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At least 1,711 records · Page 95Linked to original sources
PubMed1986

[Site and depth of glaucomatous visual field defects in relation to the size of the neuroretinal edge zone of the optic disk in glaucoma without hypertension, simple glaucoma, pigmentary glaucoma. A clinical study with the Octopus perimeter 201 and the optic nerve head analyzer].

The size of the neuroretinal rim area of the disk was measured with the Optic Nerve Head Analyzer in 57 eyes of 57 patients with low-tension glaucoma (LTG), glaucoma simplex (POAG), and pigmentary glaucoma. The visual fields were examined with Program 33 or 31 (30 degrees eccentricity, 6 degrees grid) of the Octopus 201 Perimeter. The mean sensitivity loss per test point in the central field, in the field quadrants, and in the ranges from 0 degrees-10 degrees, 10 degrees-20 degrees, and 20 degrees-30 degrees were calculated with the Delta program. In addition, the mean loss per disturbed point, which gives the mean depth of scotomata, was calculated. In LTG a larger vertical cup/disk ratio (CDR) was found than in POAG for the same amount of total loss. The comparison of eyes with neuroretinal rim areas of equal size revealed that in contrast to POAG and pigmentary glaucoma, eyes with LTG had a smaller mean sensitivity loss; deeper, more localized scotomata; more visual field defects in the lower field in the initial stages; more scotomata in the area up to 20 degrees. The differences between glaucoma with and without high intraocular pressure were found to be most pronounced in the initial stages of the disease. These differences appear to be caused by the varying amounts of vascular pathogenesis involved. Therefore, at least two pathomechanisms have to be considered in glaucoma.

Glaucoma, Open-Angle↗
PubMed1990

[Modified technics for the examination of the central visual field].

The quantitative evaluation of small central and paracentral scotomas is a problem. Examination of the central visual field with an automatic or semiautomatic field analyzer can lead to a great number of false-positive results. Therefore, we have tried to develop two modifications of perimetric techniques: they allow continuous variation of the light intensity and quantitative recording of relative scotomas. For the investigation we used the well-known caro grid. With a new arrangement of the grid lines, it is possible to analyze nerve fibre scotomas. The results of the new perimetric techniques are presented.

Adult↗
PubMed2005

The eyes of a patrolling butterfly: visual field and eye structure in the Orange Sulphur, Colias eurytheme (Lepidoptera, Pieridae).

Sensory information plays a critical role in determining an animal's behavior on both proximate and evolutionary timescales. Butterflies, like many other insects, use vision extensively over their lifetimes, and yet relatively little work has been published to date on their visual capabilities. We describe the visual system of a pierid butterfly, Colias eurytheme, with the ultimate goal of better understanding its role in shaping the behavior of this animal. We made several measurements: visual field dimensions, eye surface area, interommatidial angle (Deltaphi), facet diameter (D), and eye parameter (p). C. eurytheme had a large visual field and considerable regional variation in visual acuity, as inferred by Deltaphi and D. When compared to females, males had larger eye surface areas, smaller Deltaphi, and larger D in all regions except ventrally. Both sexes had proportionally large eye surface areas compared to other butterflies. Minimum p in males was small, indicating that some regions of their eyes may operate close to the diffraction limit. Finally, we found that both eye surface area and D scaled positively, but with negative allometry to body size. We discuss the relevance of these visual characteristics to the biology and behavior of C. eurytheme.

Animals↗
PubMed1992

Mutual rod-cone suppression within the central visual field.

Under mesopic conditions the contrast sensitivity of the central visual field is reduced as the result of a non-linear interaction between rod- and cone-mediated signals, each of which is capable of higher sensitivity in isolation. The interaction is produced only when the rod-mediated system is driven at flicker rates above 6 Hz. This finding bears upon how rod and cone signals are combined and therefore affects our interpretation of the significance of the relationship between retinal illuminance and both contrast sensitivity and temporal resolution.

Contrast Sensitivity↗
PubMed2001

Nerve fiber bundle visual field defect resulting from a giant peripapillary cotton-wool spot.

Cotton-wool spots are the clinical manifestation of focal infarcts of the retinal nerve fiber layer. They rarely cause significant visual field loss. A large idiopathic cotton-wool spot in a 34-year-old healthy woman caused a nerve fiber bundle visual field defect and an afferent pupillary defect that remained after the cotton-wool spot had disappeared and the retina and optic nerve appeared normal.

Adult↗
PubMed2006

Relationship between patterns of visual field loss and retinal nerve fiber layer thickness measurements.

PURPOSE: To investigate the association between patterns of visual field (VF) loss and retinal nerve fiber layer (RNFL) thickness measurements. DESIGN: Observational cross-sectional study. METHODS: One hundred twenty-one glaucoma patients and 65 healthy subjects from the Diagnostic Innovations in Glaucoma Study (DIGS) were included. All glaucoma patients had repeatable abnormal VFs and scanning laser polarimetry (SLP) RNFL thickness measurements. RNFL measurements were obtained from 16 equal parapapillary sectors. Patterns of VF loss were classified as arcuate, partial arcuate, nasal step, or paracentral in each VF hemifield. Logistic regression analysis was performed to determine which RNFL sectors were associated with each VF pattern. The ability of SLP to discriminate between eyes with different VF patterns and healthy eyes using receiver operating characteristic (ROC) curve analyses also was investigated. RESULTS: VF patterns in the superior hemifield were significantly associated with RNFL sectors in the temporal inferior hemiretina (P < .05). ROC curve areas for discrimination between eyes with different VF patterns and healthy eyes ranged from 0.85 to 0.95. VF patterns in the inferior hemifield were most strongly associated with temporal superior RNFL sectors (P < .05). ROC curve areas for discrimination between different VF patterns and healthy eyes ranged from 0.73 to 0.98. SLP could discriminate between apparently unaffected VF hemifields in glaucoma eyes and VF hemifields in healthy eyes. CONCLUSIONS: Parapapillary RNFL thickness was topographically related to patterns of VF loss. SLP can differentiate between apparently unaffected VF hemifields in glaucoma eyes and normal VF hemifields in healthy eyes.

Aged↗
PubMed1989

Comparison of different screening methods for the detection of visual field defects in early glaucoma.

The effectiveness of three different automated perimetry strategies for the screening of glaucomatous visual field defects was studied on 182 eyes of glaucoma suspects. The results were compared with those obtained with the Octopus G1 program. On this particular sample of population the results are as follows. Henson perimeter: sensitivity 59.4%, specificity 88%. Humphrey perimeter (Armaly full field test): sensitivity 64.2%, specificity 64.2%. Perikon perimeter (Genoa glaucoma screening): sensitivity 55%, specificity 90.4%. Octopus perimeter (G1 program): sensitivity 92.1%, specificity 83%.

Glaucoma↗
PubMed1975

[Changes of the visual field with cerebral tumors].

Neurosurgical material of 1,746 tumours is reviewed for the relations between operative and post mortem localization of cerebral tumours and pathological findings of isopteric perimetry; and the incidence of defects of the visual field with the different localizations of tumours is discussed. The aim was to localize the tumours as accurately as possible. At least in brain tumour patients the defect of the visual field does not allow conclusions on the level of lesions to the visual pathway. Only the superior quadranopsia is important for the temporal localization.

Blindness↗
PubMed2002

Visual field deficit caused by vascular compression from a suprasellar meningioma: case report.

OBJECTIVE AND IMPORTANCE: Suprasellar meningiomas typically cause bitemporal hemianopsia by direct compression of the chiasm, its blood supply, or both. We report another mechanism for visual loss in suprasellar meningiomas, whereby compression by the suprajacent vascular complex is the offending agent. CLINICAL PRESENTATION: A 78-year-old woman with a suprasellar meningioma was diagnosed incidentally. During the follow-up period, she developed an inferior homonymous wedge defect consistent with superior compression, without any detectable radiological progression. It was decided to resect her tumor. INTERVENTION: The patient underwent a fronto-orbital approach for tumoral excision. Intraoperatively, a groove by the anterior cerebral artery complex was found along the superior surface of the chiasm. Postoperatively, the patient's visual deficit resolved. CONCLUSION: This case illustrates an unusual visual field deficit associated with a suprasellar meningioma. It also emphasizes the importance of frequent and careful visual field monitoring, which can precede radiological and symptomatic progression.

Aged↗
PubMed1995

New approach to estimating variability in visual field data using an image processing technique.

AIMS: A new framework for evaluating pointwise sensitivity variation in computerised visual field data is demonstrated. METHODS: A measure of local spatial variability (LSV) is generated using an image processing technique. Fifty five eyes from a sample of normal and glaucomatous subjects, examined on the Humphrey field analyser (HFA), were used to illustrate the method. RESULTS: Significant correlation between LSV and conventional estimates--namely, HFA pattern standard deviation and short term fluctuation, were found. CONCLUSION: LSV is not dependent on normals' reference data or repeated threshold determinations, thus potentially reducing test time. Also, the illustrated pointwise maps of LSV could provide a method for identifying areas of fluctuation commonly found in early glaucomatous field loss.

Adult↗
PubMed1990

Equating character-identification performance across the visual field.

The effect of retinal eccentricity on stimulus identification was investigated by measuring observers' ability to identify digits of various sizes presented briefly at different locations in their visual fields. The stimuli were either presented one at a time or presented in pairs with each member of the pair at a different eccentricity and having a different size. Stimulus-response confusion matrices were used to calculate the information transmitted by each character as a function of stimulus size and retinal eccentricity. Linearly scaling stimulus size with retinal eccentricity yields equal information transmission across each subject's visual field. There was no difference between the amounts of information transmitted when the targets were presented alone and when they were transmitted in pairs. For small target sets, therefore, the amount of information transmitted from the screen to the observer can be approximated as the sum of the information at the separate locations.

Humans↗
PubMed2003

Attention-dependent coupling between beta activities recorded in the cat's thalamic and cortical representations of the central visual field.

We have previously proposed that enhanced 16-24 Hz (beta) local field potential activity in the primary visual cortex and lateral geniculate nucleus may be an electrophysiological correlate of the attentional mechanism that increases the gain of afferent visual information flow to the cortex. In this study, we measured coupling between beta signals recorded in the thalamic (i.e. lateral geniculate or perigeniculate) and cortical representations of the central visual field (within 5 degrees from area centralis), during visual and auditory attentive situations. Signal coupling was calculated in two ways: (i) by means of crosscorrelation between raw beta activities, which depends primarily on phase coherence, and (ii) by phase-independent crosscorrelation between amplitude envelopes of beta activities. Mean amplitudes of raw signal cross correlations obtained for thalamo-cortical recording pairs were not significantly different when calculated during behavioural demands for either visual or auditory attention. In contrast, amplitudes of envelope cross correlations obtained during behaviour requiring visual attention were, on average, two times higher than those calculated during the auditory task. This attention-related coupling emerged from synchronized amplitude modulation of beta oscillatory activity that occurs within the cortico-thalamic circuit involved in central vision.

Acoustic Stimulation↗
PubMed1975

[Differential diagnosis of bitemporal paracentral visual fields defects in "low-tension glaucoma" and tumors of the pituitary gland (author's transl)].

A 46-year-old patient shows paracentral scotomas in the oblique meridians of the visual fields. Additionally there exists pathologically cupped, atrophical disks which lead to the tentative diagnosis of "low-tension glaucoma". As the scotomas are bitemporally located a tumor near the chiasm must be the cause for these field defects. During the operation a chromophobe adenoma of the pituitary gland was found in the patient. We pointed out that even arcuate scotomas which cross the vertical meridian of the visual field can be caused by an intra- or parasellar tumor. As Hoyt has shown in his investigations in animals one could suppose that these scotomas can be developed from direct compression of the chiasm.

Adenoma↗
PubMed2001

Invariance of the psychometric function for character recognition across the visual field.

The psychometric function for recognition of singly presented digits as a function of digit contrast was measured at 2 degrees steps across the horizontal meridian of the visual field, under monocular and binocular viewing conditions. A maximum-likelihood staircase procedure was used in a 10-alternative forced-choice recognition paradigm to gather the data Both the Weibull and the logistic psychometric functions provide excellent fits to the observed data. The slopes of these functions at their point of inflection ranged from 4.0 to 5.0 proportion-correct/log10-unit contrast, for both monocular and binocular viewing and for all loci in the visual field. These slope values correspond to short-term measurements (around 30 trials, or 1 min) and do not include performance variations of longer duration; the latter are estimated to increase slope by a factor of about 1.5. A single psychometric function shape, centered around a threshold value, therefore describes recognition performance at all retinal loci and binocularity. An empirical comparison of slope results across the literature shows that the function's slope is about twice that reported for a number of detection tasks. The comparison of recognition contrast thresholds, percentage correct values, and other performance measures across studies requires the knowledge of the psychometric function's slope, and our results thus provide a firm basis for the study of low-contrast character recognition.

Adult↗
PubMed2003

Detection of glaucomatous visual field defect by nonconventional perimetry.

PURPOSE: To report the correlations among Humphrey Field Analyzer 750 (HFA), high-pass resolution perimetry (HRP), and frequency-doubling technology (FDT) perimetry in glaucoma patients and ocular hypertensive patients. DESIGN: Cross-sectional study. METHODS: Eighty-two eyes of 82 consecutive patients with primary open-angle glaucoma (POAG) or ocular hypertension were included in this study. One eye of each patient was randomly selected for data analysis. Visual fields were assessed by HFA, HRP, and FDT perimetry. HRP global deviation (HRP-GD), HRP local deviation (HRP-LD), FDT-mean deviation (FDT-MD), and FDT-pattern standard deviation (FDT-PSD) were considered for the analysis. Clinical agreement between HRP and FDT was evaluated. All data were analyzed by Pearson r coefficient when the distribution of the data was normal and by Spearman coefficient correlation when the distribution of the data was not normal. A P <.05 was considered statistically significant. RESULTS: Fifty-two eyes (52 patients) were classified as glaucoma and 30 eyes (30 patients) as ocular hypertension. In the entire group, a significant (P >.001) correlation was found between the HFA indices and those of either HRP or FDT. A significant (P <.001) correlation was found between HRP-GD and FDT-MD as well as between HRP-LD and FDT-PSD. In 14% of the glaucomatous patients and in 33% of the subjects with ocular hypertension, FDT and HRP showed different clinical features. CONCLUSIONS: Our data suggest that FDT and HRP are useful for detection of early glaucomatous visual field damage.

Aged↗
PubMed1986

Rapid improvement in visual field defects following bromocriptine treatment of patients with non-functioning pituitary adenomas.

The role of bromocriptine in the treatment of non-functioning pituitary tumours is not yet defined. Patients with these tumours who present with visual field defects usually undergo immediate surgery. Three consecutive patients are reported: each had rapid improvement in their visual field defects following bromocriptine 7.5 mg/d before surgery. Histological and immunohistochemical examination confirmed that their tumours were non-functioning chromophobe adenomas. Their responses indicate that bromocriptine may have a role in the management of some patients with non-functioning pituitary tumours.

Adenoma, Chromophobe↗
PubMed2006

Prevention of visual field defect progression with angiotensin-converting enzyme inhibitor in eyes with normal-tension glaucoma.

PURPOSE: To report the effect of angiotensin-converting enzyme (ACE) inhibitor on visual field changes in normal-tension glaucoma (NTG). DESIGN: Retrospective observational case series. METHODS: We retrospectively reviewed a total of 38 patients with NTG. Control subjects had no previous history of hypertension. NTG hypertension patients were divided into two groups, those receiving ACE inhibitor and those receiving other antihypertensive drug treatments. HfaFiles 5, an analytical program for the Humphrey Field Analyzer, was used to calculate the slope for the mean deviation (MD) change per year. RESULTS: In the ACE inhibitor-treated group, the mean MD change per year was 0.48 +/- 0.19 dB, in control subjects was -0.38 +/- 0.23 dB, and in the other antihypertensive drug-treated group was -0.50 +/- 0.39 dB. CONCLUSIONS: Although the present study is retrospective and the sample size is small, ACE inhibitor might have a favorable effect on the visual field in patients with NTG in this small study.

Aged↗