices.

Education↗
PubMed2002

Pupil perimetry in the diagnosis of functional visual field loss.

The diagnosis of functional visual loss-reduced visual performance in the absence of an organic cause-is usually made by exclusion. We conducted a pilot study to evaluate pupil perimetry in three patients (aged 14, 43 and 50) with visual field loss presumed to be functional on clinical grounds and having no cause identified by visual electrophysiology or magnetic resonance imaging. A modified automated perimeter was used to examine visual and pupil responses to a light stimulus (size 1.7 degrees ) presented at five locations in the visual field (fixation and in each of the four quadrants). In each patient, the pupil responses were normal in those test quadrants which showed apparent visual field loss. Pupil perimetry provides objective evidence for a diagnosis of functional visual field loss in selected patients and may circumvent the need for other investigations.

Adolescent↗
PubMed1986

[Glaucoma visual fields and filtering operations].

Visual field defects already existing in 81 eyes prior to goniotrepanation (Elliot-Fronimopoulos) were followed up for up to 84 months postoperatively. In 11 eyes there were slight peripheral limitations due to cataract formation. In all of the other cases the visual fields were unchanged.

Follow-Up Studies↗
PubMed1982

Length perception in degeneratio pigmentosa retinae cases and normal subjects with limited visual field.

To investigate quantitatively the visual disturbance in cases of degeneratio pigmentosa retinae, the effect of the visual field size on length perception was studied. In the experiment, 3 patients were asked to compare the length of two lines presented on the screen for 5 seconds under monocular and free viewing conditions. The difference threshold value for stimulus length was estimated by the descending method of limit. Three normal subjects participated in this experiment under two conditions; one was the free viewing condition mentioned above and the other was a limited visual field condition. In the latter case, subjects viewed through a pinhole on the Lo-Vac contact lens. With this contact lens, they had almost the same visual field size and visual acuity as the patients. In these cases, subjects could move the eye and head freely. The results suggested that accurate length comparison is possible only when the lines are perceived simultaneously.

Adult↗
PubMed2001

Representation of the visual field in the lateral intraparietal area of macaque monkeys: a quantitative receptive field analysis.

The representation of the visual field in the primate lateral intraparietal area (LIP) was examined, using a rapid, computer-driven receptive field (RF) mapping procedure. RF characteristics of single LIP neurons could thus be measured repeatedly under different behavioral conditions. Here we report data obtained using a standard ocular fixation task during which the animals were required to monitor small changes in color of the fixated target. In a first step, statistical analyses were conducted in order to establish the experimental limits of the mapping procedure on 171 LIP neurons recorded from three hemispheres of two macaque monkeys. The characteristics of the receptive fields of LIP neurons were analyzed at the single cell and at the population level. Although for many neurons the assumption of a simple two-dimensional gaussian profile with a central area of maximal excitability at the center and progressively decreasing response strength at the periphery can represent relatively accurately the spatial structure of the RF, about 19% of the cells had a markedly asymmetrical shape. At the population level, we observed, in agreement with prior studies, a systematic relation between RF size and eccentricity. However, we also found a more accentuated overrepresentation of the central visual field than had been previously reported and no marked differences between the upper and lower visual representation of space. This observation correlates with an extension of the definition of LIP from the posterior third of the lateral intraparietal sulcus to most of the middle and posterior thirds. Detailed histological analyses of the recorded hemispheres suggest that there exists, in this newly defined unitary functional cortical area, a coarse but systematic topographical organization in area LIP that supports the distinction between its dorsal and ventral regions, LIPd and LIPv, respectively. Paralleling the physiological data, the central visual field is mostly represented in the middle dorsal region and the visual periphery more ventral and posterior. An anteroposterior gradient from the lower to the upper visual field representations can also be identified. In conclusion, this study provides the basis for a reliable mapping method in awake monkeys and a reference for the organization of the properties of the visual space representation in an area LIP extended with respect to the previously described LIP and showing a relative emphasis of central visual field.

Animals↗
PubMed2005

Inapparent visual field defects in multiple sclerosis patients.

To assess inapparent visual field defects in patients with multiple sclerosis free from optic neuritis. During 5 years period 120 patients with multiple sclerosis were examined at the University Department of Ophthalmology, Zagreb University Hospital Center. They were divided into three groups with 40 patients each: patients with acute unilateral optic neuritis, referred to ophthalmologist and treated with pulsed steroid therapy; patients with subjective feeling of blurred vision, normal visual acuity and no signs of acute optic neuritis; and patients free from subjective signs of visual impairment. Study patients underwent standard ophthalmologic examination and visual field testing in photopia by use of quantitative kinetic Goldmann perimetry. The initial and control examination by visual field testing were performed at least 6 months apart. Study results showed 65% of multiple sclerosis patients to have visual field defects without subjective signs of impaired vision. The most common defects were mild to moderate visual field narrowing with blind spot enlargement and depression from above. The following results were recorded: acute optic neuritis group: normal in 13/40 (32.5%) for the affected eyes and 27/40 (67.5%) for fellow eyes; mild visual field narrowing in 4/40 (10%) for the affected eyes and 10/40 (25%) for fellow eyes; moderate visual field narrowing with blind spot enlargement in 14/40 (35%) for the affected eyes and 1/40 (2.5%) for fellow eyes; and paracentral and arcuate scotomata in 9/40 (22.5%) for the affected eyes and 2/40 (5%) for fellow eyes; subjective symptom group: normal in 8/40 (20%) for the affected eyes and 11/40 (27.5%) for fellow eyes; mild visual field narrowing in 11/40 (27.5%) for the affected eyes and 16/40 (40%) for fellow eyes; moderate visual field narrowing with blind spot enlargement in 18/40 (45%) for the affected eyes and 10/40 (25%); andparacentral and arcuate scotomata in 3/40 (7.5%) for both affected and fellow eyes; and subjective symptom-free group: normal in 24/80 (30%), mild visual field narrowing in 22/80 (27.5%) moderate visual field narrowing with blind spot enlargement in 24/80 (30%); and paracentral and arcuate scotomata in 10/80 (12.5%). The presence of subclinical form of optic nerve involvement could be demonstrated in a very early stage of multiple sclerosis by the introduction of visual field testing in the standard examination protocol.

Adolescent↗
PubMed2003

Laser pointer visual field screening.

BACKGROUND: Sensitivity of confrontation visual field (CVF) screening is low unless defects are significant. We compared the sensitivity of laser pointer visual field screening (LVF) with conventional CVF for identifying eyes with abnormal automated perimetry. METHODS: Ninety consecutive patients presenting for HVF prospectively underwent a masked comparison of CVF and LVF testing (175 eyes) from April to May 2000. LVF was performed using a laser pointer target projected onto a tangent screen. Points were tested in random fashion on either side of the vertical and horizontal meridians, near central fixation, around the blind spot, and in each quadrant. Single and double simultaneous finger counting was used to test CVF. RESULTS: LVF demonstrated significantly greater sensitivity as compared with CVF (73% versus 31%, P = 0.001) in identifying field defects found on HVF. Specificities for LVF and CVF were 82% and 99%, respectively. The average testing times per eye were 0.5 minute for CVF, 1.5 minutes for LVF, and 8.0 minutes for HVF. CONCLUSIONS: In this cohort, laser visual field testing was significantly more sensitive than confrontation testing. It may represent an effective, time-efficient tool for visual field screening.

Cohort Studies↗
PubMed1981

[Reasons for postoperative deterioration of visual fields in cases of advanced primary open-angle glaucoma (author's transl)].

In 86 patients suffering from advanced glaucomatous field defects visual functions were evaluated up to 12 years postoperatively. There was a 50% deterioration in visual acuity in 29 eyes (34%). This was mainly caused by new cataract formation. Visual fields were examined on the Tübingen perimeter. In 12 out of 80 eyes there was suspected deterioration and in another 28 eyes (35%) confirmed deterioration. In no case did surgery cause the preoperative field to disintegrate. The deterioration, which usually accelerates slowly, is a consequence of general vascular diseases such as diabetes mellitus, arteriosclerosis or hypertonia.

Diabetes Complications↗
PubMed1983

Visual field defects in idiopathic intracranial hypertension (pseudotumor cerebri).

Idiopathic intracranial hypertension (pseudotumor cerebri) produces loss of visual field and visual acuity. We conducted a retrospective study of 12 patients (all female, ranging in age from 6 to 44 years) using computerized visual field analysis. In seven of the 12 patients, the visual field loss appeared to be permanent, and follow-up was too short for the final outcome to be determined in two others. The visual field defects were those known to be associated with optic disk lesions. The most common were blind spot enlargement (all 12 cases), isopter constriction (nine cases), and loss on the nasal side of the visual field (seven cases), especially in the inferonasal quadrant. Four patients had diminished visual acuities. The reversibility of the visual field defects was correlated with the presence (nonreversible) or absence (reversible) of ophthalmoscopic signs of chronic papilledema. Because visual loss is reversible if treatment is begun before the onset of the optic disk changes associated with chronic papilledema, patients with idiopathic intracranial hypertension should be monitored carefully with frequent perimetric and visual acuity testing.

Adult↗
PubMed1979

Visual-field asymmetries in letter recognition: evidence for asymmetry in early visual registration.

Two experiments on visual-field differences in tachistoscopic letter recognition are described. In the first, a bright pre-exposure field with a black fixation point was used, and the conventionally expected dominance of the right visual field was found. However, a large number of "blank" trials were observed, in which subjects completely failed to detect the presence of the flashed target. These "blanks" were themselves significantly asymmetric between visual fields, suggesting that asymmetry in early stimulus registration may play an unsuspected role in typical measures of cerebral asymmetry in recognition accuracy. This was confirmed in a second experiment in which use of dark pre-exposure fields eliminated "blanks" and led to higher over-all accuracy, with no visual-field differences. Implications for interpretation of laterality data with normal subjects are discussed.

Adult↗
PubMed1989

[Visual perception in normal children and adults I. Developmental changes in dominance of visual field in normal children].

Developmental changes of dominance of visual field was evaluated using a tachistoscope in 70 normal subjects from 4 years of age up to adulthood (35 males and 35 females). The time of exposure was measured under two experimental conditions; simultaneous stimulation of different types to both left and right fields, or a single stimulus only to one visual field. One of the following stimuli was exposed to the visual field; one, two or three letters of Japanese characters ("hirakana"), one of Chinese characters ("kanji"), figures, and Roman alphabets. Simultaneous bilateral stimulation revealed frequent dominance in the right visual field, which was established by 4 years of age. The average time of exposure become shorter with age up to 6-7 years for one "hirakana" letter and one "kanji", and up to 10 years for two and three "hirakana" letters. All four left-handed subjects in this study showed dominance of the right visual field. Dominance of the left visual field was observed in 3 of 52 subjects with dominance of the right eye (5.8%), and in 5 of 15 with dominance of the left eye (33.3%). This difference was statistically significant (chi 2 = 8.41, p less than 0.01). It was suggested that dominance of the visual field was related with dominance of the eye, and not with handedness.

Adolescent↗