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At least 37 records · Page 2Linked to original sources
PubMed1999

Effects of low alcohol consumption on visual evoked potential, visual field and visual contrast sensitivity.

PURPOSE: We studied changes in the vision of 16 people after consumption of a small quantity of alcohol, at a blood alcohol level (BAL) of 0.57 g/kg. METHODS: We studied visual contrast sensitivity (VCS) using Vistech VCTS 6500, visual evoked potential (VEP) by checked pattern stimulations and the peripheral visual field (PVF) with a perimetric automatic Humphrey. We first carried out the tests on sober people and then on individuals with a BAL of 0.57 g/kg. RESULTS: Alcohol consumption caused no significant difference in performance for these 3 tests. However, at a BAL of 0.57 g/kg there was a decrease in cerebral function, as shown by an increase in the number of mistakes made in the Wisconsin Card Sorting Test. CONCLUSION: These results suggest that for a low blood alcohol level, visual performance is less affected by the visual changes than by alteration in brain functions.

Adult↗
PubMed2006

Discordance between subjective perimetric visual fields and objective multifocal visual evoked potential-determined visual fields in patients with hemianopsia.

PURPOSE: To investigate the concordance between subjectively and objectively acquired visual fields in patients with subjectively determined hemianopsia. DESIGN: Retrospective observational study. METHODS: Ten patients, six men and four women, ranging in age from 28 to 68 years, were studied. Goldmann or Humphrey perimeters were used to obtain the subjectively determined visual fields for up to 25 degrees of eccentricity, and the VERIS Scientific System (Electro-Diagnostic Imaging, San Francisco, California, USA) was used to record multifocal visual evoked potential [VEPs] (mfVEPs) to obtain the objective visual fields. Each of the 60 black-and-white segments of the checkerboard stimulus was alternated according to a binary m sequence. The first slices of the second-order kernels were extracted and analyzed. RESULTS: In five cases, the visual field loci where the mfVEPs were within normal limits corresponded to the scotomatous areas obtained by conventional perimetry. In these discordant cases, the lesions (e.g., arteriovenous malformation) were located in the occipital lobe. Two of these cases had a complete recovery of the subjective visual field. The lesions of the concordant cases were located outside the occipital lobe (e.g., pituitary adenoma). In these cases, no visual field improvement was seen. The temporal crescent syndrome was ruled out in patients with posterior lesions by computed tomography (CT) or magnetic resonance imaging (MRI) findings. CONCLUSIONS: In some patients with occipital lesions, the subjective and objective visual field results are discordant, and some of them will show a recovery of the visual field deficits.

Adult↗
PubMed2000

Reading with eccentric fixation is faster in inferior visual field than in left visual field.

PURPOSE: People with central field loss tend to fixate so that information falls in the inferior or left visual field. Studies of reading from a page of text suggest that using inferior field is advantageous relative to using left visual field. In this study, we investigated whether reading without eye movements in normal peripheral vision is better when text is presented in inferior or left visual field. METHODS: Reading rates were determined for retinally stabilized rapid serial visual presentation sentences of seven letter sizes, presented at 5 degrees in inferior and left visual field of six normal observers. RESULTS: When print size is appropriately magnified for peripheral viewing, reading speed in inferior field is faster than in left visual field. There is no significant difference between inferior and left visual field in the print size required to reach maximum reading speed. CONCLUSIONS: For reading tasks not involving eye movements, there is an advantage in eccentrically fixating such that text falls in inferior rather than left visual field.

Adult↗
PubMed1981

Xenon arc and argon laser photocoagulation in the treatment of diabetic disc neovascularization. Part 1. Effect on disc vessels, visual fields, and visual acuity.

Xenon arc and argon laser photocoagulation are equally effective in producing regression of disc neovascularization and maintaining visual acuity. Xenon has more destructive effects on the visual field and electroretinogram, but is more comfortable because retrobulbar anaesthesia is used and more convenient to the patient because fewer treatment sessions are needed.

Adult↗
PubMed1994

Topographic mapping of the pattern onset evoked magnetic response to stimulation of different portions of the visual field.

Visual evoked magnetic responses to pattern onset/offset stimuli were recorded in 5 normal subjects. The outgoing and ingoing magnetic currents were seen maximally over the contralateral visual cortex to the half field stimulated in the majority of subjects. The distribution of magnetic currents with half field stimulation would be consistent with a dipole on the midline with the positive end pointing laterally. Quadrantic stimuli produced dipoles which would be consistent with a vector sum of dipoles situated, in the case of upper quarter field stimulation, in the lingual gyri on the floor of the calcarine fissure. Lower quadrantic stimulation produced a vector consistent with dipoles on the cuneal gyrus and on the ceiling of the calcarine fissure producing a resultant vector. The use of paired octant stimuli to improve localisation was demonstrated on both right left and upper and lower half fields.

Adult↗
PubMed1983

Comparative studies of color fields, visual acuity fields, and movement perception limits among varsity athletes and non-varsity groups.

This paper examined effects of sports practice on patterns of color fields, limits of peripheral movement perception, and visual acuity field by comparing varsity ball players and non-varsity control groups. The first study measured extent of color fields and limits of horizontal and vertical meridians for peripheral movement perception of 139 college students. The second study tested visual acuity fields of female and male basketball players and female and male controls. The first study indicated that athletes had wider limits for horizontal movement perception, while the non-athletes had better vertical movement perception limits. Basketball players demonstrated color fields and limits for peripheral movement perception superior to those of soccer players. In the second study, athletes did not have any wider visual acuity fields than non-athletes, but their movement-perception limits were significantly wider than those of non-athletes.

Color Perception↗
PubMed1980

Role of structured visual field and visual reafference in accuracy of pointing movements.

In a visuo-motor pointing task, the accuracy of response was measured in situations which differ in the visual information available and the speed of execution of movement. Results confirm the role of visual cues received from self-produced movement in the control of the trajectory of a limb. Furthermore, it can be shown that a structured visual background is important in the treatment of sensory data concerned with the movement and in target localization. This effect is absent in rapidly executed pointing response.

Cues↗
PubMed1992

Spatial analyses of glaucomatous visual fields; a comparison with traditional visual field indices.

Interpretation of numeric automated threshold visual field results is often difficult. A large amount of data is obtained for every single field tested. Various approaches to summarize this data have been suggested, most commonly the mean and standard deviation of departures from age-corrected normal threshold values. These visual field indices differ substantially from subjective field interpretation where spatial relationships are important. We have previously devised two methods for automated field interpretation which take spatial information into account--regional up-down comparisons and arcuate cluster analysis. We now studied the merits of using these new spatial methods and compared them to traditional visual field indices for discrimination between normal and glaucomatous field results. Central static 30 degree field results in 101 eyes of 101 normal subjects and 101 eyes of 101 patients with glaucoma were discriminated using logistic regression analysis. The best field classification was obtained with a spatial visual field model combining up-down differences and arcuate clusters. The advantages of the spatial model were confirmed in an independent material of 163 eyes of 163 normal subjects and 76 eyes of 76 patients with glaucoma where eyes with large field defects had been removed. In this material the spatial model gave 87% sensitivity and 83% specificity while the best non-spatial model gave 82% sensitivity and 80% specificity. Visual field interpretation in glaucoma may be significantly enhanced if detection is focused on circumscribed field loss rather than on averages of differential light sensitivities and similar indices which do not take spatial relationships into consideration.

Adult↗
PubMed2005

[Conventional techniques of visual field examination Part 2: confrontation visual field testing -- kinetic perimetry].

Evaluation of visual field findings is an essential ophthalmological task. Applying psychophysical principles enables noninvasive (topo-)diagnosis in cases of unexplained visual loss or suspected lesions of the visual pathway. Furthermore, any kind of expert opinion or ability test critically depends on adequate visual field findings. Repeated examinations allow functional follow-up of a disease and assessment of therapeutic efficiency. This paper explicitly focuses on conventional strategies since these are widespread, easily accessible, standardized, and well established in everyday practice over years. Standardized white-on-white perimetry with moving targets (kinetic perimetry) is the major topic of this paper (part 2) in addition to "rough"/preliminary confrontation visual field testing. This review series is aimed at imparting basic concepts in perimetry and psychophysics to ophthalmologists and also addresses interested physicians from other disciplines.

Eye Movements↗
PubMed2004

Increased rate of visual field loss associated with larger initial visual field threshold values on follow-up of open-angle glaucoma.

PURPOSE: To determine the changes in the visual field over time and the factors that contribute to these changes on follow-up of open-angle glaucoma patients. PATIENTS AND METHODS: From a retrospective review of patients' charts and visual fields, 30 eyes from 30 patients with open-angle glaucoma with a minimum of 3 years of follow-up were chosen. Visual fields were obtained with the Octopus perimeter about every 4 months. Regression analysis was used to obtain the slope for all the threshold values for each eye for the total field and nine different regions over time. Optic disc area was measured from single fundus photographs obtained at the beginning of the period of observation. RESULTS: The open-angle glaucomas were observed for a mean of 6.7 +/- 2.3 years. The number of visual fields per eye was 20.7 +/- 8.0. The mean threshold value of the total field for the first three visual fields was 18.0 +/- 5.2 dB. The visual fields of the 30 eyes with a mean intraocular pressure of 18 +/- 2 mm Hg during follow-up showed a significant decrease in their visual field slope of -0.384 dB/y for the total visual field. On multivariate analysis, the slope or rate of visual field loss was significantly correlated with the average of the first three initial visual field thresholds for the total visual field, temporal, and central regions so that the greater the threshold value the more rapid the rate of the visual field loss. For the total visual field and for the nasal, superior nasal, and temporal regions with lower initial threshold values, the rate of visual field loss was curvilinear with the rate of visual field loss increasing at greater initial mean threshold values. The other regions of the visual field showed a linear increasing rate of visual field loss with larger initial threshold values. Other factors significantly associated with progression of visual field loss were refractive error, race, the slope of the pulse rate, and the mean percent false positives and false negatives for initial to final observations. The mean and the slope of intraocular pressure from initial to final observation were not significant variables. CONCLUSION: In open-angle glaucomas observed for 6.7 +/- 2.3 years, there was a more rapid rate of visual field loss associated with larger initial threshold values and a less rapid rate of visual field loss associated with smaller initial threshold values indicating that the progression of visual field loss is greater in an earlier stage of disease.

Differential Threshold↗
PubMed2006

Contrasting blue-on-yellow with white-on-white visual fields: Roles of visual adaptation for healthy peri- or postmenopausal women younger than 70 years of age.

PURPOSE: To test the hypothesis that differences between short-wavelength automated perimetry (SWAP) and white-on-white visual field sensitivities are related to between-individual variation in the visual adaptation properties of SWS cone pathways. METHODS: Twenty-six healthy amenorrheic (peri- or postmenopausal) women not using hormonal medication were tested. Subjects ranged in age from 48 to 68 years. They were tested by using foveal increment-threshold techniques and also with two types of 24-2 visual field tests: a full-threshold SWAP blue-on-yellow (B/Y) test and a white-on-white (W/W) test obtained using a Swedish Interactive Threshold Algorithm (SITA Standard). The age-corrected sensitivity differences between the two types of visual fields were compared against foveal measures of visual sensitivity and adaptation, which were obtained psychophysically using dim and bright yellow backgrounds. All measurements for each subject were made at a single testing session. The comparisons were made for the entire visual field and for separate portions of the visual field. The analyses also included pupil size data obtained during visual field testing. RESULTS: The B/Y minus W/W (B/Y - W/W) mean deviation difference was described (R = 0.80) by a multilinear model with three significant factors: (1) an adaptation factor and (2) a baseline sensitivity factor, each derived from the foveal psychophysical data for short-wavelength test stimuli, and (3) a pupil size factor, as recorded for SWAP. The total deviation differences in the periphery of the visual field (approximately 22 degrees from fixation) were described (R = 0.87) by a model with four significant factors, the fourth being an "eccentricity factor" describing the rate of change of the B/Y - W/W total deviation difference measured as a function of increasing retinal eccentricity approximately 9 degrees -17 degrees from fixation. More than 40% of the variance in the B/Y - W/W mean deviation differences was accounted for either directly or indirectly (via effects of pupil size) by variations in adaptation to the yellow background used for SWAP. CONCLUSIONS: Much of the extra variability in SWAP sensitivities for a select group of healthy women can be accounted for by differences in the degree of desensitization induced by the yellow background used for SWAP. For clinical practice, pupil status (dilated or undilated) should be altered only with caution from one SWAP testing session to another.

Adaptation, Ocular↗
PubMed1994

The effect of panretinal laser photocoagulation on visual acuity, visual fields and on subjective visual impairment in preproliferative and early proliferative diabetic retinopathy.

The effect of panretinal laser scatter treatment on visual fields, visual acuity and subjective complaints was assessed in 11 patients with severe nonproliferative or early proliferative diabetic retinopathy. Patients were prospectively examined before and after panretinal treatment using automated static threshold perimetry with program 30-2 on the Humphrey perimeter, and they were interviewed. Visual field sensitivity was often depressed even before treatment with mean MD -4.3 (-1, -11.6) dB, but was significantly lower (p < 0.01, ANOVA) 2 weeks after treatment with mean MD -8.6 dB. Visual fields remained stable 4 months later. Treatment increased the number of eyes with visual fields as defined by abnormal MD values at the p < 0.05 level from 8 to 16 among the 17 treated. In spite of considerable impairment of visual fields after treatment, subjective problems were small and the visual field impairment seemed to have little influence on everyday life.

Adult↗
PubMedDate not supplied

Combined influences of gravitoinertial force level and visual field pitch on visually perceived eye level.

Psychophysical measurements of the level at which observers set a small visual target so as to appear at eye level (VPEL) were made on 13 subjects in 1.0 g and 1.5 g environments in the Graybiel Laboratory rotating room while they viewed a pitched visual field or while in total darkness. The gravitoinertial force was parallel to the z-axis of the head and body during the measurements. The visual field consisted of two 58 degrees high, luminous, pitched-from-vertical, bilaterally symmetric, parallel lines, viewed in otherwise total darkness. The lines were horizontally separated by 53 degrees and presented at each of 7 angles of pitch ranging from 30 degrees with the top of the visual field turned away from the subject (top backward) to 30 degrees with the top turned toward the subject (top forward). At 1.5 g, VPEL changed linearly with the pitch of the 2-line stimulus and was depressed with top backward pitch and elevated with top forward pitch as had been reported previously at 1.0 g (1,2); however, the slopes of the VPEL-vs-pitch functions at 1.0 g and 1.5 g were indistinguishable. As reported previously also (3,4), the VPEL in darkness was considerably lower at 1.5 g than at 1.0 g; however, although the y-intercept of the VPEL-vs-pitch function in the presence of the 2-line visual field (visual field erect) was also lower at 1.5 g than at 1.0 g as it was in darkness, the G-related difference was significantly attenuated by the presence of the visual field. The quantitative characteristics of the results are consistent with a model in which VPEL is treated as a consequence of an algebraic weighted average or a vector sum of visual and nonvisual influences although the two combining rules lead to fits that are equally good.

Adult↗