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At least 829 records · Page 46Linked to original sources

PubMed2002

Detection of visual field defects in patients after anterior temporal lobectomy for mesial temporal sclerosis-establishing eligibility to drive.

AIMS: The aim of this study is to quantify visual field defects after temporal lobectomy for mesial temporal sclerosis and to establish eligibility for driving. METHODS: Automated static perimetry was performed on 14 patients who had undergone anterior temporal lobectomy for mesial temporal sclerosis. Perimetry consisted of monocular Humphrey Field Analyser (HFA) 30-2 test and a binocular Esterman 120 test. RESULTS: Of the 14 patients, three had no loss or non-specific loss, eight had partial homonymous quadrantanopia, one had complete homonymous quadrantanopia and two had concentric loss attributable to vigabatrin, which may have masked any loss occurring due to surgery. Of these, only seven passed the standardised DVLA visual fields. Of the seven who failed DVLA visual field, one had complete quadrantanopia, four had partial quadrantanopia and two had concentric loss (due to vigabatrin). CONCLUSIONS: Visual field defects contribute a great deal in the reduction of the quality of life in patients who have had surgery for mesial temporal sclerosis. Potential surgically induced visual field defects that could preclude driving need to be discussed with each patient preoperatively. In our study 50% of patients did not meet the required DVLA standards.

Adult↗

PubMed2000

[A study on correlation between the structural parameter of optic disc and visual field in primary open-angle glaucoma].

OBJECTIVE: To study the consistency between the optic disc neural rim depth (NRD) and visual field defect in patients with primary open angle glaucoma (POAG). METHODS: A system of computerized image analysis was used to measure the relative NRDs of temporal-superior and temporal-inferior area of the optic disc in patients with primary open angle glaucoma. The consistency between the area with relatively larger NRD and the location of severer visual field defect was investigated. RESULTS: In cases with early and middle stage POAG, the value of NRD corresponding to the severer location of the visual field defect was significantly larger than that corresponding to the location without or with mild such defect. Among 54 eyes, there were 46 eyes whose location with larger NRD value was consistent with the position of severer visual field defect, the rate of consistency being 85.2%. CONCLUSION: In cases with early and middle stage POAG, the increase of NRD value at temporal-superior and temporal-inferior area is asymmetrical, and the consistency between the area with larger NRD value and the corresponding position of severer visual field defect is relatively good. NRD is helpful to the early diagnosis of POAG.

Adult↗

PubMedDate not supplied

[Methods for screening the visual field for glaucoma].

The methods used for screening the visual field for glaucoma are not devoid of shortcomings, for their results can be false-positive as regards scotoma. Their advantages are not disputed. The methods we propose can rapidly detect not only disorders in the visual field, but assess them quantitatively in the area of special interest for the physician, specifically, in the Bjerrum area in screening for glaucoma. Although the results of screening perimetry are just tentative, it is desirable to assess the depth of optic sensitivity loss in decibells during such examinations. Static variants of screening perimetry, including that under conditions of loading tests (e.g. vacuum perimetry) acquire more and more significance in clinical and preclinical studies.

Adult↗

PubMed2003

Characteristics of visual field progression in patients with normal-tension glaucoma with optic disk hemorrhages.

PURPOSE: To study the characteristics of visual field progression in patients with normal-tension glaucoma (NTG) with optic disk hemorrhages. DESIGN: Observational study. METHODS: Fifty-eight eyes of 58 untreated patients with NTG who had at least five reliable visual fields of the Humphrey Field Analyzer (central 30-2) within the follow-up period of more than 24 months were enrolled. Of these, 27 eyes had optic disk hemorrhages in their clinical courses. Pointwise linear regression analysis was done using total deviation values of the fields at each of 74 test locations in each patient. Progression was defined as the points of negative slopes with P <.01. A whole visual field was concentrically divided into three clusters: the areas within 10 degrees, 10 to 20 degrees, and 20 to 30 degrees. Percentages of the progressed points of the three clusters and a whole field were compared between the groups with and without optic disk hemorrhages. RESULTS: No significant differences were found in patients' backgrounds, including initial mean deviation values, follow-up periods, and the number of visual field examinations between the 27 patients with optic disk hemorrhages and the 31 without. The group with optic disk hemorrhages showed significantly higher percentages of progressed points within the 10-degree area compared with the group without optic disk hemorrhages (mean +/- SD: 13.1 +/- 13.7%; 5.1 +/- 8.5%, respectively; P =.0086, Student t test), whereas no significant differences were found in the other two clusters or in a whole field. CONCLUSIONS: Patients with NTG with optic disk hemorrhages tend to show visual field progression in areas within 10 degrees.

Adult↗

PubMed1993

Fatigue effect within 10 degrees visual field in automated perimetry.

We studied the effect of fatigue within a 10 degree visual field measured with automated perimetry in normal volunteers (10 eyes), patients who have recovered from optic neuritis with multiple sclerosis (10 eyes), and patients with glaucoma (10 eyes). Using an Octopus 201, the visual field was tested with Program 61, which was centered (0.0), and 25 test locations were determined three times. Eight of the 25 points were selected for the evaluation. The mean sensitivity of the eight points was compared among the three measurements. Normal subjects and patients with optic neuritis showed no effect of fatigue within the 10 degrees visual field, but the patients with glaucoma indicated fatigue during the third measurement.

Adolescent↗

PubMed2005

Peripheral refraction along the horizontal and vertical visual fields in myopia.

Peripheral refractions were measured to 35 degrees eccentricity using a free-space autorefractor in young adult emmetropic and myopic subjects. Refractions were measured along horizontal and vertical visual fields for 116 subjects and a 43 subject subset, respectively. Along the horizontal visual field, peripheral myopic shifts in spherical equivalent M of emmetropes changed to relative hypermetropic shifts in the myopes, there were temporal-nasal asymmetries of 90 degrees to 180 degrees astigmatism J(180) which decreased as myopia increased, and 45 degrees to 135 degrees astigmatism J(45) was linearly related to field angle. Along the vertical visual field, both peripheral myopic shifts in peripheral M and J(180) asymmetry were unaffected by magnitude of myopia, and J(45) changed at three times the rate as for the horizontal visual field. Myopia has more effect on peripheral refraction of adult eyes along the horizontal than along the vertical visual field. The peripheral variations in refraction match well what is known about the shapes of emmetropic and myopic eyes.

Adolescent↗

PubMed1982

Visual evoked responses to reversal stimulation in the upper and lower half of the central part of the visual field in man.

Differences in visual evoked responses (VER) to three types of stimuli were studied in 70 volunteers, using checkerboard pattern reversal stimulation--a circular target in the central part of the visual field (VF) and stimuli composed of either the upper or the lower half of the circle. The responses to semicircular stimulation displayed great variability (latency shifts, reverse polarity, absence of a response), particularly to the upper half of the circle, where the amplitude of the responses was significantly smaller and their latency longer than in lower semicircle and whole circle stimulation.

Adult↗

PubMed1991

[Logistic regression analysis of risk factors of glaucomatous visual field defects].

30 patients (42 eyes) of early primary glaucoma with normal visual field were followed up for 2.5 years, during which time visual field defects developed in 24 eyes. Multivariate logistic regression analysis of the initial values of suspected risk factors demonstrated that a positive family history, the vertical C/D ratio, and the diurnal peak IOP were significant in predicting impending visual field defects.

Follow-Up Studies↗

PubMed1989

Test-retest variability in glaucomatous visual fields.

We measured test-retest variations in computerized visual fields from glaucomatous eyes. Fifty-one patients were tested four times within a four-week period; the severity of disease varied from incipient to advanced. We determined the dependence of threshold variability on defect depth and test point location. In areas of the visual field initially found to have moderate loss of sensitivity, variation in follow-up measurements ranged from normal sensitivity to absolute defect, with little dependence on distance from fixation. Conversely, large changes were considerably more unusual in locations initially showing normal or near-normal sensitivities, and variability was lowest in the most central portion of the field. Our findings suggest that differentiation between true progression and random variation will be facilitated if these factors are taken into account, as well as if comparisons are based on more than two tests. The complex nature of interest variation in glaucoma makes it natural to approach this problem with the help of computer-assisted analyses.

Adult↗

PubMed1985

Neuroretinal rim areas and visual field indices in glaucoma.

Magnification-corrected measurements of neuroretinal rim area of the optic disk were correlated to visual field indices calculated from 49 thresholds of Octopus program JO. The indices express overall reduction and localized disturbances of retinal sensitivity. The study was composed of 123 subjects, including 23 normal subjects, 49 patients suspected of having glaucoma, and 51 patients with glaucoma. The neuroretinal rim area was highly significantly correlated with both visual field indices; the index for overall loss of retinal sensitivity had a somewhat higher correlation coefficient than the index expressing localized visual field changes. Adequate fit of visual field data on rim area was achieved by quadratic regression.

Adult↗

PubMed1996

[Chronic open angle glaucoma: correlation of pattern electroretinography and visual field indices].

The pattern electroretinogram has already proven to be useful in detecting early stages of chronic open-angle glaucoma. We were interested in the degree of correlation between pattern ERG amplitudes and definite visual field defects. Fifteen glaucoma patients with a wide range of visual field defects were examined with pattern electroretinogram (stimulus with reversal rate of 8/s, checksizes of 0.9 degree and 6.9 degrees, covering a visual field of up to 9 degrees eccentricity). The patients' visual fields obtained with the Octopus 1-2-3 perimeter were analyzed with the perimetric analysis system PERIDATA using the indices of conformity for localized defects and the regional indices created from the mean deviation in certain parts of the 30 degrees field. In our results we were only able to find a significant correlation within the 5% level between the pattern ERG amplitudes and the sector index (large checksize, correlation coefficient r = -0.58, p = 0.03) and with the mean deviation in the region between 10 degrees and 20 degrees (small checksize, r = -0.538, p = 0.044). In summary, a marginal correlation between electrophysiological data and perimetric parameters was demonstrated. We try to explain the remarkable correlation between the amplitudes (small pattern) that were recorded from the central 9 degrees with the mean defects from the visual field peripheral of 10 degrees with the frequent combination of diffuse and localized field defects in glaucoma. Examination with the pattern ERG alone does not seem to be appropriate for grading the focal glaucomatous damage.

Adult↗

PubMed2007

Trained artificial neural network for glaucoma diagnosis using visual field data: a comparison with conventional algorithms.

PURPOSE: To evaluate and confirm the performance of an artificial neural network (ANN) trained to recognize glaucomatous visual field defects, and compare its diagnostic accuracy with that of other algorithms proposed for the detection of visual field loss. METHODS: SITA Standard 30-2 visual fields, from 100 glaucoma patients and 116 healthy participants, formed the data set. Our ANN was a previously described fully trained network using scored pattern deviation probability maps as input data. Its diagnostic accuracy was compared to that of the Glaucoma Hemifield Test, the Pattern Standard Deviation index at the P<5% and <1%, and also to a technique based on the recognizing clusters of significantly depressed test points. RESULTS: The included tests had early to moderate visual field loss (median MD=-6.16 dB). ANN achieved a sensitivity of 93% at a specificity level of 94% with an area under the receiver operating characteristic curve of 0.984. Glaucoma Hemifield Test attained a sensitivity of 92% at 91% specificity. Pattern Standard Deviation, with a cut off level at P<5% had a sensitivity of 89% with a specificity of 93%, whereas at P<1% the sensitivity and specificity was 72% and 97%, respectively. The cluster algorithm yielded a sensitivity of 95% and a specificity of 82%. CONCLUSIONS: The high diagnostic performance of our ANN based on refined input visual field data was confirmed in this independent sample. Its diagnostic accuracy was slightly to considerably better than that of the compared algorithms. The results indicate the large potential for ANN as an important clinical glaucoma diagnostic tool.

Adult↗

PubMed2000

Visual field assessment in glaucoma: comparative evaluation of manual kinetic Goldmann perimetry and automated static perimetry.

PURPOSE: To compare the detection and assessment of progression of visual field defects in primary open-angle glaucoma with manual suprathreshold perimetry on Goldmann perimeter and automated static threshold perimetry on Humphery visual field (HVF) analyzer. METHODS: 105 eyes of 54 patients of primary open-angle glaucoma were followed up with 3-monthly perimetry on Goldmann perimeter and HVF analyzer, for a period of 9 months. RESULTS: HVF analyzer picked up visual field defects in 48 (46%) eyes whereas Goldmann perimeter picked up visual field defects in 26 (25%) eyes. HVF analyzer demonstrated progression in 14 eyes whereas Goldmann perimeter detected progression in 7 eyes during follow up of 9 months. CONCLUSIONS: HVF analyzer is superior to Goldmann perimeter to document and to demonstrate progression of visual field defects in primary open-angle glaucoma.

Adolescent↗

PubMed2003

[Vigabatrin-associated bilateral simple optic nerve atrophy with visual field constriction. A case report and a survey of the literature].

CASE REPORT: A 70-year-old male with optic disc pallor and visual field constriction up to 35 degrees bilaterally was previously treated with vigabatrin. The cumulative dosage was 3.7 kg. The b-wave was reduced in photopic and scotopic electroretinography and the patient had delayed visual evoked potentials. The retinal nerve fiber thickness was pathologically reduced in the Heidelberg retinal tomography (HRT) and the retinal nerve fiber layer analyzer (GDx). CONCLUSION: Vigabatrin is an antiepileptic drug and may increase the intraretinal GABA level due to an inhibition of the enzyme GABA-transaminase and may induce an ascending simple optic nerve atrophy. Vigabatrin-associated visual field defects may be irreversible. A visual field control is recommended before starting the treatment with vigabatrin and at regular 6-month intervals thereafter. In cases of visual field constriction, the therapy should be stopped. If the cumulative dosage is more than 3 kg of vigabatrin, the visual field controls should be performed more frequently because of the dosage-toxicity relationship.

Aged↗

PubMed1985

Spatial and temporal parameters of motion detection in the peripheral visual field.

We present evidence that motion detectors in the peripheral visual field react to spatiotemporal structure in moving spatial white-noise patterns in a qualitatively similar fashion to those located near the center of gaze. Reichardt-type correlator mechanisms provide a simple theoretical framework in which all observed phenomena can be discussed. Two basic parameters of the correlator model are the time lag and the span. We have devised paradigms in which these parameters may be measured as a function of velocity and position in the visual field. Our results indicate that these parameters are primarily a function of the magnitude of the velocity (the span increasing and the lag decreasing as the velocity is increased) rather than of the retinal eccentricity. In another experiment, we determined the spatial resolution for apparent segregation of the visual image that is due to differential motion of detail in stationary rectangular gratings in which the pixels moved one way in the even bars and the other way in the odd bars. The limit of resolution occurs when the pixels traverse a bar of the grating in a given time, irrespective of the velocity or the retinal eccentricity. For higher velocities, the resolution is uniform over the entire visual field. For slower motion, the region of uniform (and relatively high) resolution shrinks to a region around the center of gaze. Resolution for segregation due to differential movement is at least 10 times worse than typical contrast-grating acuity.

Female↗

PubMed2002

Progression of visual field loss in untreated glaucoma patients and suspects in St Lucia, West Indies.

PURPOSE: A 1986-1987 survey found an 8.8% prevalence of open-angle glaucoma in the black population of St Lucia, West Indies. This follow-up study assessed progression of visual field loss in untreated glaucoma patients and persons with suspected glaucoma 10 years later. METHODS: Subjects were 205 patients with or suspected of having glaucoma. The 1987 data included age, sex, visual acuity, and visual fields measured by automated threshold perimetry (Humphrey C-30-2 test). The 1997 data included intraocular pressure, visual acuity, and visual fields measured by the same test. Exclusion criteria included field unreliability, field improvement due to vision improvement, nonglaucomatous vision deterioration, glaucoma treatment since 1988, and scoring of a field as end-stage in 1987. Visual fields were scored by algorithms for the Advanced Glaucoma Intervention Study (AGIS) and Collaborative Initial Glaucoma Treatment Study (CIGTS). RESULTS: By AGIS criteria, 55% of 146 right eyes and 52% of 141 left eyes progressed. In linear regressions, progression severity was unassociated with male or female sex, intraocular pressure, or baseline visual field score, but was positively associated with age (P < .001, right; P = .002, left). By CIGTS criteria, more eyes progressed. The cumulative probability of reaching end-stage disease in 10 years in at least on eye was about 16% by AGIS criteria and was 35% by CIGTS criteria. CONCLUSIONS: These data provide a unique opportunity to study progression of untreated glaucoma. A considerably larger percentage of eyes showed progression of visual field loss, and the rate of progression was greater than in studies of visual field loss in treated eyes.

Adult↗

PubMed2000

Visual field defects in patients taking vigabatrin.

PURPOSE: To investigate visual field loss in patients on long-term treatment with the antiepileptic drug vigabatrin, recently reported to cause visual disturbances. METHODS: Eighteen patients taking vigabatrin for 0.5-9.5 years were examined with automated perimetry up to 60 degrees from fixation using the Humphrey Field Analyser. Five patients with epilepsy receiving other medications served as controls. Patients found to have a visual field defect underwent ophthalmologic examination. RESULTS: Among the 18 patients in the vigabatrin group, visual field defects categorised as mild were revealed in 6 right eyes (33%) and 8 left eyes (44.4%), while defects categorised as severe were found in 9 right eyes (50%) and 8 left eyes (44.4%). The majority of the defects (66.7% in the right eye) were peripheral constriction with nasal predominance. The location of the defects was confirmed in 8 patients also tested with Kowa AP340 perimetry. CONCLUSION: According to our results, visual field defects among the patients on vigabatrin therapy may occur more frequently than previously recognised.

Adult↗

PubMed1988

On age-related norms of the visual field.

We prospectively studied the influence of age on visual fields obtained from 108 normal subjects (147 eyes) by using the Humphrey Field Analyzer (Program 30-2). Differential light sensitivity remained constant irrespective of age until the age of 35 to 44 years in the vast majority of test locations and then decreased linearly with age. The rate of linear decline differed at different test locations and failed to correlate with the eccentricity from the fixation, although its variance increased with the eccentricity. The mean sensitivity and the volume of the visual field were also constant until the age of 37.4 and 37.6 years, respectively.

Adolescent↗